軟部に発生したchronic expanding hematomaの5例

Chronic Expanding Hematoma of Soft Tissue. Report of Five Cases

　軟部に発生したchronic expanding hematoma（以下CEH）の5例を報告する．経過は1カ月から30年，発生部位は下腿2例，上腕1例，殿部1例，大腿1例であり，外傷歴は3例に認められた．MRIでは内部はT1強調像で高信号，T2強調像で内部に散在する低信号域を認め，4例に低信号の被膜様構造が認められた．外傷歴があり，比較的長い経過で増大する腫瘍で，MRI上，上記のような所見がみられた場合，CEHも考慮するべきである．また，臨床上，軟部肉腫との鑑別が重要であり，確定診断には生検あるいは切除が必要と考えた．

　We report five unusual cases of chronic expanding hematoma (CEH) of soft tissue. Two of the five lesions, were in the calf, and one lesion each was in the upper arm, buttock, and thigh. The interval between the onset of disease and the timing consultation with our hospital varied from one month to 30 years, and in three cases there was a history of trauma at the site of the hematoma. All lesions were hyperintense on T1-weighted MR images and appeared as low intensity areas on T2-weighted images. In four cases a peripheral hypointense rim was noted on both the images. It is therefore advisable to suspect CEH in patients with a slowly expanding mass which is characterized with the signs described above on MR images, adding to the history of trauma. At the clinical level, differential diagnosis from soft tissue sarcoma is essential, and definite confirmation of the diagnosis should be obtained by biopsy or resection.