Lethal Porocarcinoma in an Immunosuppressed Host: A Case Report in a Kidney Transplant Recipient

Eccrine porocarcinoma (EPC) is an extremely rare skin adnexa malignancy, occurring worldwide at an estimated 0.005% to 0.01% rate. It has a variable clinical and histological presentation with aggressive behavior in immunosuppressed patients. This case report showcases the challenges of diagnosis and treatment. As far as we know, this is the first reported case of porocarcinoma in Croatia.

We present a 63-year-old patient with a kidney transplant due to glomerulonephritis of unknown origin. The patient presented with a lesion in the sacral region measuring 10 × 8 cm. Atheroma was initially suspected due to morphology. Incision and drainage were performed on the lesion. Continuation of bleeding, pain, and discomfort warranted a punch biopsy. It revealed fibrous tissue and nests of atypia and mitosis. A wide local excision was carried out. Histopathology showed an invasive malignancy, EPC. Ki-67 was positive in over 40% and even 70% in certain hotspots. The patient complained of newly developed headaches. Magnetic resonance verified 2 cerebellar metastases and one metastasis located in the temporal lobe. A later PET/CT scan confirmed further dissemination in the lungs, liver, ascending colon, and muscle of the right thigh laterally. Palliative gamma knife brain surgery was used, as well as palliative chemotherapy. The patient passed away after 5 months of diagnosis.

Data on porocarcinoma in kidney transplant patients is scarce; this case hopes to provide some useful insight.