Serin Gürdeniz, Doğanavşargil Başak, Calişkan Cemil, Akalin Taner, Sezak Murat, Tunçyürek Müge
Department of Pathology, Ege University School of Medicine, Izmir, Turkey.
Turk J Gastroenterol. 2010 Mar;21(1):45-9. doi: 10.4318/tjg.2010.0048.
Gastrointestinal malignant melanomas, either primary or metastatic, are rare and overlooked tumors. There is also controversy regarding the actual existence of primary melanoma in the gastrointestinal tract apart from the esophagus and anorectal regions, where melanocytes normally exist. A case of malignant melanoma in the cecum is presented. The patient was a 30- year-old male who presented to the hospital for abdominal pain and diarrhea. The tumor was located mainly in the submucosa and measured 14x11x4.5 cm. The cut surface was solid, gray-white and fleshy. Histologically, tumor cells were arranged in compact nests or wide cords surrounded by fibrous stroma. The tumor cells had pleomorphic nuclei and quite rich cytoplasm; multinucleated, giant tumor cells were intermingled. Although no tumor cells contained apparent brown pigment, most were found to be positive for S-100 protein, HMB-45, Melan-A, and vimentin. The possibility of a metastatic lesion was considered. While the patient had a history of a pathologically examined dorsal nevus excision two years before, there was no evidence of either cutaneous or ocular primary melanoma at the time of diagnosis. Moreover, a thorough postoperative investigation did not reveal any other lesion in any other site favoring a metastatic spread. There was also no evidence of recurrent disease or metastasis one year after the surgery. This case is presented in view of its rare occurrence in the cecum. The difficulties in the diagnostic course are discussed, together with a literature review on distinguishing a primary mucosal melanoma from a metastatic one from an unknown or regressed cutaneous primary tumor.
胃肠道恶性黑色素瘤，无论是原发性还是转移性的，都是罕见且易被忽视的肿瘤。除了食管和肛管区域（正常存在黑素细胞）外，关于胃肠道原发性黑色素瘤的实际存在也存在争议。本文报告一例盲肠恶性黑色素瘤病例。患者为一名30岁男性，因腹痛和腹泻入院。肿瘤主要位于黏膜下层，大小为14×11×4.5 cm。切面实性，灰白色，质软。组织学上，肿瘤细胞呈紧密巢状或宽条索状排列，周围有纤维性间质。肿瘤细胞核呈多形性，细胞质相当丰富；多核巨细胞夹杂其中。虽然没有肿瘤细胞含有明显的棕色色素，但大多数被发现S-100蛋白、HMB-45、Melan-A和波形蛋白呈阳性。考虑为转移性病变的可能性。患者两年前有背部痣切除并经病理检查的病史，但诊断时没有皮肤或眼部原发性黑色素瘤的证据。此外，术后彻底检查未发现其他部位有任何有利于转移扩散的病变。术后一年也没有复发或转移的证据。鉴于其在盲肠中罕见，故报告此病例。讨论了诊断过程中的困难，并对区分原发性黏膜黑色素瘤与来自未知或消退性皮肤原发性肿瘤的转移性黑色素瘤进行了文献综述。
