The Prostate Problem You Can’t Put Your Finger on the Normal Way: A Case of Perineal Prostate Cancer Post Transperineal Prostate Biopsy

Transperineal biopsy needle-tract tumour seeding is a rare complication, with sparse published literature [1]. We describe the management of metastatic prostate cancer secondary to transperineal biopsy needle-tract seeding.

An 80-year-old male presented with an otherwise asymptomatic, hard perineal mass that had progressively enlarged over a few months. The patient’s urological history included prostate adenocarcinoma of the right prostatic-apex, prostatic urethra, and lymph nodes (ISUP-Grade 4 [4 + 4 = 8], PIRADs-5, PSA-level 2.7 µg/L), diagnosed via transperineal biopsy and TURP 3 years prior. His prostate cancer was definitively managed with TURP, ADT, and radiotherapy with a post-treatment PSA-level of 0.05 µg/L.

On pelvic examination, a perineal 2 cm fixed lump was palpable. Pelvic-MRI demonstrated a 20 mm irregular mass in the perineal fat immediately below the penile base (Figure 1A). Repeat PSA-level was 6.0 µg/L. Subsequent PSMA PET-scan revealed a PSMA-avid lesion in the perineal midline, consistent with prostatic neoplasm metastasis without other metastatic disease (Figure 1B). Cystoscopy showed no obvious urinary-tract cancer recurrence.

The patient’s case was discussed in a multi-disciplinary team meeting and excision was recommended. The patient then underwent a wide-local excision, requiring partial resection of bulbar-spongiosum (Figure 1C). Histopathology revealed a complete excision of his prostate adenocarcinoma metastasis, with post-excision PSA-levels of 0.12 µg/L. No adjuvant therapies were given.

Needle-tract seeding following transperineal prostate biopsy is rare and should not preclude patients from undergoing biopsies. This case highlights the need for patient follow-up after cancer treatment and exemplifies the practicality of PSMA PET-scans if there is evidence of rising PSA-levels after definitive prostate cancer treatment.