剖検例からみた脾腫

Splenomegaly－From the pathological and anatomical point of view.

　脾は種々の疾患に際して腫大し，臨床的には左季肋部の切痕を有する腫瘤として触知され，また季肋下に及ばぬものでも脾濁音界の拡大として認識される，さらには腹腔鏡による直視下の観察，血管撮影および放射性同位元素（⁵⁹Fe，⁵¹Crなど）を用いての脾部体表面計測などの方法により脾腫の病態を臨床的に，的確に把握することが可能となってきた．

　一言に“脾腫”といっても脾腫を来す基礎疾患は多様であり，かつおのおのの疾患に際しての脾の病理形態像は種々である．脾腫を来す基礎疾患の詳細な分類や鑑別は成書にゆずるが，多くは白血病や悪性リンパ腫のごとき種々の血液疾患，Banti症候群や門脈圧亢進を伴う肝疾患，マラリア，カラ・アザールのごとき慢性感染症，稀に種々の蓄積病や脾原発の悪性腫瘍などである．これらの脾腫に際して認められる臨床症状は，その基礎疾患によるものの他に，脾機能亢進症状としての汎血球減少，さらには巨大な脾腫による消化管の圧排，狭窄による消化管通過障害や腫瘍の消化管壁への浸潤およびその潰瘍形成による消化管内大量出血，梗塞による腹痛などの腹部症状を呈することがある．

　Enlargement of the spleen is considerably common in various diseases, such as hematological disorders includingleukemia and malignant lymphoma, Banti's syndrome and liver cirrhosis, various kinds of infection, storage diseases and rarely splenic neoplasms, although histopathological appearances differ from case to case. Although clinical signs and symptoms depend upon the fundamental diseases causing splenomegaly, some show signs of hypersplenism, obstruction of the G-Ⅰ tract due to compression by the enlarged spleen, and infiltration of the splenic tumor into the wall of the G-I tract resulting in massive hemorrhage.

　In this report 5 cases with splenomegaly, including two of primary malignant neoplasma of the spleen and one of splenic cyst, are mentioned.

　Malignant neoplasms of the spleen are very rare. There have been three primary malignant neoplasms of the spleen in 2600 autopsy cases at Toranomon Hospital for the past fifteen years. According to Ahmann, who reported 49 cases of primary malignant lymphoma of the spleen, its incidence is less than 1% of total malignant lymphomas. Of the 49 patients, preoperative diagnoses were malignant lymphoma in 23, and indeterminate splenomegaly, hypersplenism, and Banti's syndrome in the others. Since Skarin emphasised the good prognosis in 11 cases of primary lymphosarcoma of the spleen, indication for splenectomy should be considered whenever occasion arises.