Collision tumor of the stomach: an unusual combination of adenocarcinoma and immature "neuroepitheliomatous" teratoma.

A 54-year-old woman was diagnosed with an asymptomatic gastric tumor during routine radiological investigation for staging of breast carcinoma. Subsequent endoscopic biopsy confirmed a poorly differentiated adenocarcinoma. Surgical resection of the stomach showed a tumor with 2 distinct components: a superficial lymphoepithelioma-like adenocarcinoma and a deeper submucosal component consistent with immature teratoma. There was lymph node metastasis. The patient is well without any evidence of disease 18 months post surgery.