Aspiration cytopathology of middle-ear neuroendocrine carcinoma

Primary neuroendocrine carcinoma (carcinoid tumor) is among the rarest of middle-ear (ME) neoplasms, with only a rare case of metastatic disease having been reported. Fine-needle aspiration biopsy (FNAB) was performed in a 51-yr-old male with a two-decade history of multiple local recurrences from a right middle-ear neoplasm, with the most recent surgical excision 2 yr ago. He currently presented with an enlarged right parotid gland, and a right infratemporal mass. Aspirate smears showed a monotonous population of cytologically bland cells with a small to moderate amount of pale granular cytoplasm, round to oval nuclei, inconspicuous nucleoli, and finely granular chromatin. Rare, isolated large cells were occasionally seen. Immunohistochemical staining of the cell block made from the aspirated material showed strong cytoplasmic positivity for chromogranin, synaptophysin, neuron-specific enolase (NSE), serotonin, and cytokeratin cocktail, and negative staining for S100 protein. Review of tissue slides from the patient's prior middle-ear tumor showed an identical immunoprofile and morphology, and led to a revision of the original diagnosis of paraganglioma. Middle-ear neuroendocrine carcinoma has a low but definite metastatic potential, which can be diagnosed using FNAB if ancillary immunohistochemical studies are available.