Rhinofacial pythiosis with pulmonary and lymphatic dissemination in a Uruguayan horse

ABSTRACT: We described the first case of rhinofacial pythiosis with dissemination in an adult horse in Uruguay. The affected horse presented a partially circumscribed mass measuring 30 x 23 x 9 cm affecting the right side of the face with involvement of cutaneous, subcutaneous, and muscular tissues, the right nasal cavity, and adjacent structures. At postmortem examination, the main lesions were “kunkers” characterized by pyogranulomatous and eosinophilic dermatitis, Splendore-Hoeppli reaction and numerous intralesional hyphae immunolabeling with polyclonal anti-Pythium insidiosum antibody. Similar lesions were observed in the lung and submandibular lymph nodes. The diagnosis was made by the characteristic histological lesions and the strong immunolabelling by anti-P. insidiosum antibody.