胃癌を伴う悪性黒色表皮腫の1例

Acanthosis Nigricans Associated with Gastric Cancer, Report of a Case

　黒色表皮腫（acanthosis nigricans；以下AN）は，皮膚の乳頭状増殖，色素沈着，角質増殖をtriasとした皮膚疾患であり，約半数に悪性腫瘍を合併し，その悪性腫瘍のうちほとんどは胃癌と言われている．われわれは胃癌を合併した悪性黒色表皮腫（malignant acanthosis nigricans；以下MAN）を4例経験したので報告する．

　A 62 year-old man was admitted to our hospital with a complaint of epigastralgia and skin hyperpigmentation. On physical examination, hyperpigmentation and verrucous protrusions were seen in his face, neck, axilla and perineum. Oral mucosa was also involved with papillomatous changes and fist sized tumor was palpable in his epigastric region Laboratory examination revealed iron deficiency anemia and hypoproteinemia. By x-ray and endoscopic examinations of the stomach, advanced gastric cancer simulating type Ⅱc+Ⅱa was detected in the antrum spreading to the middle gastric body.

　Histologically skin lesion was hyperkeratosis and papillomatosis, therefore the lesion was diagnosed as acanthosis nigricans. He was diagnosed to have malignant acanthosis nigricans associated with gastric cancer and was operated on. At laparotomy liver metastasis and remarkable lymph nodes metastasis were found, so curative operation could not be performed. Histological findings of the gastric lesion showed poorly differentiated adenocarcinoma, infiltrating to the proper muscular layer and the extent of lymph nodes metastasis was N₃(+). After the operation skin lesion was improved, but at four months after the operation he died of recurred cancer. We experienced four cases of malignant acanthosis nigricans associated with gastric cancer including this one in our hospital. All four cases were associated with advanced gastric cancers and were poorly differentiated adenocarcinoma histologically. Two cases including this one were operated, but the operations were not curative. All four cases died within one year after appearance of skin lesion. In three cases out of four, skin lesion improved by operation or chemotherapy.