Hamartoma pathophysiology

Jump to navigation Jump to search

Hamartoma Microchapters

Home

Patient Information

Overview

Historical Perspective

Classification

Pathophysiology

Causes

Differentiating Hamartoma from other Diseases

Epidemiology and Demographics

Risk Factors

Screening

Natural History, Complications and Prognosis

Diagnosis

Diagnostic Study of Choice

Staging

History and Symptoms

Physical Examination

Laboratory Findings

Electrocardiogram

Chest X Ray

CT

MRI

Ultrasound

Other Imaging Findings

Other Diagnostic Studies

Treatment

Medical Therapy

Surgery

Primary Prevention

Secondary Prevention

Cost-Effectiveness of Therapy

Future or Investigational Therapies

Case Studies

Case #1

Hamartoma pathophysiology On the Web

Most recent articles

Most cited articles

Review articles

CME Programs

Powerpoint slides

Images

American Roentgen Ray Society Images of Hamartoma pathophysiology

All Images
X-rays
Echo & Ultrasound
CT Images
MRI

Ongoing Trials at Clinical Trials.gov

US National Guidelines Clearinghouse

NICE Guidance

FDA on Hamartoma pathophysiology

CDC on Hamartoma pathophysiology

Hamartoma pathophysiology in the news

Blogs on Hamartoma pathophysiology

Directions to Hospitals Treating Hamartoma

Risk calculators and risk factors for Hamartoma pathophysiology

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]Associate Editor(s)-in-Chief: Maria Fernanda Villarreal, M.D. [2] Vamsikrishna Gunnam M.B.B.S [3]

Overview

Hamartomas usually arise from connective tissue and are generally composed of cartilage, fat, and connective tissue cells. Hamartomas can be found in the lungs (most common), heart, hypothalamus, kidneys, or spleen. The pathogenesis primarily consist of disorganized replication of normal tissue cells. Many hereditary syndromes are associated with hamartomatous formation. These include Peutz-Jeghers syndrome, PTEN hamartoma tumor syndrome, and Cowden's syndrome. Genes that are involved in the pathogenesis of hamartomatous syndromes include BMPR1A, SMAD4, PTEN, and STK11.

Pathophysiology

Pathogenesis

  • Hamartomas occur in the same location as the normal tissue (in the tissue of its origin) as opposed to choristomas, which grow in other tissues (different from its origin).
  • The pathogenesis primarily consists of disorganized replication of normal tissue cells. The underlying mechanisms for the replication abnormality are not fully understood.[1]
  • Hamartomas arise from connective tissue and are generally formed of cartilage, fat, and connective tissue cells, although they may include many other types of cells.
  • Hamartomas grow at the same rate as the normal cells of the organ.[2]
  • These can be located in the lungs (most common), heart, hypothalamus, kidneys, or spleen.[1]

Bone-forming tumors

Cartilage-forming tumors

  • It is understood that cartilage-forming tumors like osteochondroma is produced from abnormal cartilaginous epiphyseal growth plate tissue and abnormal regulation of cartilage proliferation.[6][7][8]
  • Cartilage-forming tumors are termed as congenital error of epiphyseal development.

Fiber-forming tumors

  • It is understood that fiber-forming tumors is produced from continued growth of fibrous cortical defects that extrude into the medullary cavity.
  • The most commonly involved bone are tibia and the femur.

Lung

  • Lung hamartomas mostly arise from connective tissue and are generally formed of cartilage, fat, and connective tissue cells, although they may include many other types of cells.
  • About 5-8% of all solitary lung tumors and about 75% of all benign lung tumors are hamartomas.
  • The majority of pulmonary hamartomas form from connective tissue on the outside of the lungs, although about 10% form in the linings of the bronchi.
  • In the majority of patients, it can be difficult to distinguish hamartoma from malignancies.[2]
  • Pulmonary hamartomas can be divided into two subtypes endobronchial and parenchymal.
  • An endobronchial location is described in 3%–20% of all pulmonary hamartomas. This subtype is mainly composed of cartilage and fibrous tissue.
  • Endobronchial hamartomas typically contain more fat tissue than parenchymal hamartomas.

Heart

  • Cardiac rhabdomyomas are hamartomas comprised of altered cardiac myocytes that contain large vacuoles and glycogen.
  • Cardiac hamartomas arises from the striated muscle cells (cardiac myocytes), which are normally involved in the coordinated contractions of cardiac muscle cells.
  • Development of cardiac hamartomas is the result of multiple genetic mutations.
  • Mutations in the TSC1 or TSC2 genes are related with tuberous sclerosis.
  • There is a strong association between cardiac rhabdomyomas and tuberous sclerosis (characterized by hamartomas of the central nervous system, kidneys and skin, as well as pancreatic cysts; 25-50% of patients with cardiac rhabdomyomas will have tuberous sclerosis.
  • Cardiac hamartoma symptoms will depend on the size of the tumor and location relative to the conduction system.
  • For more information on heart hamartoma, See here.

Hypothalamus

Kidneys, spleen, and other vascular organs

Genetics

  • Genes involved in the pathogenesis of harmatomatous syndromes include:[9]

Associated Conditions

Gross Pathology

  • On gross pathology, a hallmark feature of hamartoma is a well-circumscribed mass that may show a variegated yellow and white appearance, which corresponds to fat and cartilage, respectively.[11]
  • Hamartomas are unencapsulated, lobulated tumors with connective tissue septa.
  • Tumor size ranges between 1 and 3 cm in diameter at the time of diagnosis.

Microscopic Pathology

  • On microscopic pathology, hamartomas have benign tumors features such as disorganized (non-neoplastic) growth, tissue of the region within it is found, and no invasion to surrounding tissue or structures.[11]
  • Common findings include:
  • Cartilage single cells in lacunae surrounded by abundant matrix and paucicellular vis-a-vis malignant lesions
  • Fat (adipocytes)
  • Respiratory epithelium (columnar epithelium with cilia), only present in lung hamartoma

Gallery

References

  1. 1.0 1.1 1.2 Splenic hamartoma.Dr Henry Knipe et al Radiopedia.http://radiopaedia.org/articles/pulmonary-hamartoma-1 Accessed on December 09, 2015
  2. 2.0 2.1 Zakharov V, Schinstine M (2008). "Hamartoma of the lung". Diagn. Cytopathol. 36 (5): 331–2. doi:10.1002/dc.20790. PMID 18418855.
  3. McCarthy EF, Dorfman HD (June 1980). "Vascular and cartilaginous hamartoma of the ribs in infancy with secondary aneurysmal bone cyst formation". Am. J. Surg. Pathol. 4 (3): 247–53. PMID 7396066.
  4. Balci P, Obuz F, Göre O, Yilmaz E, Demirpolat G, Aktug T, Kovanlikaya I (September 1997). "Aneurysmal bone cyst secondary to infantile cartilaginous hamartoma of rib". Pediatr Radiol. 27 (9): 767–9. doi:10.1007/s002470050224. PMID 9285745.
  5. Cohen MC, Drut R, Garcia C, Kaschula RO (1992). "Mesenchymal hamartoma of the chest wall: a cooperative study with review of the literature". Pediatr Pathol. 12 (4): 525–34. PMID 1409151.
  6. McCarthy EF, Dorfman HD (June 1980). "Vascular and cartilaginous hamartoma of the ribs in infancy with secondary aneurysmal bone cyst formation". Am. J. Surg. Pathol. 4 (3): 247–53. PMID 7396066.
  7. Balci P, Obuz F, Göre O, Yilmaz E, Demirpolat G, Aktug T, Kovanlikaya I (September 1997). "Aneurysmal bone cyst secondary to infantile cartilaginous hamartoma of rib". Pediatr Radiol. 27 (9): 767–9. doi:10.1007/s002470050224. PMID 9285745.
  8. Göre O, Kiliçalp A, Başdemir G, Ozer E, Aktuğ T (1999). "Cartilaginous hamartoma of the chest wall with secondary aneurysmal cyst-like areas in an infant: a case report". Turk. J. Pediatr. 41 (1): 139–42. PMID 10770690.
  9. Stojcev Z, Borun P, Hermann J, et al. Hamartomatous polyposis syndromes. Hered Cancer Clin Pract. 2013;11(1):4.
  10. Liaw D, Marsh DJ, Li J, Dahia PL, Wang SI, Zheng Z; et al. (1997). "Germline mutations of the PTEN gene in Cowden disease, an inherited breast and thyroid cancer syndrome". Nat Genet. 16 (1): 64–7. doi:10.1038/ng0597-64. PMID 9140396.
  11. 11.0 11.1 Kumar V, Abbas AK, Aster JC. Robbins Basic Pathology. Elsevier Health Sciences; 2012.
  12. 12.0 12.1 12.2 12.3 Hamartoma. Libre Pathology.http://librepathology.org/wiki/index.php/Pulmonary_hamartoma Accessed on December 8, 2015


Template:WikiDoc Sources