A Scrotal Rash Lasting Months in a Man With Genital Edema

Winston W. Tan, MD; Matthew S. Soberano, DO; A. Toledo, DO; Matthew Clarence Tan


June 23, 2022

In a study of 2369 cases of cutaneous metastases arising from 81,618 primary solid visceral malignancies, skin metastasis was reported in 2.9%.[9] Primary urologic malignancies of the testes, prostate, bladder, and kidney were found in 116 (1.3%) of 10,417 cases. The incidence of cutaneous metastases from the testes, prostate, bladder, and kidney was 0.4%, 0.36%, 0.84%, and 3.4%, respectively. Overall, 436 cases of cutaneous metastases from urologic organs were catalogued. Infiltrated plaque or nodules were the most common presentations. Typically, the clinical features mimicked common skin disorders. From the date of presentation, disease-specific survival had a median of less than 6 months.

Cutaneous metastasis due to prostate cancer is extremely rare. In a review of pathologic specimens at UCLA Hospital, 2 of 136,017 surgical and postmortem specimens had this condition.[4] In another review, cutaneous metastases accounted for 0.3% of prostate metastases.[5] The lesions are often multiple solid nodules that rarely ulcerate. Occasionally, they present as red macules or papules, few in number, and are usually localized in the suprapubic and anterior aspect of the thigh. Cutaneous metastasis often signifies advanced disease and portends poor prognosis (most patients die within 6 months). Immunohistochemical study with PSA confirms the prostatic origin of metastases.

This patient presented with skin metastases 14 years after the initial diagnosis of prostate cancer. Recognizing cutaneous metastasis as a differential diagnosis of a skin lesion in a patient with a history of prostate cancer is important for both diagnostic and prognostic purposes.

When leuprolide stops working, several new drugs have been approved for patients with castration-resistant metastatic prostate cancer, including docetaxel, sipuleucel-T, abiraterone acetate with prednisone, and enzalutamide. All these have been approved by the US Food and Drug Administration (FDA) because they improve survival by 4-6 months, on average.[10]

With the exception of skin cancer, prostatic adenocarcinoma represents the most common cancer among men in the United States and is the second most common cause of cancer mortality. Mortality is often associated with metastatic disease; in the case of prostatic adenocarcinoma, this typically involves bones and rarely affects the skin. Although clinical history and examination, laboratory tests, and routine pathology can suggest the prostate as a source of metastatic disease, immunohistochemistry—specifically PSA—is often used to help establish the diagnosis.


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