Sentinel Lymph Node Biopsy in Porocarcinoma: A Case Reports

INTRODUCTION Eccrine porocarcinoma (EPC), first described by Pinkus and Mehregan in 1963, is a rare form of skin cancer. Its presentations very often mimics a cutaneous lesion similar to other forms of benign and malignant cutaneous neoplasms. Accurate diagnosis, optimal treatment and prognosis of EPC are still challenging due to scant literature reports. Eccrine carcinomas may have an elevate presence of regional lymph node metastasis, thus some authors have advocated SLNB for all or some patients, but its utility for staging purposes remains unknown.

We report two cases of EPC in which the sentinel lymph node biopsy (SLNB) was performed.

CASE PRESENTATION Case 1 During August 2017, a 64 years woman was seen at our department after a previous cutaneous lesion excision with an histological diagnosis of porocarcinoma of the left thigh. The histological examination revealed a poroid neoplasm extending into the deep dermis to the level of the dermal-subcutaneous junction with a thickness of 5.4mm, 10-12 mitoses per 10 high-power field, absence of lymphovascular invasion and free margins with a clearing distance of 1.5 mm. Hematoxilyn-eosin staining and Immunohistochemical (IHC) analysis showed positive staining for carcinoembryonic antigen (CEA), cytokeratin (CK) 5,7 and epithelial membrane antigen (EMA).

She had a past medical history of appendicitis in childhood, anxious-depressive syndrome, osteoporosis, hiatal hernia, obesity and smoked about 20 cigarettes a day. New York Heart Association (NYHA) score was 1 and American Society of Anesthesiologists (ASA) score was 1. The patient had no anorexia and weight loss and the examination did not reveal any inguinal lymphadenopathy. Laboratory tests, including blood count, biochemical investigations and serological viral markers were normal. The electrocardiogram showed sinus rhythm and the chest radiograph showed no signs of pleural or parenchymal lesions. After multidisciplinary discussion and based on the sub-optimal clearing margin we performed a re-excision of the previous wound to ensure wider safety margins of at least 20 mm similarly to surgical strategy for other skin tumors and in particular melanoma. At that time it was also decided to perform a SLNB; preoperative lymph-node scintigraphy showed the presence of two sentinel lymph nodes in the left groin that were excised during SLNB.

Case 2 During August 2017, a 65year-old female was admitted to our department with histological finding of EPC of the right leg. One month before, she underwent surgical excision of a cutaneous lesion of the right leg. This lesion appeared brownish, exophytic, with ulcerated surface, more suggestive for a squamous cell carcinoma than an ulcerated nodular basal cell carcinoma. The histological examination revealed a poroid neoplasm extending into the reticular dermis with a thickness of 5 mm, 10 mitoses per 10 high-power field, absence of lymphovascular invasion and free margins with a clearing distance of 2 mm.