スキルス胃癌と鑑別を要する非腫瘍性疾患―里吉症候群の胃病変

Gastric Lesions of the Satoyoshi Syndrome

要旨　里吉症候群は進行性筋痙攣（こむら返り），全身脱毛，下痢を3主徴とする疾患であり，まれにGCPに起因した消化管病変を来す．このうち，胃壁にびまん性の線維性肥厚を来した例においては，スキルス胃癌類似の広範な壁の伸展不良所見とともに，leather bottle様の変形を呈する例が存在する．典型的スキルス胃癌との鑑別所見は，（1）壁辺縁の不整硬化に乏しく，わずかに伸展性が保たれている点，（2）スキルス胃癌特有のIIc面を認めない点に加え，本疾患の特異的な形態所見である，（3）粘膜上皮の脱落あるいは著明な萎縮による島状の胃底腺粘膜の残存から成る多発性顆粒状隆起の存在，（4）粘膜固有層の腺の嚢胞状拡張，粘膜下層の深在性嚢胞に起因する多発性粘膜下隆起の存在である．病理組織学的所見ではGCPの所見に加え，粘膜固有層浅層に帯状あるいは層状の線維性増生，粘膜固有層深層に浮腫を認め，生検診断の一助となる可能性がある．このような病態を知ったうえで，特徴的な3主徴，先行する十二指腸，小腸病変の存在などから本疾患を疑い，上記所見をとらえることができれば，スキルス胃癌との鑑別は容易である．

　Satoyoshi syndrome is characterized by 3 principal manifestations, namely, progressive muscle spasms（muscle cramps）, generalized alopecia and diarrhea, and, rarely, gastrointestinal lesions attributable to GCP（gastroenterocolitis cystica polyposa）. In some of these cases diffuse fibrous thickening develops in the gastric wall, and some of the patients exhibit evidence of widespread poor distensibility of the gastric wall and leather-bottle-like deformation resembling scirrhous gastric carcinoma. Findings that enable differential diagnosis from typical scirrhous gastric carcinoma are :（1）little irregular stiffening of the wall margin, and distensibility maintained to a very small extent,（2）the typical morphological findings of Satoyoshi syndrome in addition to the absence of the unique IIc surface of scirrhous carcinoma,（3）the presence of multiple granular protrusions composed of island-like fundus gland remnants due to loss of the mucosal epithelium or severe atrophy, and（4）the presence of cystic dilatation of the glands in the lamina propria mucosae and multiple submucosal protrusions caused by deep cysts in the submucosa. In addition to the findings of GCP, the histopathological findings consist of band-like or laminar fibrous hyperplasia in the superficial layer of the lamina propria mucosae and edema in the deep layer, and these findings may be helpful in making a diagnosis by biopsy. After learning about this pathology, if Satoyoshi syndrome is suspected based on the presence of the characteristic 3 principal manifestations and the preceding duodenal and small bowel lesions, and the above-described findings are detected, it is easy to differentiate Satoyoshi syndrome from scirrhous carcinoma of the stomach.