A case of ectopic prostatic tissue presenting as a cystic pelvic mass

A 74-year-old man initially presenting with fall had an incidental finding on CT of a heterogeneous, partly cystic lesion in the pelvis that was moderately glucose avid on FDG-PET. The pelvic mass and adherent right seminal vesicle were excised. On microscopy, the pelvic mass was comprised of benign prostatic acini supported by fibromuscular stroma adherent to a normal seminal vesicle. The prostatic tissue stained positive for NKX3.1 and PSMA. PIN4 showed negative staining for AMACR with retention of normal staining for basal markers. Ectopic prostate tissue (EPT) is an uncommon entity found at various sites within and outside the male genitourinary system. It is an important differential diagnosis to consider whenever prostatic glands are seen outside their normal distribution.1 Rarely EPT can undergo hyperplastic or malignant changes. Awareness of this entity is significant to avoid either misdiagnosis or upstaging those with primary prostate cancer. Reference 1.. Gardner JM, Khurana H, Leach FS, et al. Adenocarcinoma in ectopic prostatic tissue at dome of bladder: a case report of a patient with urothelial carcinoma of the bladder and adenocarcinoma of the prostate. Arch Pathol Lab Med 2010; 134: 1271–1275.