Papillary cystadenocarcinoma of the prostate: a case report

Abstract

A 91-year-old man presented with nocturnal frequency and urge incontinence of a few days duration due to involvement of prostate cancer (PCa) accompanied by a large cyst in the left lobe of the prostate gland and urinary bladder wall. Channeling transurethral resection of prostate was performed to relieve the main symptoms and the resected material was histologically diagnosed as papillary cystadenocarcinoma arising from the epithelium of microscopic retention cysts. Following shrinkage of the large cyst, the patient is doing well on a combination regimen of a luteinizing hormone-releasing hormone analogue and bicaltamide. Papillary cystadenocarcinoma of the prostate was originally defined as papillary PCa arising from, not accompanied by, prostatic cysts. Cysts associated with PCa are subdivided into primary (or true) and secondary (or pseudo) cysts. Cancer cells in primary cysts originate from the epithelial lining. Papillary growth type cysts belong to this group and are regarded as papillary cystadenocarcinoma. The secondary (or pseudo) cysts, which have no epithelial lining and consist of hemorrhagic and/or necrotic contents are associated with invasive PCa. In the present case, the microscopic retention cysts revealed by histologic examination were of the primary type. This case of papillary cystadenocarcinoma, arising from a primary cyst, is the 13th such report from among previously reported cases in Japan.

91歳, 男性。主訴は数日前から続く夜間頻尿と尿失禁。PSA 325ng/mlと高値で, 前立腺の左葉が石様硬であった。DIPとUCGでは膀胱と尿道は右側へ偏位し, 左腎は無機能であった。MRIでは前立腺から膀胱の左側へまたがる径5cmの嚢胞を伴った腫瘍を認めた。前立腺生検では高分化型前立腺癌を認めた。排尿困難改善のためchanneling TURを施行したところ, 病理診断は貯留嚢胞上皮から発生した乳頭状嚢胞腺癌(Gleason score 6, C2)であった。内分泌治療は間欠的に施行し, 治療開始後41ヵ月現在, 嚢胞壁は縮小し, 再燃・転移なく通院加療中である。嚢胞を伴う前立腺癌は比較的稀で, 嚢胞壁が癌化する原発性嚢胞と癌が中心壊死・出血を起こし形成される二次性嚢胞に分類されている。自験例では原発性嚢胞と考えられる貯留嚢胞上皮が癌化した非常に稀な前立腺乳頭状嚢胞腺癌であり, 本邦13例目であった。(著者抄録)