A case of large cell neuroendocrine carcinoma exhibiting rhabdoid features in the esophagogastric junction.

We report a case of large cell neuroendocrine carcinoma with rhabdoid features in the esophagogastric junction. An 81-year-old man presented to Saku Central Hospital Advanced Care Center with a tumor in the esophagogastric junction. During upper gastrointestinal endoscopy, an ulcerative tumor, measuring 4 × 3 cm in diameter, was observed. Computed tomography revealed lymph node metastasis, but no metastasis to other organs was observed. A thoracoscopic subtotal esophagectomy was performed. Histopathologically, anaplastic large cells exhibited a solid growth pattern with focal and geographic necrosis. Approximately half of the tumor cells exhibited large nuclei with conspicuous nucleoli; an eosinophilic "rhabdoid" cytoplasmic inclusion; and a nucleus displaced eccentrically by the cytoplasmic inclusion body. Immunohistochemically, tumor cells, including rhabdoid cells, were focally positive for pan-cytokeratin and diffusely positive for vimentin and synaptophysin. Additionally, electron microscopy identified dense-core granules in the tumor cells. Therefore, a diagnosis of large cell neuroendocrine carcinoma with rhabdoid features was made. A few cases of esophageal neuroendocrine tumors with rhabdoid features have been reported in the lung and pancreas; however, this is the first report of large cell neuroendocrine carcinoma with rhabdoid features in the esophagogastric junction.