Cutaneous metastasis of prostate cancer: a case report and review of the literature with bioinformatics analysis of multiple healthcare delivery networks.

Distant cutaneous metastases of prostate carcinomas are extremely rare, despite its high incidence and prevalence. Most cases are either a result of local extension, such as into seminal vesicles or distant metastases to bone. Few cases of true cutaneous metastatic prostate carcinoma exist in the literature. Clinically, cutaneous prostate carcinoma has been reported to mimic many other conditions, such as cellulitis, sebaceous cysts, zosteriform lesions, telangectasias and more, resulting in poor recognition. We report a case of distant cutaneous metastasis of prostate carcinoma and recent review of the literature with an analysis of de-identified patient records from multiple healthcare delivery networks. A diagnosis of metastatic prostate carcinoma may have been easily overlooked given the location and nature of the rash. Reviewing case reports and using aggregated electronic health records (EHRs), we find that fewer than 0.1% of all prostate carcinomas result in cutaneous metastases, compared with much higher rates in other types of cancers. Coupled with the low frequency of metastases to skin, careful consideration must be taken when evaluating a rash in a patient with a prior history of cancer. A complete clinical history and strong suspicion would be required to make a diagnosis of cutaneous metastases of the prostate.