Abstract
INTRODUCTION: Syringocystadenocarcinoma papilliferum is an extremely rare malignant adnexal tumor that typically arises from a papilliferous syringocystadenoma (World Health Organization classification of skin tumors, 2018.). This tumor predominantly occurs in the cephalic region. CASE PRESENTATION: We present the case of a 68-year-old Moroccan male with no significant medical history who presented with a slowly progressing skin mass in the perianal region. Despite the chronic nature of the swelling, the patient remained in overall good health. Physical examination revealed a firm 2.3-cm mass in the perianal area, with no other remarkable findings. The patient underwent surgical excision of the mass. Macroscopic examination showed a solid-cystic, rounded mass. Microscopic examination revealed a malignant adnexal tumor with apocrine differentiation and papillary architecture. Immunohistochemistry was positive for p63, cytokeratin 7 (CK7), and smooth muscle actin, with a Ki67 labeling index in 60% of tumor cells, and negative for p16. The diagnosis of syringocystadenocarcinoma papilliferum was confirmed. A further surgical resection was performed, and the patient's postoperative course was unremarkable. CONCLUSION: Syringocystadenocarcinoma papilliferum is an extremely rare tumor, with its occurrence in the perianal region being particularly uncommon. This case contributes to the limited literature on this malignancy, highlighting its clinical and pathological features.