松果体部腫瘍4剖検例の病理学的検討

PATHOLOGICAL STUDY OF FOUR CASES WITH TUMOR IN THE REGION OF THE PINEAL BODY

はじめに

　松果体部腫瘍は臨床的に多彩な症状を呈し病理学的にもその組織発生・発育形式ないし転移・分類などに関して多くの問題を持つている。我々は松果体部腫瘍4例の剖検により，腫瘍の病理組織学的検索を行なつた。本論文において，その臨床経過，病理組織学的所見を述べ，文献的考察を加えて松果体部腫瘍の組織発生に関する一考察を呈示したい。

Tumors of the pineal region present a variety of clinical features and their pathogenesis and classi-fication are the subjects of considerable controversy. Four such ceses are reported here clinically and pathologically.

Case 1. A 25 year old male was admitted with chief complaints of double vision and vomiting. At autopsy, egg-sized tumor was found in the epiphysial region with diffuse infiltration to all the ventricular system and subarachnoid space. Microscopically, the tumor consists of a population of 2 cell types a large pale spheroidal or cuboidal cell and a smaller dense cell indistinguishable from a lymphocyte. Proliferation of connective tissue is prominent.Mitosis is frequent. Small cells are found especially along the connective tissue trabeculae and perivas-cular areas.

Case 2. A 19 year old male with diplopia and headache died 7 days after partial resection of tumor in the pineal region. At autopsy, tumor was found in the pineal region extending to the middle of the third ventricle. Microscopically, tumor consists of two cell types with relatively small number of small cells. Mitosis is moderate. Same type of tumor was found in the infundibular stalk.

Case 3. A 6 year old boy died two days after evacuation of cystic content from the tumor in the third ventricle. At autopsy, large cystic tumor was found in the epiphysial region and third ventricle. Microscopic examination revealed mature teratoma with portions of tumor with two cell types as seen in cases 1 and 2.

Case 4. A 19 year old male showed polydipsia and polyuria. At autopsy, tumor occupied the anterior two third of the third ventricle. Micro-scopically, immature teratoma with portions of embryonal carcinoma and choriocarcinoma was noted. Tumor with two cell types as seen in the above cases was also found in the pineal region, infundibular stalk and posterior lobe of pituitary gland.

Tumor consisting of two cell types shows close resemblance to seminoma as pointed out by D. S. Russel and N. B. Friedman. Our observation on 4 cases reveals two cases with pure seminoma, one with mature teratoma and seminoma and one with immatureteratoma, embryonal carcinoma, choriocar-cinoma and seminoma Pathological study of tumors showing seminomas in the pineal region seems to support the view that they are of germ cell origin.