Isolated Prostatic Anterior Fat Pad Nodal Metastasis in High-Grade Anterior Prostate Cancer: A Case Report and Focused Narrative Review

Background/Objectives: Lymph node metastasis within the prostatic anterior fat pad (PAFP) is uncommon but may refine nodal staging when pelvic lymph node dissection and PSMA PET/CT are negative. Case Presentation: A 58-year-old man with PSA 59 ng/mL, negative digital rectal examination, and a PI-RADS 5 anterior lesion underwent transperineal MRI/US fusion biopsy, showing an acinar adenocarcinoma (Gleason score 5 + 5 = 10, ISUP grade group 5) confined to anterior cores. 18F-PSMA-1007 PET/CT showed intense intraprostatic uptake (SUVmax 55.2) without nodal or distant disease. Retropubic radical prostatectomy, bilateral extended pelvic lymph node dissection (ePLND), and separate PAFP submission were performed. Final pathology showed a 38 mm bilateral anterior tumor involving 35% of the prostate, focal anterior extraprostatic extension, negative margins, absent seminal vesicle and bladder neck invasion, perineural and lymphovascular invasion, and no cribriform or intraductal carcinoma. All 15 pelvic nodes were negative. One of two PAFP nodes contained a 3 mm PSA-positive metastasis without extranodal extension, resulting in pT3aN1 staging. Postoperative PSA persistence prompted radiotherapy plus androgen deprivation therapy; PSA was 0.01 ng/mL at 6 months. Conclusions: In very-high-risk anterior prostate cancer, separate PAFP evaluation may provide clinically relevant staging information when PSMA PET/CT and pelvic lymph nodes are negative. This case highlights the PAFP as a potential site of occult regional nodal disease.