Clinicopathological Features of Syringocystadenoma Papilliferum and Its Malignant Counterpart: A Single-Center Experience

Purpose: Syringocystadenoma papilliferum (SCAP) is a rare benign adnexal tumor with a distinctive histomorphology. Occasionally, there is a diagnostic difficulty, especially in separating it from its malignant counterpart, syringocystadenocarcinoma papilliferum (SCACP). Our study was designed to assess the clinicopathological features of SCAP and to identify features that could help differentiate it from its malignant counterpart at the other end of the spectrum.Materials and methods: A retrospective analysis of 11 SCAP cases and one SCACP case diagnosed over a 15-year period at a single institution was performed. Clinical data and histopathological features were evaluated, and statistical analyses were conducted to assess associations between selected variables.Results: The cohort had a slight female predominance (54.5%) with a mean age of 46.5 years. The most common site was the scalp, with rare sites including the axilla and scrotum. All cases showed classic histological features of prominent papillary architecture and abundant plasma cell infiltrates. Endophytic growth was the predominant pattern (72.7%). Ulceration was observed in 4 cases, including the malignant case. Notably, benign cases exhibited up to 5 mitoses and minimal atypia in 45.5% of cases, with no significant correlation between mitotic activity and atypia. A case of SCACP was diagnosed based on infiltrative growth and atypia.Conclusion: Our study indicates that mitotic activity and mild atypia, by themselves, do not predict malignancy; infiltrative growth and other features of aggressive behavior need to be considered. Larger studies need to be designed to refine these criteria.Keywords: Adnexal neoplasms, syringocystadenoma papilliferum, syringocystadenocarcinoma papilliferum