Cutaneous and visceral phaeohyphomycosis in an immunocompetent golden retriever

A 3-year-old castrated male golden retriever was presented for evaluation of 2 cutaneous masses along the abdominal midline and a 6-month history of progressive lethargy and inappetence. Two years earlier, the dog underwent a gastrotomy to retrieve a foreign object and recovered uneventfully. Fluid aspirated from the lesions was culture-negative for aerobic and anaerobic bacterial growth. Abdominal ultrasound demonstrated a large intra-abdominal mass with apparent communication with the cutaneous lesion, along with gossypiboma from the previous laparotomy. Neoplasia or a sterile abscess were suspected. Exploratory laparotomy was performed and revealed that the intra-abdominal mass was adhered to the abdominal midline and the greater curvature of the stomach. The masses and affected portions of the body wall and stomach were resected and histopathology was consistent with phaeohyphomycosis. Antifungal therapy with voriconazole (6.3 mg/kg, PO, q12h) was initiated. At 1 mo after surgery, all clinical signs had resolved. At 4 and 7 mo after surgery, the dog continued to thrive despite 2 small masses, seen on abdominal ultrasound imaging on the intra-abdominal midline, suggestive of reoccurrence. Continued voriconazole therapy was administered in lieu of further surgical excision. One year after surgery, the masses were no longer present on ultrasonographic evaluation. Phaeohyphomycosis is a rare, opportunistic fungal infection that typically affects the dermis and subcutis of immunocompromised dogs. This is the first report of phaeohyphomycosis in an immunocompetent dog and involving the dermis, subcutis, and abdominal viscera. Key clinical message: This case adds to the very limited literature on phaeohyphomycosis in dogs and illustrates that surgery could be a risk factor for infection, even in dogs with no known underlying disease or immunodeficiency.