Rare Case of Systemic Cryptococcal Lymphadenopathy in a Persian Cat.

Background: Cryptococcosis is the most common systemic fungal infection in cats, typically presenting with respiratory or neurological signs. However, cases without these hallmark symptoms are rare and often misdiagnosed. This case is noteworthy for its atypical presentation, where a cat developed systemic cryptococcosis without the typical respiratory or neurological involvement, making it particularly challenging to diagnose. In addition, the overlap of clinical signs with other diseases like lymphoma underscores the importance of considering cryptococcosis in differential diagnoses.

Case presentation: A 7-year-old castrated male Persian cat was referred due to generalized cutaneous nodules, including a prominent 4-5 cm nodule on the neck, and generalized lymphadenopathy. Neurological examination revealed an absent menace response in the left eye, raising suspicion of vision loss. Blood tests indicated hyperglobulinemia and the presence of medium-to-large lymphoid cells in the peripheral blood. Diagnostic imaging showed systemic lymphadenopathy, retinal detachment and minimal ascites. Fine needle aspiration of the lymph nodes revealed yeast-like organisms, and culture confirmed Cryptococcus neoformans. Initially treated with itraconazole, the therapy was switched to fluconazole due to better CNS penetration. The lymph node enlargement improved within one week, but further follow-up was limited due to owner constraints.

Conclusions: This case emphasizes the diagnostic challenges posed by atypical presentations of feline cryptococcosis, particularly in the absence of respiratory and neurological symptoms. It highlights the importance of considering systemic fungal infections in the differential diagnosis of lymphadenopathy. The overlap with diseases like lymphoma further underscores the need for comprehensive diagnostic workups, including cytology and culture, to ensure accurate diagnosis and effective treatment.