Malignant histiocytosis in a domestic cat: cytomorphologic and immunohistochemical features

• Published in: Veterinary clinical pathology Vol. 26; no. 2; pp. 56 - 60
• Main Authors: Walton, R.M. (Colorado State University, Fort Collins, CO.), Burkhard, M.J, Donnelly, K.B, Frank, A.A, Obert, L.A, Withrow, S.J, Thrall, M.A
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.01.1997
• Subjects: BLOOD DISORDERS; CASE STUDIES; CATS; CHAT; CITOLOGIA; CYTOLOGIE; CYTOLOGY; ESTUDIOS DE CASOS PRACTICOS; ETUDE DE CAS; Feline; GATO; HISTOPATHOLOGIE; HISTOPATHOLOGY; HISTOPATOLOGIA; IMMUNOCYTOCHEMISTRY; IMMUNOLOGIE; IMMUNOLOGY; INMUNOLOGIA; malignant histiocytosis; NEOPLASMAS; NEOPLASME; NEOPLASMS; TRASTORNOS SANGUINEOS; TROUBLE SANGUIN
• ISSN: 0275-6382; 1939-165X
• DOI: 10.1111/j.1939-165X.1997.tb00708.x

Malignant histiocytosis (MH) was diagnosed in a 13‐year‐old neutered male Domestic Shorthair cat on the basis of light microscopic and immunohistochemical findings. Thoracic fluid analysis showed a modified transudate which contained a very few atypical discrete cells. Cytologic and histologic evaluation of mediastinal and splenic masses revealed a pleomorphic population of large, discrete, round cells 10 to 30 βm in diameter with marked cellular atypia. Nuclei were oval to reniform, often with prominent, bizarre nucleoli. Multinucleated cells and mitotic figures were commonly seen. Erythro‐and leucocytophagia were noted. Immunohistochemistry indicated a scattered positive staining pattern with the histiocytic antigenic marker Mac387 and a minor population of cells showing positive reactivity for lysozyme. This report describes the characterization of MH in a cat and emphasizes that MH should be considered as a differential diagnosis in proliferative disorders of discrete cells in this species.