顔面外傷後の血腫として初期治療された副鼻腔びまん性大細胞型B細胞リンパ腫の1例

A Case of Diffuse, Paranasal, Large B-Cell Lymphoma Mimicking a Traumatic Facial Hematoma

はじめに

　今回われわれは，鈍的外傷部の腫脹により当初血腫と判断されたが増大し，副鼻腔びまん性大細胞型B細胞リンパ腫（sinonasal diffuse large B-cell lymphoma：以下，SN-DLBCL）の診断に至った1例を経験した。外傷部であっても腫脹が長びく場合の鑑別には腫瘍性病変を考慮し，造影MRI検査と組織生検を行うことが重要である。文献的考察を加えて報告する。

　Malignant tumors of the paranasal sinuses are rare. We report the case details of a patient with a diffuse large B-cell lymphoma that originated in the paranasal sinus and mimicked an orbital fracture-associated hematoma. A 48-year-old man with a history of blunt trauma to his left cheek visited several hospitals with complaints of cheek swelling and double vision. Initially diagnosed with a retrobulbar hematoma and orbital-floor fracture, he underwent a surgical hematoma removal at another hospital. The patient was referred to our hospital for further evaluation and treatment.However, the swelling worsened during the three weeks after the patient came to our hospital, where contrast-enhanced computed tomography revealed left submandibular lymphadenopathy. Based on the histopathology of the left cheek lesion and a lymph-node biopsy specimen, we diagnosed a diffuse large B-cell lymphoma. Bone marrow aspiration and lumbar puncture at our hospitalʼs hematology department showed no central nervous system invasion. Accordingly, a Stage IV non-germinal center B-cell subtype DLBCL (Ann Arbor Classification) was diagnosed. The tumor disappeared quickly after chemotherapy. At the 1-year follow-up, complete lymphoma remission and no recurrence were confirmed. Clinicians should consider the differential diagnosis of malignant lymphoma for patients with multiple soft-tissue shadows on computed tomography performed for a trauma workup.