広汎な肝転移と共に胃粘膜転移をきたした悪性黒色腫の1例

A CASE OF MALIGNANT MELANOMA METASTATIZING TO THE GASTRIC MUCOSA ASSOCIATED WITH EXTENSIVE LIVER METASTASIS

Ⅰ．緒言

　胃および小腸の悪性黒色腫（malignantmelanom）はまれな疾患であるがBanzetら¹⁾（1953）は文献から胃・小腸転移を伴ったmelanoblastoma70例を記載しており，Reedら²⁾によれば，1962年までに胃・小腸の悪性黒色腫の報告は100例に満たないという．これらの胃・小腸の悪性黒色腫は明らかな原発巣が不明なものもあるが，大部分は転移性のものと考えられている³⁾．

　一般に悪性腫瘍の血行性胃粘膜転移はまれなものとされているが，Bäckman³⁾によれば，その約1/4は悪性黒色腫の転移によるものであり，小腸の転移性腫瘍でも，同様にその1/4が悪性黒色腫であるという．

　Malignant melanoma of the stomach is a disease of rare occurrence. According to Reed et al. only less than 100 cases have been reported up to 1962, including that of the intestine. In some instances the primary focus of this tumor is unknown, but most of them are of metastatic nature originated in other parts of the body. Hematogenous metastasis of all malignant tumors to the gastric wall is considered as of relatively rare incidence. Of this rare gastric metastasis, its initial focus is said to be mostly found either in breast cancer in its terminal stage or in malignant melanoma of extragastric sources.

　Malignant melanoma of the stomach reported so far had been in most instances confirmed as such only after autopsy or surgical exploration, until in 1962 Reed reported the first case of gastric malignant melanoma ever confirmed prior to surgical operation by gastroscopic biopsy and cytologic diagnosis, its existence being suspected by preceding gastroscope examination.

　The case here presented is that of an extensive liver metastasis of malignant melanoma occurring eight years after it had been initially found in the chorioid of the left eye enucleated on account of glaucoma. Small metastatic foci in the gastric mucosa, detected by fibergastroscope, were later confirmed as of the same neoplastic etiology through histological diagnosis by means of biopsy under direct view. This case is believed to be the second case ever diagnosed by gastric biopsy. At autopsy it was found that besides gastric lesion each of such places as kidneys, lungs, spleen, heart and thoracic vertebrae was dotted with several small metastatic foci of hematogenous origin. Malignant melanoma of the stomach generally shows a picture of multiple polypi of various sizes; if it is accompanied by its specific discoloration, its endoscopic diagnosis is not diflicult. Of major significance is biopsy under direct vision for further corroboration of the diagnosis of this malignant neoplasm.