The fistula-associated anal adenocarcinoma is rare in patients suffering from anal fistulas. There is only little data available for this patient collective making characterization and management of this disease difficult. Late diagnosis and advanced tumor stage at diagnosis result in poor clinical outcome. It is the purpose of this study to evaluate patients clinically diagnosed with a FAAC and to further perform a histopathological characterization of the available tumor specimen.

All patients receiving surgery for an anal fistula in the years 1999 to 2019 at a tertiary university referral hospital were included in the analysis. A retrospective review of patients' charts was performed. Patients suffering from FAAC were eligible for histopathological analysis including immunohistochemistry and molecular profiling.

Inclusion Criteria:

• anal fistula

Exclusion Criteria:

• previous cancer of the anal canal

all patients receiving surgery for an anal fistula at a tertiary university referral hospital. Of those, patients suffering from fistula-associated anal cancer were eligible for further clinical and histopathological analysis