Adjuvant radiotherapy in the management of porocarcinoma with lymphatic micrometastasis

Background. Porocarcinoma is a rare skin tumor originating from dermal sweat glands. Surgical procedures are the first choice of treatment, but the role of adjuvant therapies, such as chemotherapy and radiotherapy (RT), is not clear. In this case report and review of the literature, we aimed to present a patient who underwent adjuvant RT for the diagnosis of porocarcinoma with lymphatic micrometastasis and a review of the current literature. Case summary. A 61-year-old male was admitted to the dermatology department for a nodular lesion on the left knee skin. An excisional biopsy was performed, and the pathology result was reported as porocarcinoma. The closest surgical margin of the tumor was 0.2 cm. In the inguinal sentinel lymph node sampling, two of the three removed lymph nodes had micrometastases. Then, adjuvant RT was applied to the left inguinofemoral lymphatics and primary tumor bed. No recurrence was observed in the patient with a follow-up period of 24 months. No acute or late toxicity was observed including lymphedema, subcutaneous fibrosis, or stiffness of the knee joint. Conclusions. Although adjuvant RT is not a routinely recommended treatment, it can be applied to increase local and regional control in patients with high-risk factors for recurrence or with lymph node metastases. There is a great need for clinical studies clarifying the role of RT, but for now, all patients should undergo multidisciplinary evaluation when a decision on adjuvant therapies is made