WBR1150
| Author | PageAuthor::Vendhan Ramanujam |
|---|---|
| Exam Type | ExamType::USMLE Step 3 |
| Main Category | MainCategory::Community Medical Health Center, MainCategory::Primary Care Office |
| Sub Category | SubCategory::Endocrine, SubCategory::Oncology |
| Prompt | [[Prompt::A 60 year old Caucasian woman presents to the clinic with a complaint of swelling in front of her neck which she noticed recently. She denies any history suggestive of either hyper or hypothyroidism. She denies any history of fever, neck pain, difficulty in breathing or swallowing and any recent change in her voice. She is currently not on any medications and neither has a history of exposure to radiation nor any family history of thyroid illness. On examination, her vital signs are blood pressure of 120/80 mmHg, pulse rate of 90 beats/min, respiratory rate of 12 breaths/min and temperature of 37° C. A 3 x 2 cm nodule is palpated in her right thyroid lobe. Lab tests revealed normal TSH levels. Fine needle aspiration cytology of the nodule and subsequent histopathological analysis revealed papillary carcinoma of the thyroid. She then underwent a near total thyroidectomy along with radioactive ablation and radioiodine scan. What is the next best step in management of this patient?]] |
| Answer A | AnswerA::CT neck and chest |
| Answer A Explanation | [[AnswerAExp::Incorrect - After diagnosing papillary carcinoma of thyroid with a histopathological analysis, ultrasound of the neck is the primary modality that is used for staging the disease. CT scan of the neck and the chest might be valuable only if the disease is recurrent or metastatic.]] |
| Answer B | AnswerB::High dose thyroxine |
| Answer B Explanation | [[AnswerBExp::Correct - Levothyroxine therapy will be the next best step following thyroidectomy and radioiodine ablation in the treatment of papillary carcinoma of thyroid in order to prevent hypothyroidism and to minimize the potential tumor regrowth due to TSH stimulation.]] |
| Answer C | AnswerC::Ultrasound of the thyroid bed |
| Answer C Explanation | [[AnswerCExp::Incorrect - After diagnosing papillary carcinoma of thyroid with a histopathological analysis, ultrasound of the neck is the primary modality that is used for staging the disease. It is not of much use following surgery and in the post operative follow up period.]] |
| Answer D | AnswerD::Follow up with regular calcitonin measurements |
| Answer D Explanation | [[AnswerDExp::Incorrect - Calcitonin measurements are specifically useful in detecting recurrence of medullary carcinoma of thyroid following surgery.]] |
| Answer E | AnswerE::Follow up with regular thyroglobulin measurements |
| Answer E Explanation | AnswerEExp::'''Incorrect''' - Thyroglobulin measurements are useful only after several weeks following total thyroidectomy to detect any recurrence and not immediately after the surgery. |
| Right Answer | RightAnswer::B |
| Explanation | [[Explanation::Papillary carcinoma is the most common type of thyroid cancer. It occurs more frequently in women and presents in the 30-40 year age group. It is also the predominant cancer type in children with thyroid cancer, and in patients with thyroid cancer who have had previous radiation to the head and neck (in this group, the cancer tends to be multifocal with early lymphatic spread, and portends a relatively poor prognosis). Thyroglobulin can be used as a tumor marker for well-differentiated papillary thyroid cancer.
Surgery is the primary mode of therapy for patients with papillary thyroid cancer. In minimal diseases (diameter up to 1.0 centimeters), hemithyroidectomy (or unilateral lobectomy) and isthmectomy may be sufficient. There is some discussion whether this is still preferable over total thyroidectomy for this group of patients. In gross diseases (diameter over 1.0 centimeters), total thyroidectomy, and central compartment lymph node removal is the therapy of choice. Total thyroidectomy reduces the risk of recurrence, avoids any residual disease since papillary carcinoma is a multifocal disease, allows easy monitoring with thyroglobulin since sensitivity for picking up recurrence is increased following total thyroidectomy, and allows for easy detection of metastatic disease by thyroid and neck node ultrasound. Post-thyroidectomy, radioiodine is used as an adjuvant in the ablation of residual thyroid tissue and possible microscopic residual cancer. It also serves in the detection of possible metastatic disease, and further treatment of known residual or metastatic thyroid cancer during follow up. Post-thyroidectomy, whether or not the patient receives radioiodine therapy, levothyroxine therapy is administered in all in order to prevent hypothyroidism and to minimize the potential tumor regrowth due to TSH stimulation. |
| Approved | Approved::Yes |
| Keyword | WBRKeyword::Papillary carcinoma of thyroid |
| Linked Question | Linked:: |
| Order in Linked Questions | LinkedOrder:: |