[A Case of Giant Multilocular Prostatic Cystadenoma Resected by Laparoscopic Pelvic Cystectomy : A Case Report].

A 60-year-old man visited our hospital to treat a large cystic mass in the pelvis which had been found by abdominal ultrasonography in December 201X. Computed tomography (CT) and magnetic resonance imaging (MRI) showed a multilocular cyst with a maximum diameter of about 10 cm. CT-guided drainage and sclerotherapy with minocycline reduced the size of tumor by 40%, but symptoms such as difficulty of defecation and urinary frequency appeared a year and a half later due to re-enlargement of the cysts. Laparoscopic resection of the multilocular cysts was performed, and all cysts were removed almost completely using transrectal ultrasonography. The multilocular cyst was positive for NKX3.1 by immunohistochemical staining, and was diagnosed as a giant multilocular prostatic cystadenoma. After surgery, the symptoms such as difficulty of defecation and urinary frequency were relieved promptly. One year after the surgery, the patient was free from recurrence of the disease.

Pelvic MRI, FDG-PET/CT, and Somatostatin Receptor Scintigraphy Findings of Treatment-Related Neuroendocrine-Differentiated Prostate Cancer.

Treatment-related neuroendocrine-differentiated prostate cancer (NEPC) is a rare tumor entity that transdifferentiates from adenocarcinoma as an adaptive response to androgen receptor pathway inhibition. We report a 79-year-old male with treatment-related NEPC, presenting as rectal bleeding after hormonal therapy. MRI showed a 51 × 52 × 65 mm tumor occupying almost the whole prostate gland and invading the seminal vesicle and rectum as moderately heterogeneous hypointensity on T2-weighted image, restricted diffusion on apparent diffusion coefficient map and diffusion-weighted imaging, and heterogeneous enhancement on Gd-enhanced T1-weighted image. FDG-PET/CT showed strong FDG uptake of the prostate tumor, and somatostatin receptor scintigraphy (SRS) showed mild uptake of the prostate tumor. The surgically resected specimen revealed NEPC. If prostate cancer worsens despite conventional therapy, treatment-related NEPC should be considered, and the benefit of imaging examinations including prostate MRI, FDG-PET/CT, and SRS is in localizing lesions with neuroendocrine differentiation.