Systemic infection with Geomyces organisms in a dog with lytic bone lesions

Case Description - A 5-year-old neutered male mixed-breed dog was evaluated by a veterinarian because of a 4-week history of progressive lethargy and poor appetite; the dog was then examined at a referral hospital. Clinical Findings - Hyperglobulinemia was identified via serum biochemical analyses performed before and after arrival at the hospital. Lysis of sternebrae 1 and 2 and sternal lymphadenopathy were detected radiographically. Fine-needle aspirates were collected from the affected sternebrae and lymph node for cytologic examination; findings were consistent with pyogranulomatous inflammation associated with fungal infiltrates. Geomyces organisms were identified via microbial culture of sternebral aspirates. Treatment and Outcome - Treatment consisted of oral administration of itraconazole. After 6 months, remodeling of the affected sternebrae and resolution of sternebral lysis were evident radiographically, Geomyces organisms and pyogranulomatous infiltrates persisted despite clinical improvement. Treatment with itraconazole was continued for an additional 3 months. Clinical Relevance - Infection with Geomyces organisms is typically localized to the skin and nail beds. In the dog of this report, systemic dissemination of Geomyces organisms resulted in lysis of the first 2 sternebrae. Cytologic examination of fine-needle aspirates and microbial culture of samples of the affected sternebrae were important diagnostic tests for successful identification of the organism. Despite 6 months of itraconazole administration and evidence of clinical improvement, fungal organisms persisted in the dog's affected sternebrae. Practitioners should include Geomyces infection among the differential diagnoses for suspected systemic mycosis and should perform cytologic examination and microbial culture of affected tissue throughout treatment of affected dogs.