Cutaneous metastasis from prostate cancer: A case report with literature review

A 68-year-old man with a 3-month history of low back pain presented to urgent care, where X-rays revealed rib abnormalities. Further workup was significant for an elevated prostate-specific antigen (PSA) to 285. Technetium-99m-MDP bone scan and computed tomography showed extensive sclerotic osseous metastatic disease within the axial and appendicular skeleton and adenopathy in the retroperitoneum, pelvis, and superior mediastinum. Biopsy of a pelvic lymph node confirmed the diagnosis of prostate adenocarcinoma. The patient was treated with androgen deprivation therapy with luteinizing hormone-releasing hormone agonist along with targeted endocrine therapies. Despite initial PSA and radiographic response, 2 years after diagnosis, PSA started to rise. He developed a raised, erythematous plaque on his right upper chest. Biopsy revealed a poorly differentiated basaloid tumor consistent with metastatic prostate adenocarcinoma. He was started on docetaxel chemotherapy with a marked improvement of his skin lesion and decline in PSA. Unfortunately, the patient experienced disease progression with worsening bone and lymph node metastasis and died eight months after initial skin findings. It is crucial to suspect cutaneous metastasis in individuals with persistently elevated PSA despite treatment, especially if they develop nodular lesions.