An Esophageal Collision Tumor

Department of Surgery, Tokyo Metropolitan Tama Medical Center, Tokyo, Japan. Electronic address: .
Clinical gastroenterology and hepatology: the official clinical practice journal of the American Gastroenterological Association (Impact Factor: 7.9). 08/2013; 12(3). DOI: 10.1016/j.cgh.2013.08.016
Source: PubMed


An esophageal collision tumor is a rare situation that shows different neoplasms growing independently and simultaneously in close proximity until they become juxtaposed; however it should be rigorously distinguished from mixed or composite tumors in which one neoplastic clone diverges into two cell lineages that actually intermingle. The aim of this report is to clarify the clinicopathological feature of the esophageal collision tumor.
We investigated an esophageal collision tumor which was surgically resected. The esophageal lesion showed histologic heterogeneity. It harbored a component of squamous cell carcinoma in situ and a small blue cell tumor. The former was located in the lamina propria and the latter, in the submucosa. The small cellular component immunohistochemically exhibited the neuroendocrine phenotypes. The Ki-67 index of this element exceeded 80%. The interface between these two elements was abrupt. These pathological findings unmistakably met these rigorous criteria for a collision tumor including the neuroendocrine carcinoma and squamous cell carcinoma.
Although the exact oncogenic mechanism or the interaction of two independent neoplasms still remains unclear, further investigation such as electron microscopic features and genetic analysis of microsatellite instability may all aid in elucidating the pathomechanism of colliding tumors.

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Available from: Kensuke Adachi, Mar 31, 2014