Metastatic prostatic adenocarcinoma mimicking inflammatory breast carcinoma: a case report

Prostate adenocarcinoma can manifest as a fairly indolent tumor or as a very aggressive cancer with significant invasive and metastatic potential. Common metastatic sites include bone, liver, lymph nodes, and adrenal glands. Dermatologic manifestations are rare. We present a case of a man who presented with breast skin changes that mimicked inflammatory breast carcinoma with specialized testing ultimately giving a diagnosis of metastatic prostatic adenocarcinoma. A 78-year-old man presented with left breast redness and swelling. Examination revealed an erythematous rash with subcutaneous edema over the left hemithoracic area. A breast ultrasound showed no focal mass, and a breast core biopsy had no evidence of tumor. A skin biopsy showed metastatic carcinoma in dermal lymphatics, and the tumor was found to have no estrogen or progesterone receptors or HER2 expression. Computed tomography scans, positron emission tomography, and a nuclear bone scan revealed widespread skeletal metastases. The patient received a 3-month course of capecitabine and cyclophosphamide with no improvement in his skin lesions. Subsequent immunohistochemical staining on the tumor specimen was positive for prostate-specific antigen (PSA) and alpha-methyl-CoA-racemase, confirming a diagnosis of metastatic prostatic adenocarcinoma. He received leuprolide and bicalutamide and demonstrated significant improvement with near-complete resolution of his skin lesions and a decrease in his PSA level. Prostatic adenocarcinoma presenting initially as a breast malignancy is a rarely recognizable clinical event. Undoubtedly, increased awareness and recognition of the rare entity described herein will allow for the prompt initiation of specific therapies, which might be of benefit to many patients.