Cutaneous apocrine carcinoma in groin with bilateral lymph node metastasis: a case report and review of the literature.

Cutaneous apocrine carcinoma (CAC) is a rare type of malignant adnexal tumour with only scattered reports. We report a 52-year-old male patient of CAC in groin with bilateral lymph node metastasis. The patient had a left inguinal subcutaneous mass 3 cm × 2 cm in size for 4 years, and received a wide local excision of the tumour. Pathological sectioning suggested CAC. The immunohistochemical staining revealed GCDFP15 (+), 34BE12 (+), ER (+), PR (+), CK7 (+), Ki67 (5%-10%), HER2/Neu (-), P53 (-), P63 (-), and CK20 (-). Two subcutaneous masses of 2 cm × 1 cm were found below the original incision 10 months after the operation, and regional lymphadenectomy was performed. During the outpatient follow-up, B-ultrasound examination showed abnormal enlargement of the right inguinal lymph nodes 17 months later, and right inguinal lymphadenectomy was performed. No evidence of recurrent or metastasis disease has been seen after a follow-up period of 16 months till now. We review the literature on pathological and immunohistochemical study of CAC and discuss its diagnostic dilemma.