Inoue Takuya, Misago Noriyuki, Narisawa Yutaka
Division of Dermatology, Department of Internal Medicine, Saga University, Saga, Japan.
J Cutan Pathol. 2007 Jun;34(6):508-12. doi: 10.1111/j.1600-0560.2006.00656.x.
Myxoid melanoma is a rare variant of malignant melanoma. The diagnostic problems are obviously increased when it presents as amelanotic metastasis in a lymph node. An 82-year-old woman presented a subcutaneous mass in the right axilla. A thorough clinical investigation disclosed a pigmented black lesion on the right forearm. The right axillary lymph nodes and the pigmented lesion were resected. In the lymph nodes, proliferation of tumor cells with an abundant mucous substrate was noted. The cells proliferated in a variable pattern, and there were no melanin granules detected on hematoxylin-eosin-stained sections. However, we found melanin granules in the tumor cells observed under electron microscopy. In the pigmented lesion of the right forearm, there were small clusters of tumor cells with melanin granules, suggesting malignant melanoma. In the present case, myxoid metastasis occurred with the partial spontaneous disappearance of the primary nonmyxoid malignant melanoma.
黏液样黑色素瘤是恶性黑色素瘤的一种罕见变体。当它以无色素性转移至淋巴结的形式出现时，诊断问题会明显增加。一名82岁女性右腋窝出现皮下肿块。全面的临床检查发现右前臂有一个黑色色素沉着病变。切除了右腋窝淋巴结和色素沉着病变。在淋巴结中，注意到肿瘤细胞在丰富的黏液基质中增殖。细胞以可变模式增殖，苏木精-伊红染色切片上未检测到黑色素颗粒。然而，我们在电子显微镜下观察的肿瘤细胞中发现了黑色素颗粒。在右前臂的色素沉着病变中，有小簇带有黑色素颗粒的肿瘤细胞，提示为恶性黑色素瘤。在本病例中，黏液样转移发生时，原发性非黏液样恶性黑色素瘤部分自发消失。
