Abstract Fistula-associated anal adenocarcinoma (FAAC) is an uncommon disease. Due to the clinical similarity in the symptoms to benign anal fistulas, FAAC can confuse clinicians and lead to delayed diagnosis. We report a case of FAAC in a patient with a 20-year history of an unhealed perianal fistula and who had recently been diagnosed with thrombocytopenia, hepatitis C, liver cirrhosis, and splenomegaly. He presented with a painful, indurated perianal fistula-producing bloody discharge which concealed an adenocarcinoma. In this report, we describe how the atypical clinical features prompted an initial biopsy via curettage and outline the therapeutic strategies for advanced FAAC. The primary tumor demonstrated a 14% reduction in size following multimodality treatment, including concurrent chemoradiotherapy and subsequent systemic chemotherapy with targeted therapy. However, rapid disease progression with metastases to both lungs and para-aortic lymph nodes ultimately led to the patient’s death. This case underscores the diagnostic challenges and aggressive nature of FAAC.
Lin et al. (Thu,) studied this question.