Umbilicus Porocarcinoma: An Uncommon Neoplasm at a Unique Site.

Eccrine porocarcinoma is a rare and aggressive cutaneous neoplasm that mainly affects the elderly patients. It occurs more often in the head and neck, followed by lower limbs. The abdomen, especially the umbilicus, is a very rare presenting location. Diagnosis can be challenging and is usually made based on a combination of clinical, dermoscopical and histopathological findings. The main treatment approach is wide surgical resection, with negative margins. Despite resection, development of nodal or distant metastasis occurs in a few cases. Adjuvant treatment modalities consist of radiotherapy and chemotherapy, but the results are inconsistent. Immunotherapy is a novel option to treat these cases, but more studies are needed. Here we present the case of a 73-year-old woman who presented with an enlarging umbilical mass, initially thought to be a metastatic lesion, but the imaging and endoscopic exams showed no other primary tumor. So a biopsy was performed, which revealed a localized eccrine porocarcinoma. After a multidisciplinary decision, the tumor was resected with free margins and no additional treatment was needed. The patient remains in follow-up, with no signs of local recurrence nor nodal or distant metastasis.