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{{WBRQuestion
{{WBRQuestion
|QuestionAuthor=Vendhan Ramanujam
|QuestionAuthor=Vendhan Ramanujam
|ExamType=USMLE Step 3
|ExamType=USMLE Step 3

Latest revision as of 02:43, 28 October 2020

 
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, 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 symptoms. 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 thyroid. 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::'''Incorrect'''- Levothyroxine therapy is administered only after thyroidectomy in order to prevent hypothyroidism and to minimize the potential tumor regrowth due to TSH stimulation.
Answer C AnswerC::Radioactive iodine
Answer C Explanation [[AnswerCExp::Incorrect- Only after thyroidectomy, radioactive iodine is either used as an adjuvant in the ablation of residual thyroid tissue and possible microscopic residual cancer or to detect a metastatic disease and in the further treatment of the known residual or metastatic thyroid cancer during followup.]]
Answer D AnswerD::Total thyroidectomy
Answer D Explanation [[AnswerDExp::Correct-Total thyroidectomy is the preferred initial treatment of choice for both minimal (diameter up to 1.0 centimeters) as well as gross (diameter over 1.0 centimeters) papillary carcinoma of thyroid. It 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.]]
Answer E AnswerE::Subtotal thyroidectomy
Answer E Explanation [[AnswerEExp::Incorrect- In minimal diseases (diameter up to 1.0 centimeters), hemithyroidectomy (or unilateral lobectomy) and isthmectomy may be sufficient, but there is some discussion whether this is still preferable over total thyroidectomy for this group of patients.]]
Right Answer RightAnswer::D
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 followup. 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.
Educational Objective: Total thyroidectomy is the initial treatment of choice in the management of papillary carcinoma of thyroid along with an adjuvant radioiodine therapy for the ablation of residual thyroid tissue and possible microscopic residual cancer. Radioiodine is also used to detect a metastatic disease and in the further treatment of a known residual or metastatic thyroid cancer during followup. Post-thyroidectomy, whether or not the patient receives radioiodine therapy, levothyroxine therapy is administered in order to prevent hypothyroidism and to minimize the potential tumor regrowth due to TSH stimulation.
References: ]]

Approved Approved::Yes
Keyword WBRKeyword::Papillary carcinoma of thyroid
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