放射線単独療法が奏効した前腕のメルケル細胞癌の1例

抄録

We report a case of an 88 year-old man with Merkel cell carcinoma. He noticed a subcutaneous induration on his left antebrachium about three months before visiting Tokoname municipal hospital. The tumor was firm, light red, dome-shaped with the size of 25×25mm in diameter. The biopsy specimen revealed nests of tumor cells with round nuclei and poor cytoplasm localized in the middle dermis to subcutaneous fatty tissue and did not extend into the epidermis. Electron microscopy demonstrated dense core granules in the intracellular spaces of the tumor cells. From the features mentioned above, we diagnosed his nodule as Merkel cell carcinoma. We chose the treatment of electron beam therapy (6MeV) alone to the primary lesion and left axillary lymph nodes in place of surgical treatment because of his age and past history of myocardial infarction. The tumor completely disappeared when the total amount of irradiation had been 51 Gy. We reviewed 46 reported cases of Merkel cell carcinoma located in the extremity and discussed the effectiveness of radiotherapy alone carried out in 12 reported cases with the tumor in Japan. [Skin Cancer (Japan) 2000; 15: 168-174]