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{{Acinic cell carcinoma}}
{{Acinic cell carcinoma}}
{{CMG}}{{Swathi}}
{{CMG}}; {{AE}} {{RG}}
 
==Overview==  
==Overview==  
 
[[Acinic cell carcinoma]] (ACC) is a low-grade [[malignant]] [[Salivary Gland Tumor|salivary]] neoplasm that constitutes approximately 17% of primary [[salivary gland]] [[malignancies]]. In the [[head]] and [[neck]] region, the [[parotid gland]] is the predominant site of origin. This tumor is usually a low-grade, highly differentiated [[carcinoma]]. Women are usually more frequently diagnosed than men.  There are many risk factors, including [[cigarette smoking]], [[Genetics|genetic]] predisposition, [[radioactive]] substances, [[viral infections]], rubber manufacturing, plumbing equipment and some types of woodworking, as well as [[asbestos]] mining and exposure to [[nickel]] compounds. Patients typically present with a slowly enlarging [[mass]] in the [[parotid]] region, [[nausea]], [[vomiting]] and [[digestion]] problems. Treatments include complete [[surgical resection]], [[chemotherapy]], and [[radiation therapy]]. [[Acinic cell carcinoma]] was considered as a [[benign neoplasm]] until 1953. All [[Acinic cell carcinoma|acinic cell carcinomas]] were classified as [[neoplasms]] in the [[World Health Organization|WHO]]'s international classification of disease for [[oncology]] by 1972. In a second edition, all [[Acinic cell carcinoma|acinic cell carcinomas]] considered as [[adenocarcinoma]] by 1990. Batsakis et al, described [[acinic cell carcinoma]] as a derivative from [[Progenitor cell|progenitor reserve cells]] of terminal [[tubules]] and [[Intercalated duct|intercalated ducts]] of salivary tissue for the first time. [[Acinic cell carcinoma|Acinic cell carcinoma,]] a [[salivary gland]] [[tumor]], mainly develop in [[parotid gland]] (81000 out of 100000), less common, it occurs in the [[submandibular gland]] and [[Salivary gland tumor|minor salivary glands]] of [[palate]]. It belongs to the family of [[adenocarcinoma]] which share similarities with: [[Adenoid cystic cancer|Adenoid cystic]], [[Mucoepidermoid carcinoma|Muco-epidermoid]], low-grade [[adenocarcinoma]] and some [[Breast cancer|breast cancers]]. The development of [[Acinic cell carcinoma|acinic cell carcinomas]] is the result of multiple [[genetic mutations]] that suggest association of tumor suppression genes such as: [[Chromosome 5|Chromosome 5q]], [[Chromosome 6|chromosome 6p]], [[Chromosome 17|chromosome 17p]], deletions of [[Chromosome 6|chromosome 6q]], loss of [[Y chromosome|chromosome Y]], [[Down syndrome|Trisomy 21]]. Molecular studies suggest that [[retinoblastoma]] pathway also can be involved with [[Acinic cell carcinoma|acinic cell carcinomas]]. [[Acinic cell carcinoma]] is a [[Head and neck cancer|head and neck tumor]] happening in the [[salivary glands]]. If a patient was observed with related signs, the [[tumor]] must be classified as a [[benign]] or [[invasive]] by the [[capsule]] being intact. [[Differential diagnosis]] of a [[malignant]] tumor in [[salivary gland]] is made after the [[incision]] and by [[histology]] features which will provide a good [[chemotherapy]] regimen for so called patients. In western countries, [[salivary gland]] [[carcinomas]] account for 4000 out of 100000 of all [[Head and neck cancer|head and neck carcinomas]], and approximately 80% of those occurring in [[parotid gland]]. one out of six [[parotid gland]] cancer is [[Acinic cell carcinoma|acinic cell carcinomas]]. Distribution of [[acinic cell carcinoma]] between age groups seems to be quiet even, with a median age of 52 years, but it occurs mostly at a younger age. Children are rarely affected with [[salivary gland]] [[carcinoma]], but if they are, it is most likely to be [[acinic cell carcinoma]]. [[Acinic cell carcinoma]] is predominantly seen in in whites (85000 out of 100000 cases) and less in African nations(8000 out of 100000 cases) here is a higher [[incidence]] among female with the ratio ranging from 1.43:1 to 1.57:1. There is very little approved information about [[acinic cell carcinoma]] risk factors but familial predisposition and previous [[radiation exposure]] may play an important role. [[Screening]] is not recommended for [[acinic cell carcinoma]]. Once diagnosis confirmed, [[ultrasonography]], nuclear scans, [[Computed tomography|CT scan]] and [[Magnetic resonance imaging|MRI]] can usually conduct for assessing the size of the [[tumor]], location, and the nature of the tumor. [[Parotid gland]], is the most common site for [[acinic cell carcinoma]] affection. Typically, [[acinic cell carcinoma]] is a slow growing [[mass]], lacking other [[Symptom|symptoms]]. Pain or fixation to surroundings is a sign of poor [[prognosis]]. Nodal [[metastasis]] of [[acinic cell carcinoma]] is extremely rare. Another rare [[Complications|complication]] is [[Facial nerve|cranial nerve VII]] dysfunction. A small minority of of [[acinic cell carcinoma]] occurs in [[Sinonasal undifferentiated carcinoma|sinonasal]] area or [[larynx]], there is a big controversy about bilateral [[acinic cell carcinoma]], it is still unknown if it invades bilateral glands or just a unilateral tumor. Common sites for non-salivary [[acinic cell carcinoma]] is [[lacrimal gland]], [[pancreas]], and [[breast]]. [[Acinic cell carcinoma]] in [[pancreas]] are so called as [[acinar cell carcinoma]]. The prognostic factors are [[age]], [[pain]], gender, [[race]], previous inadequate treatment, extent of disease and invasion of the [[skull]] base. [[Physical examination]] of [[neck]] may reveal a firm [[swelling]] and [[tenderness]]. Clinical stage, particularly tumor size, may be the critical factor to determine the outcome of [[salivary gland]] cancer and may be more important than histologic grade. [[TNM|TNM system]] is the system of choice for studying [[acinic cell carcinoma]]. [[Acinic cell carcinoma]] is usually anatomically accessible [[tumor]] and patient do not show far [[metastasis]] at the time of [[diagnosis]], the treatment of choice is surgery with [[resection]] of all free margins. Since [[Acinic cell carcinoma (patient information)|acinic cell carcinoma]] could be neglected, a high rate of recurrence after first resection have been reported. Low grade [[acinic cell carcinoma]] will be cured with surgery alone, but the site of origin indicates extension of [[resection]]. Superficial [[parotidectomy]] often effects complete removal of [[acinic cell carcinoma]], but conservative [[parotidectomy]] is indicated if the deep lobe is involved. Initial approach would be more aggressive if the [[tumor]] is locally advanced [[acinic cell carcinoma]], the [[facial nerve]] cannot be preserved, it must be [[Resection|resected]] and reconstructed with an [[autograft]] from [[Great auricular nerve|greater auricular]] or [[Sural nerve|sural]] [[nerve]]. Elective neck dissection is not recommended in [[acinic cell carcinoma]], because of low risk of regional [[lymph node]] [[metastasis]]. However studies have revealed additional neck dissection decrease the rate of recurrence.
Acinic cell carcinoma (ACC) is a low-grade malignant salivary neoplasm that constitutes approximately 17% of primary salivary gland malignancies. In the head and neck region, the parotid gland is the predominant site of origin. This tumor is usually a low-grade, highly differentiated carcinoma. Women are usually more frequently diagnosed than men.  There are many risk factors, including cigarette smoking, genetic predisposition, radioactive substances, viral infections, rubber manufacturing, plumbing equipment and some types of woodworking, as well as asbestos mining and exposure to nickel compounds. Patients typically present with a slowly enlarging mass in the parotid region, nausea, vomiting and digestion problems. Treatments include complete surgical resection, [[chemotherapy]], and radiation therapy.
<ref name="pmid20063555">{{cite journal| author=Al-Zaher N, Obeid A, Al-Salam S, Al-Kayyali BS| title=Acinic cell carcinoma of the salivary glands: a literature review. | journal=Hematol Oncol Stem Cell Ther | year= 2009 | volume= 2 | issue= 1 | pages= 259-64 | pmid=20063555 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=20063555  }} </ref>


==Historical Perspective==
==Historical Perspective==
[[Acinic cell carcinoma]] was discovered as a [[benign neoplasm]] until 1953.


*ACC was referred to as an entity for the first time more than 50 years ago by Godwin et al
All [[Acinic cell carcinoma|acinic cell carcinomas]] were classified as [[Neoplasm|neoplasms]] in the [[World Health Organization|WHO]]'s international classification of disease for [[oncology]] by 1972. In a second edition, all acinic cell neoplasms considered as [[adenocarcinoma]] by 1990. Batsakis et al, described [[acinic cell carcinoma]] as a derivative from [[Progenitor cell|progenitor reserve cells]] of terminal [[tubules]] and [[Intercalated duct|intercalated ducts]] of salivary [[Tissue (biology)|tissue]] for the first time.
*The “acinar” term is derived from Latin term “acinus”, which means a cluster of and looks like grapes branch
*The histological appearance is quite similar to secretory parenchymatous cells. <ref name="acinar" cell="" ca="">{{cite web |url=http://www.sciencedirect.com/science/article/pii/S1658387609500350#bb0005 |title=Acinic cell carcinoma of the salivary glands: A literature review - ScienceDirect |format= |work= |accessdate=}}</ref>
*Before discovering this disease, clinically Acinic Cell Carcinoma was unrecognized.
*At the time after recognizing the disease, it thought to be the nature of the tumor is benign.
*Afterward, it has been detected that the recurrence tendency of the tumor showed the possibility of the malignant nature of the tumor.
*Later WHO (World Health Organization) re-classified as a “malignant carcinoma” with low-grade behavior (2, 3).


==Pathophysiology==
==Pathophysiology==


Features of acinic cell carcinoma on fine needle aspiration include stippled chromatin and granular cytoplasm.
[[Acinic cell carcinoma]], a [[salivary gland]] [[tumor]], mainly develop in [[parotid gland]] (81000 out of 100000), less common. [[Acinic cell carcinoma]] occurs in the [[submandibular gland]] and [[Salivary gland tumor|minor salivary glands]] of [[palate]]. [[Acinic cell carcinoma]] belongs to the family of [[adenocarcinoma]] with similarities like: [[Adenoid cystic cancer|Adenoid cystic]], [[Mucoepidermoid carcinoma|Muco-epidermoid]], low-grade [[adenocarcinoma]], some [[Breast cancer|breast cancers]]. The development of [[acinic cell carcinoma]] is the result of multiple [[genetic mutations]] that suggest association of tumor suppression genes such as: [[Chromosome 5|chromosome 5q]], [[Chromosome 6|chromosome 6p]], [[Chromosome 17|chromosome 17p]], deletions of [[Chromosome 6|chromosome 6q]], loss of [[Y chromosome|chromosome Y]], [[Down syndrome|Trisomy 21]], molecular studies suggest that [[retinoblastoma]] pathway also can be involved with [[acinic cell carcinoma]].  
 
=== Microscopic Pathology ===
 
* Cytologic features of acinic cell carcinoma on fine needle aspiration:
* Chromatin stippled.
* Granular cytoplasm.
* Sheets of cells/acinar formation.


==Differential diagnosis==
==Differential diagnosis==


Acinic cell carcinoma should be differentiated from parotitis, parotid gland benign tumor and mucoepidermoid carcinoma.
[[Acinic cell carcinoma]] is a head and neck tumor happening in the [[salivary glands]]. If a patient was observed with related signs, the tumor must be classified as a [[benign]] or [[invasive]] by the [[capsule]] being intact. Differential diagnosis of a [[malignant]] tumor in the salivary gland is made after the incision and by [[histology]] features which will provide a good [[chemotherapy]] regimen for so-called patients.


==Epidemiology and demographics==
==Epidemiology and demographics==


Acinic cell carcinoma can appear at any age however, it is common in children.
In western countries, [[salivary gland]] [[carcinomas]] account for 4000 out of 100000 of all [[Head and neck cancer|head and neck]] carcinomas, and approximately 80% of those occurring in [[parotid gland]]. One out of six [[parotid gland]] cancer is [[acinic cell carcinoma]]. Distribution of [[acinic cell carcinoma]] between age groups seems to be quiet even, with a median age of 52 years, but it occurs mostly at a younger age. Children are rarely affected with [[salivary gland]] [[carcinoma]], but if they are it is most likely to be [[acinic cell carcinoma]]. [[Acinic cell carcinoma]] is predominantly seen in whites (85000 out of 100000 cases) and less in African nations(8000 out of 100000 cases)here is a higher [[incidence]] among female with the ratio ranging from 1.43:1 to 1.57:1.  
 
* Acinic cell carcinoma appears in all age groups, but presents at a younger median age (approx. 52 years) than most other salivary gland cancers.
* Occurrences in children are quite common.
 
<br />


==Risk factors==
==Risk factors==


Radiation exposure and positive family history are known risk factors for acinic cell carcinoma.
There is very little approved information about [[acinic cell carcinoma]] risk factors but familial predisposition and previous [[radiation]] exposure may play an important role.
 
 
Clinical data has suggested that the development of acinic cell carcinoma is related to several factors.
 
* '''Radiation exposure:''' Radiation treatment for the head and neck cancer increases the risk of developing salivary gland cancer. Workplace exposure to certain radioactive substances may also increase the risk of salivary gland cancer.
* '''Family history:''' Some epidemiological data suggest that members of some families seem to have a higher than usual risk of developing salivary gland cancers.


==Screening==
==Screening==


Screening is not recommended for acinic cell carcinoma.
There is insufficient evidence to recommend routine screening for acinic cell carcinoma. Once diagnosis confirmed, [[ultrasonography]], [[nuclear]] scans, [[CT scan]] and [[Magnetic resonance imaging|MRI]] can usually conduct for assessing the size of the [[tumor]], location, and the nature of the [[tumor]].


== Natural history, prognosis and complications==
== Natural history, prognosis and complications==


Acinic cell carcinoma is a slow growing tumor and it may affect the facial nerve or other adjacent tissues depending on its location. Prognosis is most favorable when the parotid gland is involved.
[[Parotid gland]], is the most common site for [[acinic cell carcinoma]] affection. typically, [[acinic cell carcinoma]] is a slow-growing mass, lacking other [[Symptom|symptoms]]. pain or fixation to surroundings is a sign of poor prognosis. nodal [[metastasis]] of [[acinic cell carcinoma]] is extremely rare. another rare complication is [[Facial nerve|cranial nerve VII]] dysfunction. a small minority of [[acinic cell carcinoma]] occurs in [[Sinonasal undifferentiated carcinoma|sinonasal]] area or [[larynx]]. there is a big controversy about bilateral acinic cell carcinoma, it is still unknown if it invades bilateral glands or just a unilateral tumor. common sites for non-salivary acinic cell carcinoma is [[lacrimal gland]], [[pancreas]], and [[breast]]. [[Acinic cell carcinoma]] in the pancreas are so-called [[acinar cell carcinoma]]. the prognostic factors are age, pain, gender, race, previous inadequate treatment, the extent of disease, invasion of the skull base.
Acinic cell carcinoma is a slow growing tumor and it may affect the facial nerve or other adjacent tissues depending on its location. Prognosis is most favorable when the parotid gland is involved.
Progression of acinic cell carcinoma is slow but it may involve adjacent tissues if not treated adequately.
Acinic cell carcinoma can spread to adjacent organs and eventually be lethal if not intervened on time.
The prognosis is more favorable when the tumor is in a major salivary gland; the parotid gland is most favorable, then the submandibular gland; the least favorable primary sites are the sublingual and minor salivary glands. Large bulky tumors or high-grade tumors carry a poorer prognosis and may best be treated by surgical resection combined with postoperative radiation therapy.<ref name="pmid8655366">{{cite journal| author=Parsons JT, Mendenhall WM, Stringer SP, Cassisi NJ, Million RR| title=Management of minor salivary gland carcinomas. | journal=Int J Radiat Oncol Biol Phys | year= 1996 | volume= 35 | issue= 3 | pages= 443-54 | pmid=8655366 | doi= | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=8655366  }} </ref> The prognosis depends on the following:<ref name="pmid10223248">{{cite journal| author=Vander Poorten VL, Balm AJ, Hilgers FJ, Tan IB, Loftus-Coll BM, Keus RB et al.| title=The development of a prognostic score for patients with parotid carcinoma. | journal=Cancer | year= 1999 | volume= 85 | issue= 9 | pages= 2057-67 | pmid=10223248 | doi= | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=10223248  }} </ref><ref name="pmid15287035">{{cite journal| author=Terhaard CH, Lubsen H, Van der Tweel I, Hilgers FJ, Eijkenboom WM, Marres HA et al.| title=Salivary gland carcinoma: independent prognostic factors for locoregional control, distant metastases, and overall survival: results of the Dutch head and neck oncology cooperative group. | journal=Head Neck | year= 2004 | volume= 26 | issue= 8 | pages= 681-92; discussion 692-3 | pmid=15287035 | doi=10.1002/hed.10400 | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=15287035  }} </ref>
 
==History and symptoms==
 
Acinic cell carcinoma commonly presents with a mass in the neck, difficulty in swallowing and persistent pain.
 
Early acinic cell carcinoma does not have any symptoms. As the tumor grows larger, people may notice one or more of the following symptoms:
 
* A mass or lump in face, neck, or mouth area.
* Persistent pain.
* A newly noticed difference between the size and/or shape of the left and right sides of face or neck region.
* Numbness in part of face.
* New weakness of the muscles on one side of face.
* Pain and difficulty in swallowing.
 
Other diseases may also present with similar symptoms.


==Physical Examination==
==Physical Examination==


Physical examination of neck may reveal a firm swelling and tenderness.
[[Physical examination]] of [[neck]] may reveal a firm swelling and [[tenderness]].
<gallery>
Image:8704.jpg|Mastocytoma.  <BR><SMALL><SMALL>With permission from <ref>{{cite web|url=http://www.atlasdermatologico.com.br/disease.jsf?diseaseId=5Dermatology Dermatology Atlas|title=mastocytoma}}</ref> </small></small>
</gallery>
 
==Staging==
 
Staging of acinic cell carcinoma depends on tumor size and location.
In general, tumors of the major salivary glands are staged according to size, extraparenchymal extension, lymph node involvement (in parotid tumors, whether or not the facial nerve is involved), and presence of metastases. Tumors arising in the minor salivary glands are staged according to the anatomic site of origin (e.g., oral cavity and sinuses).


Clinical stage, particularly tumor size, may be the critical factor to determine the outcome of salivary gland cancer and may be more important than histologic grade. Diagnostic imaging studies may be used in staging. With excellent spatial resolution and superior soft tissue contrast, magnetic resonance imaging (MRI) offers advantages over computed tomographic scanning in the detection and localization of head and neck tumors. Overall, MRI is the preferred modality for evaluation of suspected neoplasms of the salivary glands.
== Staging ==
Clinical stage, particularly [[tumor]] size, maybe the critical factor to determine the outcome of [[salivary gland]] [[cancer]] and maybe more important than a [[histologic]] grade. [[TNM|TNM system]] is the system of choice for studying [[acinic cell carcinoma]].  


==Treatment==  
==Treatment==  
Patients with acinic cell carcinoma have many treatment options. The selection depends on the stage of the tumor. The options are surgery, radiation therapy, chemotherapy, or a combination of these methods.  
[[Acinic cell carcinoma]] is usually anatomically accessible [[tumor]] and patient do not show far [[metastasis]] at the time of [[diagnosis]], the treatment of choice is [[surgery]] with [[resection]] of all free margins. Since [[Acinic cell carcinoma (patient information)|acinic cell carcinoma]] could be neglected, a high rate of recurrence after first [[resection]] have been reported. low grade [[acinic cell carcinoma]] will be cured with surgery alone, but the site of origin indicates extension of resection. Superficial [[parotidectomy]] often effects complete removal of [[acinic cell carcinoma]], but conservative [[parotidectomy]] is indicated if the deep lobe is involved. Initial approach would be more aggressive if the tumor is locally advanced [[acinic cell carcinoma]], the [[facial nerve]] cannot be preserved, it must be resected and reconstructed with an [[autograft]] from [[Great auricular nerve|greater auricular]] or [[Sural nerve|sural]] nerve. Elective [[neck]] dissection is not recommended in [[acinic cell carcinoma]], because of low risk of regional [[lymph node]] [[metastasis]]. However studies have revealed additional [[neck]] dissection decrease the rate of recurrence.  
*'''Surgery:''' Surgery is usually the main form of treatment for resectable salivary gland cancers.
*'''Radiation therapy:''' High-energy x-rays and other types of radiations are used to kill cancer cells from keep growing.
*'''Chemotherapy:''' The treatment is to use drugs to stop the growth of cancer cells either by killing the cells or by stopping them from dividing.
 
===Surgery===
Surgery is usually the main form of treatment for resectable salivary gland cancers.Large bulky tumors or high-grade tumors carry a poorer prognosis and may best be treated by surgical resection combined with postoperative radiation therapy.<ref name="pmid8655366">{{cite journal| author=Parsons JT, Mendenhall WM, Stringer SP, Cassisi NJ, Million RR| title=Management of minor salivary gland carcinomas. | journal=Int J Radiat Oncol Biol Phys | year= 1996 | volume= 35 | issue= 3 | pages= 443-54 | pmid=8655366 | doi= | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=8655366  }} </ref>
==Follow-up after treatment==
==Follow-up after treatment==
Complications of surgical treatment for parotid neoplasms include facial nerve dysfunction and frey syndrome, also known as gustatory flushing or auriculotemporal syndrome.<ref name="pmid12593546">{{cite journal| author=Gooden E, Witterick IJ, Hacker D, Rosen IB, Freeman JL| title=Parotid gland tumours in 255 consecutive patients: Mount Sinai Hospital's quality assurance review. | journal=J Otolaryngol | year= 2002 | volume= 31 | issue= 6 | pages= 351-4 | pmid=12593546 | doi= | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=12593546  }} </ref>Frey syndrome has been successfully treated with injections of botulinum toxin A.<ref name="pmid9403490">{{cite journal| author=Naumann M, Zellner M, Toyka KV, Reiners K| title=Treatment of gustatory sweating with botulinum toxin. | journal=Ann Neurol | year= 1997 | volume= 42 | issue= 6 | pages= 973-5 | pmid=9403490 | doi=10.1002/ana.410420619 | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=9403490  }} </ref>,<ref name="pmid11042557">{{cite journal| author=von Lindern JJ, Niederhagen B, Bergé S, Hägler G, Reich RH| title=Frey syndrome: treatment with type A botulinum toxin. | journal=Cancer | year= 2000 | volume= 89 | issue= 8 | pages= 1659-63 | pmid=11042557 | doi= | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=11042557  }} </ref>
[[Complications]] of surgical treatment for [[parotid]] [[neoplasms]] include [[facial nerve]] dysfunction and frey syndrome, also known as [[gustatory]] flushing or [[Auriculotemporal nerve|auriculotemporal]] syndrome. Frey syndrome has been successfully treated with injections of [[Botulinum toxin|botulinum toxin A]].


==References==
== References ==
{{reflist|2}}
{{reflist|2}}


{{Epithelial neoplasms}}
{{Epithelial neoplasms}}


[[Category:Types of cancer]]
[[Category: Types of cancer]]
[[Category:Oral pathology]]
[[Category: Oral pathology]]


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Latest revision as of 16:05, 24 October 2019

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Ramyar Ghandriz MD[2]

Overview

Acinic cell carcinoma (ACC) is a low-grade malignant salivary neoplasm that constitutes approximately 17% of primary salivary gland malignancies. In the head and neck region, the parotid gland is the predominant site of origin. This tumor is usually a low-grade, highly differentiated carcinoma. Women are usually more frequently diagnosed than men. There are many risk factors, including cigarette smoking, genetic predisposition, radioactive substances, viral infections, rubber manufacturing, plumbing equipment and some types of woodworking, as well as asbestos mining and exposure to nickel compounds. Patients typically present with a slowly enlarging mass in the parotid region, nausea, vomiting and digestion problems. Treatments include complete surgical resection, chemotherapy, and radiation therapy. Acinic cell carcinoma was considered as a benign neoplasm until 1953. All acinic cell carcinomas were classified as neoplasms in the WHO's international classification of disease for oncology by 1972. In a second edition, all acinic cell carcinomas considered as adenocarcinoma by 1990. Batsakis et al, described acinic cell carcinoma as a derivative from progenitor reserve cells of terminal tubules and intercalated ducts of salivary tissue for the first time. Acinic cell carcinoma, a salivary gland tumor, mainly develop in parotid gland (81000 out of 100000), less common, it occurs in the submandibular gland and minor salivary glands of palate. It belongs to the family of adenocarcinoma which share similarities with: Adenoid cystic, Muco-epidermoid, low-grade adenocarcinoma and some breast cancers. The development of acinic cell carcinomas is the result of multiple genetic mutations that suggest association of tumor suppression genes such as: Chromosome 5q, chromosome 6p, chromosome 17p, deletions of chromosome 6q, loss of chromosome Y, Trisomy 21. Molecular studies suggest that retinoblastoma pathway also can be involved with acinic cell carcinomas. Acinic cell carcinoma is a head and neck tumor happening in the salivary glands. If a patient was observed with related signs, the tumor must be classified as a benign or invasive by the capsule being intact. Differential diagnosis of a malignant tumor in salivary gland is made after the incision and by histology features which will provide a good chemotherapy regimen for so called patients. In western countries, salivary gland carcinomas account for 4000 out of 100000 of all head and neck carcinomas, and approximately 80% of those occurring in parotid gland. one out of six parotid gland cancer is acinic cell carcinomas. Distribution of acinic cell carcinoma between age groups seems to be quiet even, with a median age of 52 years, but it occurs mostly at a younger age. Children are rarely affected with salivary gland carcinoma, but if they are, it is most likely to be acinic cell carcinoma. Acinic cell carcinoma is predominantly seen in in whites (85000 out of 100000 cases) and less in African nations(8000 out of 100000 cases) here is a higher incidence among female with the ratio ranging from 1.43:1 to 1.57:1. There is very little approved information about acinic cell carcinoma risk factors but familial predisposition and previous radiation exposure may play an important role. Screening is not recommended for acinic cell carcinoma. Once diagnosis confirmed, ultrasonography, nuclear scans, CT scan and MRI can usually conduct for assessing the size of the tumor, location, and the nature of the tumor. Parotid gland, is the most common site for acinic cell carcinoma affection. Typically, acinic cell carcinoma is a slow growing mass, lacking other symptoms. Pain or fixation to surroundings is a sign of poor prognosis. Nodal metastasis of acinic cell carcinoma is extremely rare. Another rare complication is cranial nerve VII dysfunction. A small minority of of acinic cell carcinoma occurs in sinonasal area or larynx, there is a big controversy about bilateral acinic cell carcinoma, it is still unknown if it invades bilateral glands or just a unilateral tumor. Common sites for non-salivary acinic cell carcinoma is lacrimal gland, pancreas, and breast. Acinic cell carcinoma in pancreas are so called as acinar cell carcinoma. The prognostic factors are age, pain, gender, race, previous inadequate treatment, extent of disease and invasion of the skull base. Physical examination of neck may reveal a firm swelling and tenderness. Clinical stage, particularly tumor size, may be the critical factor to determine the outcome of salivary gland cancer and may be more important than histologic grade. TNM system is the system of choice for studying acinic cell carcinoma. Acinic cell carcinoma is usually anatomically accessible tumor and patient do not show far metastasis at the time of diagnosis, the treatment of choice is surgery with resection of all free margins. Since acinic cell carcinoma could be neglected, a high rate of recurrence after first resection have been reported. Low grade acinic cell carcinoma will be cured with surgery alone, but the site of origin indicates extension of resection. Superficial parotidectomy often effects complete removal of acinic cell carcinoma, but conservative parotidectomy is indicated if the deep lobe is involved. Initial approach would be more aggressive if the tumor is locally advanced acinic cell carcinoma, the facial nerve cannot be preserved, it must be resected and reconstructed with an autograft from greater auricular or sural nerve. Elective neck dissection is not recommended in acinic cell carcinoma, because of low risk of regional lymph node metastasis. However studies have revealed additional neck dissection decrease the rate of recurrence.

Historical Perspective

Acinic cell carcinoma was discovered as a benign neoplasm until 1953.

All acinic cell carcinomas were classified as neoplasms in the WHO's international classification of disease for oncology by 1972. In a second edition, all acinic cell neoplasms considered as adenocarcinoma by 1990. Batsakis et al, described acinic cell carcinoma as a derivative from progenitor reserve cells of terminal tubules and intercalated ducts of salivary tissue for the first time.

Pathophysiology

Acinic cell carcinoma, a salivary gland tumor, mainly develop in parotid gland (81000 out of 100000), less common. Acinic cell carcinoma occurs in the submandibular gland and minor salivary glands of palate. Acinic cell carcinoma belongs to the family of adenocarcinoma with similarities like: Adenoid cystic, Muco-epidermoid, low-grade adenocarcinoma, some breast cancers. The development of acinic cell carcinoma is the result of multiple genetic mutations that suggest association of tumor suppression genes such as: chromosome 5q, chromosome 6p, chromosome 17p, deletions of chromosome 6q, loss of chromosome Y, Trisomy 21, molecular studies suggest that retinoblastoma pathway also can be involved with acinic cell carcinoma.

Differential diagnosis

Acinic cell carcinoma is a head and neck tumor happening in the salivary glands. If a patient was observed with related signs, the tumor must be classified as a benign or invasive by the capsule being intact. Differential diagnosis of a malignant tumor in the salivary gland is made after the incision and by histology features which will provide a good chemotherapy regimen for so-called patients.

Epidemiology and demographics

In western countries, salivary gland carcinomas account for 4000 out of 100000 of all head and neck carcinomas, and approximately 80% of those occurring in parotid gland. One out of six parotid gland cancer is acinic cell carcinoma. Distribution of acinic cell carcinoma between age groups seems to be quiet even, with a median age of 52 years, but it occurs mostly at a younger age. Children are rarely affected with salivary gland carcinoma, but if they are it is most likely to be acinic cell carcinoma. Acinic cell carcinoma is predominantly seen in whites (85000 out of 100000 cases) and less in African nations(8000 out of 100000 cases)here is a higher incidence among female with the ratio ranging from 1.43:1 to 1.57:1.

Risk factors

There is very little approved information about acinic cell carcinoma risk factors but familial predisposition and previous radiation exposure may play an important role.

Screening

There is insufficient evidence to recommend routine screening for acinic cell carcinoma. Once diagnosis confirmed, ultrasonography, nuclear scans, CT scan and MRI can usually conduct for assessing the size of the tumor, location, and the nature of the tumor.

Natural history, prognosis and complications

Parotid gland, is the most common site for acinic cell carcinoma affection. typically, acinic cell carcinoma is a slow-growing mass, lacking other symptoms. pain or fixation to surroundings is a sign of poor prognosis. nodal metastasis of acinic cell carcinoma is extremely rare. another rare complication is cranial nerve VII dysfunction. a small minority of acinic cell carcinoma occurs in sinonasal area or larynx. there is a big controversy about bilateral acinic cell carcinoma, it is still unknown if it invades bilateral glands or just a unilateral tumor. common sites for non-salivary acinic cell carcinoma is lacrimal gland, pancreas, and breast. Acinic cell carcinoma in the pancreas are so-called acinar cell carcinoma. the prognostic factors are age, pain, gender, race, previous inadequate treatment, the extent of disease, invasion of the skull base.

Physical Examination

Physical examination of neck may reveal a firm swelling and tenderness.

Staging

Clinical stage, particularly tumor size, maybe the critical factor to determine the outcome of salivary gland cancer and maybe more important than a histologic grade. TNM system is the system of choice for studying acinic cell carcinoma.

Treatment

Acinic cell carcinoma is usually anatomically accessible tumor and patient do not show far metastasis at the time of diagnosis, the treatment of choice is surgery with resection of all free margins. Since acinic cell carcinoma could be neglected, a high rate of recurrence after first resection have been reported. low grade acinic cell carcinoma will be cured with surgery alone, but the site of origin indicates extension of resection. Superficial parotidectomy often effects complete removal of acinic cell carcinoma, but conservative parotidectomy is indicated if the deep lobe is involved. Initial approach would be more aggressive if the tumor is locally advanced acinic cell carcinoma, the facial nerve cannot be preserved, it must be resected and reconstructed with an autograft from greater auricular or sural nerve. Elective neck dissection is not recommended in acinic cell carcinoma, because of low risk of regional lymph node metastasis. However studies have revealed additional neck dissection decrease the rate of recurrence.

Follow-up after treatment

Complications of surgical treatment for parotid neoplasms include facial nerve dysfunction and frey syndrome, also known as gustatory flushing or auriculotemporal syndrome. Frey syndrome has been successfully treated with injections of botulinum toxin A.

References

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