隆起型食道癌の病理診断―扁平上皮癌以外の隆起型食道腫瘍の病理学的特徴

Histopathological Diagnosis of Polypoid Type Esophageal Carcinoma: Clinicopathological Features of Basaloid-squamous Carcinoma, Carcinosarcoma, and Malignant Melanoma

要旨　特殊型組織型食道癌のうち，類基底細胞（扁平上皮）癌（53.8％），癌肉腫（88.9％），悪性黒色腫（100％）はともに過去の報告と同様に隆起型を示していた．組織学的発育様式は，癌肉腫と悪性黒色腫では異なるが，それぞれでほぼ均一な発育様式であった．すなわち，癌肉腫では腫瘍のボリュームにより上方へ突出し，表面はほぼ全体が潰瘍化していた．悪性黒色腫ではそれとは対照的に，部分的に潰瘍を伴うが基本的には非腫瘍性上皮に覆われ，粘膜下腫瘍様を呈していた．一方，類基底細胞（扁平上皮）は，前2者と比較すると組織構築は多彩であり，その多くは上皮内扁平上皮癌から発生して上皮下浸潤性発育を基本としているが，進展とともに潰瘍化し，悪性度を増していくと考えられる．生検による確定診断の際には，これらの組織構築を考慮して組織を採取する必要がある．

　Among special histological types of esophageal carcinoma, a polypoid type was frequently seen in BSC（basaloid-squamous carcinoma）（53.8％）, carcinosarcoma（88.9％）, and malignant melanoma（100％）, as previously reported.

　The histological architecture was different between carcinosarcoma and malignant melanoma, but it was nearly uniform in each one. That is, carcinosarcoma protruded upward by volume of the tumor, and its surface is almost ulcerated. In contrast, malignant melanoma was basically covered by squamous epithelium and exhibited submucosal tumor. On the other hand, the histological architecture of BSC was variable compared with the former two. It is considered to arise from squamous cell carcinoma in situ, and grow beneath squamous epithelium basically, and progress to aggressive tumor with ulceration

　For a definitive diagnosis by biopsy, tissue must be taken from an appropriate site considering the histological architecture.