Calcitonin-Secreting Neuroendocrine Carcinoma of Larynx with Metastasis to Thyroid

Abstract

Primary neuroendocrine tumors of the larynx are rare, with moderately differentiated neuroendocrine carcinoma (MDNC) being the most frequent histologic type. We report a MDNC in a 57-year-old gentleman with an enlarging right-sided neck mass. Flexible fiberoptic exam revealed a right arytenoid lesion. Histology from excisional biopsy was concerning for medullary thyroid carcinoma (MTC) versus NET of the larynx. Immunohistochemistry was diffusely positive for calcitonin and CEA and focally positive for TTF-1. Serum calcitonin was elevated. Thyroid ultrasound was unremarkable. The patient underwent laryngectomy, thyroidectomy, and neck dissection. Pathology showed neuroendocrine carcinoma of right arytenoid with positive cervical lymph nodes. A 4 mm deposit of NET was present in right thyroid with adjacent intravascular tumor consistent with thyroidal metastasis from a primary laryngeal NET (MDNC). MDNC and MTC can be microscopically indistinguishable. Both tumors can stain positively for calcitonin and CEA. TTF-1 staining has been useful to help distinguish these tumors as it is strongly and diffusely positive in MTC, but usually negative (or only focally positive) in MDNC. We report the fourth case of primary neuroendocrine carcinoma of the larynx associated with elevated serum calcitonin level and the first such case associated with metastasis to the thyroid.

Metastatic medullary thyroid carcinoma or calcitonin‐secreting carcinoid tumor of lung? A diagnostic dilemma in a patient with lung mass and thyroid nodule

“…LaBryer et al reported a case of calcitonin secreting neuroendocrine tumor of the larynx with elevated serum calcitonin. In the total thyroidectomy specimen a 4 mm calcitonin positive neuroendocrine carcinoma was identified which was consistent with thyroid metastasis from a primary laryngeal NET . In the three other cases of calcitonin secreting NET of larynx reported by Sweeney et al, Smets et al and Insabato et al, the patients underwent thyroidectomy in all three instances with no evidence of medullary thyroid carcinoma.…”

“…Calcitonin‐secreting neuroendocrine tumors outside the thyroid gland are rare. These tumors have been reported in literature as case reports in various organs including lung, pancreas, larynx, bladder and ovary . The frequency of calcitonin secreting neuroendocrine tumors in various organs may be underestimated, as serum calcitonin measurement or immunohistochemical stains for calcitonin is not routinely performed on neuroendocrine tumors of various organs.…”

“…These tumors have been reported in literature as case reports in various organs including lung, pancreas, larynx, bladder and ovary. [3][4][5][6][7][8] The frequency of calcitonin secreting neuroendocrine tumors in various organs may be underestimated, as serum calcitonin measurement or immunohistochemical stains for calcitonin is not routinely performed on neuroendocrine tumors of various organs. Here, we report a rare case of calcitonin-secreting tumor of the lung which was detected as an incidental finding on imaging studies.…”

The Bethesda System for Reporting Thyroid Cytopathology: Proposed Modifications and Updates for the Second Edition from an International Panel

“…Additional descriptors pertaining to rare morphologic variants of MTC (e.g., small cell, giant cell) that can be diagnostically challenging would be useful [43,44]. Other diagnostic pitfalls that could be addressed include: (1) Morphological overlap with oncocytic follicular lesions and PDTC [45]; and (2) Morphological and immunohistochemical overlap with other neuroendocrine tumors [46]. In addition, some aspects of the management of MTC have been updated in the 2015 revised ATA guidelines [41].…”

Metastatic Moderately Differentiated Neuroendocrine Carcinoma Of The Larynx Mimicking Medullary Thyroid Cancer

“…There are also sporadic reports of MDNC metastasizing to the lung, liver, and brain (10). There is 1 case report of MDNC metastasizing to the thyroid, but the authors questioned the diagnosis due to the presence of thyroid C-cell hyperplasia (4).…”