Fox Den Disease: An Interesting Case Following Delayed Diagnosis

Pyoderma fistulans sinifica, also known as fox den disease, is a rare and poorly understood inflammatory disorder of the skin and subcutaneous tissues. This disorder is often mistaken for other inflammatory skin disorders and treated inappropriately. The authors describe the case of a 53-year-old male who presented to the colorectal surgery service with a longstanding diagnosis of perirectal Crohn's disease. Despite aggressive immunosuppression and numerous surgical procedures, the patient continued to have unrelenting purulent drainage from the skin of his buttocks. Following wide excision of the affected skin and subcutaneous tissues by the colorectal surgeon, the plastic surgery team reconstructed the 30 cm x 55 cm wound using a combination of local flaps and skin grafts. The initial pathology report of the excised specimen confirmed the presence of nonspecific abscesses and inflammation. Upon special request by the plastic surgery team, the sample was resectioned with the specific intent of establishing a diagnosis of fox den disease. The additional slides met the criteria for an unequivocal diagnosis of fox den disease. Immunosuppression was discontinued and the patient healed his wounds without complication. Fox den disease is often overlooked because of the obscurity of the disease and the special histological sectioning needed to establish a diagnosis. In this case, the patient was unnecessarily treated with immunosuppressive drugs for more than 3 decades because of a misdiagnosis. With increased awareness of fox den disease, perhaps its pathophysiology can be better elucidated as more patients are appropriately diagnosed and treated.