脳下垂体機能不全にて発症し，画像診断上Germ Cell Tumorを疑わせた頭蓋内原発T細胞型悪性リンパ腫の1例

A Case of Primary Intracranial T Cell Type Malignant Lymphoma, Radiologically Resembling Germ Cell Tumor and Presenting Hypopituitarism

I．はじめに

　近年頭蓋内原発悪性リンパ腫の報告は，数多くなされているが，そのなかでも，T細胞型悪性リンパ腫の報告は現在われわれが知り得た限りでは，8例のみである^{4,712,13,15,21,25）}．また，本例のように，脳下垂体機能不全で発症した例は，過去に3例の報告があるのみである^9,16，17）．また，頭蓋内原発悪性リンパ腫は，一般に正中構造物に発生するとされているが，本例のように，松果体部，鞍上部，延髄背側部にあたかもgerm cell tumorの播種の如き像を呈した例は，われわれの知り得た限りでは，過去に報告はない．われわれは，そのような稀有と思われる1例を経験したのでここに報告する．

A 21-year-old man was hospitalized with complaints of headache, nausea, polyuria, reduced body hair and re-duced libido. Plain CT scan and MRI revealed multiple tumors in the pineal and suprasellar regions, and in the dorsal aspect of the medulla oblongata. Endocrinological examination showed hypopituitarism due to hypothala-mic dysfunction. Replacement therapy with hydrocorti-sone was started preoperatively. Suprasellar tumor was explored. Postoperative CT scan and MRI showed marked diminishment of not only suprasellar tumor, but also tumors in the two other regions. These tumors were supposed to be sensitive to corticosteroid hormone. His-topathological diagnosis was T cell type malignant lym-phoma. The patient was followed up for 10 months post-operatively with no recurrence on CT scan.

Primary intracranial malignant lymphoma is not a rare disease today. However, primary intracranial T cell type lymphoma is extremely rare. Hypopituitarism due to suprasellar malignant lymphoma is also rare, and only 3 such cases have been reported previously. In our case, the tumor was located in the pineal and suprasellar re-gions, and the dorsal aspect of the medulla oblongata. Such disseminated malignant lymphoma as ours shows radiological resemblance to germ cell tumor. No such dis-seminated malignant lymphoma has been reported pre-viously. We think that, in its radiological and clinical fea-tures, our case is very suggestive of primary in-tracranial malignant lymphoma.