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.
Highlights
Neuroendocrine tumors of the larynx are rare, accounting for ∼0.6% of laryngeal neoplasms [1]
A 4 mm calcitonin-positive deposit of neuroendocrine carcinoma was present in right upper pole of the thyroid with adjacent intravascular tumor consistent with thyroidal metastasis from a primary laryngeal NET
Neuroendocrine tumors of the larynx are rare, with just over 500 cases recorded in the literature since initially described by Goldman et al in 1969 [11]
Summary
Neuroendocrine tumors of the larynx are rare, accounting for ∼0.6% of laryngeal neoplasms [1]. MDNC of the larynx and medullary thyroid carcinoma (MTC) demonstrate similar morphological features and can be microscopically indistinguishable, when presenting as metastasis [4]. Both tumors stain positively for calcitonin and CEA. To the best of our knowledge, only 3 cases of neuroendocrine carcinoma of the larynx with elevated serum calcitonin have been reported [5,6,7]. We report the fourth case of primary calcitonin-producing neuroendocrine tumor of the larynx. There are
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