Melanotic Xp11-associated tumor of the sigmoid colon:A case report  

作　　者：Gang Wang Gang-Gang Li Sheng-Mao Zhu Bao-Jia Cai Peng-Jie Yu Cheng-Wu Zhang 

机构地区：[1]the Graduate School of Qinghai University [2]Department of Gastrointestinal Surgery, Affiliated Hospital of Qinghai University

出　　处：《World Journal of Clinical Cases》2019年第5期684-690,共7页世界临床病例杂志

基　　金：Supported by The Key Research & Development and Transformation Project of Qinghai Province for 2018(No.2018-SF-113)

摘　　要：BACKGROUND Melanotic Xp11-associated tumors are rare mesenchymal-derived tumors. So far,most primary melanotic Xp11-associated tumors have been reported in the kidney, and reports of this tumor in the gastrointestinal tract are rare.CASE SUMMARY Here we describe the case of a 25-year-old woman who presented with a melanotic Xp11-associated tumor in the sigmoid colon. Colonoscopy revealed a large mucosal bulge in the sigmoid colon, approximately 32 cm inside the anus.The surface was rough with local erosion. The tumor was brittle on biopsy and bled easily. Computed tomography revealed thickening of the rectal wall with edema. Postoperative pathology indicated the likelihood of a perivascular epithelioid cell tumor. Histologically, the tumor comprised plump epithelioid cells with abundant clear to lightly eosinophilic cytoplasm and round nuclei arranged in an alveolar or trabecular pattern. The tumor cells were strongly positive for HMB-45, Melan-A, Cathepsin K, and TFE3 but negative for vimentin,smooth muscle actin, S100 protein, CD10, CK20, and desmin. The tumor cells had a low Ki-67 labeling index(approximately 2%). Fluorescence in situ hybridization revealed TFE3 fracture. Based on these histologic and immunohistochemical features, a diagnosis of melanotic Xp11-associated tumor of the sigmoid colon was made.CONCLUSION In summary, we report the clinicopathological features of a primary tumor that is extremely rare in the sigmoid colon and review the clinicopathological characteristics of melanotic Xp11-associated tumors, compatible with the very rare tumor termed "melanotic Xp11 translocation renal cancer" in all aspects.BACKGROUND Melanotic Xp11-associated tumors are rare mesenchymal-derived tumors. So far,most primary melanotic Xp11-associated tumors have been reported in the kidney, and reports of this tumor in the gastrointestinal tract are rare.CASE SUMMARY Here we describe the case of a 25-year-old woman who presented with a melanotic Xp11-associated tumor in the sigmoid colon. Colonoscopy revealed a large mucosal bulge in the sigmoid colon, approximately 32 cm inside the anus.The surface was rough with local erosion. The tumor was brittle on biopsy and bled easily. Computed tomography revealed thickening of the rectal wall with edema. Postoperative pathology indicated the likelihood of a perivascular epithelioid cell tumor. Histologically, the tumor comprised plump epithelioid cells with abundant clear to lightly eosinophilic cytoplasm and round nuclei arranged in an alveolar or trabecular pattern. The tumor cells were strongly positive for HMB-45, Melan-A, Cathepsin K, and TFE3 but negative for vimentin,smooth muscle actin, S100 protein, CD10, CK20, and desmin. The tumor cells had a low Ki-67 labeling index(approximately 2%). Fluorescence in situ hybridization revealed TFE3 fracture. Based on these histologic and immunohistochemical features, a diagnosis of melanotic Xp11-associated tumor of the sigmoid colon was made.CONCLUSION In summary, we report the clinicopathological features of a primary tumor that is extremely rare in the sigmoid colon and review the clinicopathological characteristics of melanotic Xp11-associated tumors, compatible with the very rare tumor termed "melanotic Xp11 translocation renal cancer" in all aspects.

关 键 词：Melanotic Xp11-associated TUMOR PERIVASCULAR EPITHELIOID cell TUMOR MELAN-A SIGMOID colon Case report 

分 类 号：R[医药卫生]