A 3-year-old spayed female Labrador Retriever was presented for right prescapular lymphadenomegaly. Examination of fine-needle aspirates and impression smears of the node revealed many short hyphal structures found within macrophages and extracellularly. Hyphae were approximately 3 μm in diameter, were irregularly septate with nonparallel walls, and had a small clear halo surrounding a partially stained basophilic internal structure. Hyphae were tapered on one end and had oval to pyriform swellings of 7-10 μm on the other, resulting in a bulbous appearance. Fungal elements stained positively with Gomori methenamine silver and Periodic acid-Schiff stains. The dog was euthanized at the owner's request, and necropsy revealed marked peripheral and visceral lymphadenomegaly. Histopathologic examination of lymph nodes confirmed granulomatous lymphadenitis with many fungal hyphae. Fungal culture yielded pure cultures of organisms that failed to produce ascospores or conidia precluding morphologic identification. PCR was performed using pan-fungal primers, ITS-1 and ITS-2, to amplify the intergenic spacer regions of ribosomal RNA; the PCR product was sequenced and a BLAST search of the GenBank databases at NCBI revealed 100% identity of the organism with Talaromyces helicus, the sexual form of Penicillium helicum. Talaromyces helicus has not previously been reported to cause disease in people or animals.

A 5-year-old intact female potbellied pig presented for a 2-week history of anorexia, lethargy, and intermittent fever. Over 2 months, serial complete blood count evaluations revealed a persistent, progressive, marked basophilia and differential diagnoses included parasitism, hypersensitivity reaction, paraneoplastic response, or basophilic leukaemia. The patient was diagnosed with basophilic leukaemia based on the persistent, marked basophilia and exclusion of other differentials. Due to possible inconsistencies in basophil identification by automated haematology analysers, blood smear examination must be performed to quantify circulating basophils. Diagnosis of basophilic leukaemia is based on light microscopic examination of blood and/or bone marrow and exclusion of other differentials. While basophilic leukaemia is rare in veterinary medicine, it should be considered a differential for a marked, persistent basophilia in any species. This case highlights some of the challenges associated with diagnosing and treating this disorder.