Total penectomy as treatment option for solitary penile metastasis in hormone sensitive metastatic prostate cancer (mHSPC): Case report with surgical technique

Abstract

We present a case of a 66-year-old man with a three-year history of Gleason 10 prostate cancer (PCa), who presented with penile pain, erythema, and induration of the penile shaft. His cancer was treated with androgen deprivation therapy (ADT), radiotherapy, and apalutamide, resulting in PSA reduction; however, a solitary penile lesion persisted, necessitating radical penectomy. At 12 months post-surgery, PSA levels and magnetic resonance imaging findings remained stable, with no signs of metastasis. This case highlights the viability of radical penectomy for solitary penile metastasis in hormone-sensitive metastatic prostate cancer (mHSPC), with potential benefits for symptom control and survival.

Highlights

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Metastasis of prostate cancer to the penis is extremely rare.
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Systemic treatment is method of choice.
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Radical penectomy with perineostomy might be treatment option when penile metastasis persists.
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Recurrence free survival might exceed 12 months after radical penile surgery.

1 Introduction

Prostate cancer metastasizing to the external genitalia is exceedingly rare, with penile metastasis being the most common site. However, few cases are reported, typically managed with metastasis-directed therapy, which generally results in poor prognosis and death within 6–9 months. The survival benefits of radical surgery remain inconclusive.

Differential diagnoses for suspected penile metastasis include primary penile malignancies, metastatic spread from the pelvic or rectosigmoid regions, and benign conditions such as Peyronie’s disease. Diagnostic clarity is achieved through magnetic resonance imaging (MRI) and biopsy, the latter serving as the gold standard. Treatment decisions consider disease stage, patient condition, and quality of life. This report presents a case of metastatic hormone-sensitive prostate cancer (mHSPC) treated with radical penectomy and perineostomy, with no evidence of disease progression 18 months after initial detection of penile metastasis and 12 months postoperatively.

2 Case presentation

A 66-year-old man with a three-year history of oligometastatic prostate cancer (Gleason score 5 + 5, initial PSA 14 ng/mL) presented with penile pain and induration. His initial diagnosis included two metastatic lesions in the thoracic spine (T10 and T11), which were treated with radical radiotherapy and androgen deprivation therapy (ADT). Eight months prior to presentation, he reported penile pain and hardening of the penile shaft at a routine oncology follow-up. Over time, symptoms worsened, leading to difficulty retracting the foreskin and increased pain on palpation.

On physical examination, a solid, one-centimeter mass was observed on the glans penis and ventral surface of the midshaft, seemingly originating from the glans. Digital rectal examination showed an enlarged, firm, nodular prostate. The remainder of the physical exam was unremarkable, with no palpable lymphadenopathy, spinal tenderness, or neurological deficits. Given the mass’s suspicious appearance for squamous cell carcinoma (SCC), a penile biopsy was performed. Photographic documentation of the primary penile tumor was deemed unnecessary; therefore, no images of the original lesion are available . Pathology revealed multifocal Gleason 10 prostate cancer involving both the glans and corpora of the penis.

A follow-up MRI of the pelvis and prostate showed no evidence of tumor recurrence or lymphadenopathy. Concurrently, a bone scan identified a solitary osteoblastic lesion in the right tibia, and his PSA was recorded at 1.09 ng/mL. Given these findings suggestive of disease progression, apalutamide was added to his therapy. An excisional biopsy of the tibial lesion, conducted after orthopedic consultation, confirmed prostate cancer origin.

Further workup included prostate MRI, which demonstrated a Prostate Imaging Reporting & Data System (PI-RADS) 5 lesion, mildly enlarged pelvic lymph nodes, and a small sclerotic focus in the left iliac bone. No osseous metastatic disease was observed on the bone scan, and chest CT was normal. After discussion with hematology-oncology, the iliac lesion was considered non-metastatic. Treatment decisions were discussed with the patient, and the consensus was to initiate combined intensity-modulated radiation therapy and ADT with leuprolide acetate. He tolerated the treatment well, with a decrease in PSA over the following two years.

Upon ADT completion, PSA levels began to rise, necessitating resumption of hormonal therapy. At this time, he experienced a recurrence of penile pain and urinary symptoms. Repeat physical examination showed a firm, completely indurated penile shaft without exophytic tumors. MRI of the pelvis showed no signs of disease spread, with intact spongious body and urethra ( Fig. 1 ).