Mixed adenoneuroendocrine carcinoma of the tongue arising within a congenital enteric cyst.

BACKGROUND: Primary intestinal-type adenocarcinoma of the tongue is rare. This represents the first reported case of a primary mixed adenoneuroendocrine carcinoma (MANEC) of the tongue arising within a congenital enteric cyst.

METHODS: A 52-year-old man presented with a midline tongue mass that was connected to the mucosal surface with an epithelial-lined sinus tract. Morphological examination and immunohistochemical profiling of the neoplasm were performed.

RESULTS: Histopathological evaluation showed a primary MANEC arising within a preexisting congenital enteric cyst, comprising both adenocarcinoma and neuroendocrine components. The adenocarcinoma had a colonic-type morphology and coexpressed CK7, CK20, and CDX2. Imaging and colonoscopy excluded a distant primary colorectal neoplasm.

CONCLUSION: The association of primary MANEC of the tongue with a gastrointestinal heterotopic cyst supports an origin from entrapped endodermal elements as opposed to salivary duct origin. This case raises the awareness of a rare yet prognostically important complication of a gastrointestinal heterotopic cyst.