A 32-year-old woman with multiple endocrine neoplasia syndrome type 2A (MEN-2A) and carrier of a mutation in RET. In a neck ultrasound a 6 mm hypoechogenic nodule with calcifications inside is identified. It was decided to perform a total thyroidectomy and cervical lymph node removal. In the macroscopic study a total of three nodules were identified, two in the right lobe of 5 and 6 mm, and one in the left lobe of 4 mm. In the microscopic study the three lesions are constituted by a uniform proliferation of rounded cells arranged in a solid pattern and accompanied by calcifications and amyloid deposits. The nuclei are not clear, nor do they show clefts or pseudoinclusions. Immunohistochemical staining for synaptophysin is positive. In the cervical lymph node clearance metastases are identified. What is the pathologic diagnosis of the lesions identified in the total thyroidectomy?
Typical medullary thyroid RET (C cells, elevated calcitonin, inherited MEN-2nd, typical MIR question).
Multifocal medullary carcinoma.
Multifocal papillary carcinoma.
Follicular carcinoma.
Hyperplasia of parafollicular cells.
Typical medullary thyroid RET (C cells, elevated calcitonin, inherited MEN-2nd, typical MIR question).