右上腕に発生した異型顆粒細胞腫の1例

An Atypical Granular Cell Tumor in the Right Upper Arm

はじめに

　顆粒細胞腫（granular cell tumor：以下，GCT）は，1926年にAbrikossoff 1）により初めて報告された比較的まれな神経原性の腫瘍である。頭頸部，乳腺，四肢近位，消化器および呼吸器領域の皮膚皮下や粘膜下に発生し，悪性の頻度は低く，その発生頻度は全顆粒細胞腫のうちの2 ％程度とされている 2）。今回われわれは，部分生検時には良性の顆粒細胞腫と診断されたが，全切除後に異型顆粒細胞腫（atypical granular cell tumor：以下，AGCT）と診断された症例を経験したので，文献的考察を加え報告する。

　First reported by Abrikossoff in 1926, granular cell tumors are neurogenic tumors that occur in the head and neck, breast, proximal extremities, and digestive and respiratory systems. They are usually benign; only ~2% are malignant. We present a patientʼs case and a literature review. A 71-year-old woman presented with a mass on her upper right arm. Magnetic resonance imaging (MRI) revealed a 20-mm-wide mass; it had been diagnosed as a benign granular cell tumor based on a partial biopsy. When the complete excision was performed, an atypical granular cell tumor was discovered. Although granular cell tumors typically have low malignant potential, caution is necessary due to reported cases of malignancy. Proper MRI and pathological diagnoses are required, and complete excision is desirable.