Malassezia spp. overgrowth in allergic cats.

A series of 18 allergic cats with multifocal Malassezia spp. overgrowth is reported: atopic dermatitis was diagnosed in 16, an adverse food reaction in another and one was euthanized 2 months after diagnosis of Malassezia overgrowth. All the cats were otherwise healthy and those tested (16 out of 18) for feline leukaemia or feline immunodeficiency virus infections were all negative. At dermatological examination, multifocal alopecia, erythema, crusting and greasy adherent brownish scales were variably distributed on all cats. Cytological examination revealed Malassezia spp. overgrowth with/without bacterial infection in facial skin (n = 11), ventral neck (n = 6), abdomen (n = 6), ear canal (n = 4), chin (n = 2), ear pinnae (n = 2), interdigital (n = 1) and claw folds skin (n = 1). Moreover, in two cats Malassezia pachydermatis was isolated in fungal cultures from lesional skin. Azoles therapy alone was prescribed in seven, azoles and antibacterial therapy in eight and azoles with both antibacterial and anti-inflammatory therapy in three of the cats. After 3-4 weeks of treatment, substantial reduction of pruritus and skin lesions was observed in all 11 cats treated with a combined therapy and in five of seven treated solely with azoles. Malassezia spp. overgrowth may represent a secondary cutaneous problem in allergic cats particularly in those presented for dermatological examination displaying greasy adherent brownish scales. The favourable response to treatment with antifungal treatments alone suggests that, as in dogs, Malassezia spp. may be partly responsible for both pruritus and cutaneous lesions in allergic cats.

Feline lymphangiosarcoma--definitive identification using a lymphatic vascular marker.

Three cases of feline exudative dermatitis associated with lymphangiosarcoma are described. The animals, an 11-year-old, neutered male and two 10-year-old, neutered female short hair European cats, presented with a 2-month history of transparent liquid oozing from the skin of the groin and caudal abdomen. On physical examination the neutered male cat and one of the females were slightly depressed and showed loss of weight. Skin lesions were similar in all cats and characterized by the presence of alopecia and moist dermatitis in the ventral abdomen, groin and inner thigh. The hair at the periphery appeared matted by the fluid. In all three cases, histopathological examination of skin biopsies from the abdomen identified poorly defined neoplasia involving dermis and subcutis, characterized by proliferation of spindle cells aligned along pre-existing collagen bundles. The dissection of collagen bundles gave rise to irregular shaped anastomosing, often blind-ending vascular channels and trabeculae. Vascular spaces were mostly optically empty. These histological features were strongly suggestive of lymphangiosarcoma. Neoplastic cells were positive for the blood vascular marker Von Willebrand factor, and a lymphatic vascular marker LYVE-1 (Lymphatic Vessel Endothelial receptor - 1), demonstrating the mixed vascular origin of the tumour. Ultrastructural findings confirmed the final diagnosis of lymphangiosarcoma.