癌腫および平滑筋腫と合併した胃のGranular Cell Myoblastoma

Granular-cell Myoblastoma of the Stomach Associated with its Carcinoma and Leiomyoma

　いわゆるgranular cell myoblastomaは腫瘍か否か，またその発生についても諸説があり，興味ある病変である．1926年Abrikossoff¹⁾が13例を報告して以来，多数の文献があるが，その発生部位としては舌が最も多く，(Strong²⁾；39/110病変，小林³⁾；5/46病変)その他皮膚，口唇，四肢の筋肉などに多く，稀に脳下垂体茎部⁴⁾，乳腺⁵⁾，膀胱⁶⁾⁷⁾，迷走神経⁸⁾にもみられる．舌以外の消化管に発生するものは比較的稀であるが，食道^9)～12)，胃，十二指腸¹³⁾，虫垂¹⁴⁾，結腸¹⁵⁾，胆道^16)～18)など約二十数例の報告がある．このうち胃に発生したものは8例にすぎず，著者らも胃癌で切除された胃に，平滑筋腫とともに合併したgranular cell myoblastomaを経験し，電子顕微鏡的にも観察し得たので報告する．

　The so-called granular-cell myoblastoma is an intriguing lesion not only because opinion is divided whether it is a tumor or not but also because it is disputed where does it originate from. Reportedly its predilection sites include the tongue, skin, lips and muscles of the extremities. In the digestive tract it is said to originate additionally in the esophagus, stomach, duodenum, appendix, rectum and gallbladder. The present paper deals with a case of granular-cell myoblastoma recently encountered in association with cancer and Leiomyoma of the stomach.

　The patient, a 58-year-old man, was performed gastrectomy under a provisional diagnosis of cancer of the pylorus two months after the onset of symptoms. Actually, as there was Schnitzler's metastasis with a judgment of Stage IV, only the original lesions were excised.

　The resected specimen showed that, in addition to a Borrmann II Type cancer extending all along the entire wall of the pyloric wall, a leiomyoma the size of a soy bean in the subserosa of the anterior wall of the body and a submucosal tumor half the size of a grain of rice were seen, which proved to be granular-cell myoblastoma. The tumor cells contained within the cytoplasm fine granules slightly positive for PAS stain, distributed in parts in spiral or wave-like fashion, resembling in places Schwann cells of the peripheral nerves, and in the margins arranged in places as in histiocyte. Electron microscopy showed fine granules of characteristically high electron density in the cytoplasm, but neither myogenic fiber nor axon was demonstrated. The patient succombed to recurrence of cancer one year and two months after the surgical intervention.

　According to eight cases reported in the literature of granular-cell myoblastoma of the stomach, there was no predilection for sexes, occurring mostly in the body. Either submucosal layer or the serosa was affected by it, and polyp-like hyperplasia of the gastric mucosa was seen over the growth. Symptoms similar to those of ulcer were said to appear.