前立腺炎症性偽腫瘍の1例

Abstract

42歳男.約3年前に血精液症及び慢性前立腺炎に対して3ヵ月間の抗生剤内服を行い, 症状の消失を認めたが, 直腸診でくるみ大で圧痛を伴う男性硬の前立腺を指摘された.排尿困難が出現し, 膀胱鏡検査で膀胱結石及び前立腺部尿道を占拠した非乳頭状腫瘍を認め入院となった.内視鏡及び画像検査と経直腸的前立腺針生検により, 前立腺の良性腫瘍病変による排尿困難と, 膀胱結石及び射精管閉塞による精嚢腺嚢胞の合併と診断された.膀胱砕石術及びTUR-Pを施行し, 病理組織学的診断は前立腺炎症性偽腫瘍であった.術直後より排尿困難は改善し, 術後5ヵ月のMRIで前立腺炎症性偽腫瘍の残存と精嚢腺嚢胞を疑う再発が見られたが, 良好な排尿状態を維持している

We report a rare case of inflammatory pseudotumor of the prostate. A 42-year-old man with a history of hematospermia and chronic prostatitis presented with difficulty in voiding. Cystoscopy demonstrated a large non-papillary tumor occupying the prostatic urethra along with two bladder stones. Magnetic resonance imaging (MRI) demonstrated a 7-cm prostatic mass protruding toward the bladder and the rectum. Transrectal biopsy of the prostate demonstrated a fibrous lesion containing inflammatory cells without evidence of malignancy. We performed transurethral resection of the prostatic lesion to release the bladder outlet obstruction, followed by cystolithotripsy. Histopathological examination of the surgical specimen demonstrated a benign fibromuscular lesion with spindle cell proliferation, leading to a diagnosis of inflammatory pseudotumor. Postoperatively, the patient voided normally without any signs of recurrence on follow-up at five months. Inflammatory pseudotumor is an unusual benign lesion of unknown etiology. Only 10 previous cases of the disease involving the prostate have been reported in English and Japanese literature. Prostatic involvement of inflammatory pseudotumor may show a presentation similar to malignant prostatic sarcoma. Thus, accurate identification of this benign process is important in order to avoid unnecessary radical surgery.