Disseminated cutaneous mast cell tumors with epitheliotropism and systemic mastocytosis in a domestic cat

• Published in: Journal of veterinary diagnostic investigation 2009-09, Vol.21 (5), p.710-715
• Main Authors: Lamm, Catherine G, Stern, Adam W, Smith, Amanda J, Cooper, Emily J, Ullom, Steven W, Campbell, Gregory A
• Format: Article
• Language: English
• Subjects: Animals; Anti-Bacterial Agents - therapeutic use; bone marrow; case studies; cat diseases; Cats; cytoplasm; disease diagnosis; epithelium; Exons; Female; Fetus; immunohistochemistry; lesions (animal); liver; mast cells; Mast Cells - pathology; mastocytosis; Mastocytosis - complications; Mastocytosis - genetics; Mastocytosis - pathology; Mastocytosis - veterinary; Mastocytosis, Systemic - complications; Mastocytosis, Systemic - genetics; Mastocytosis, Systemic - pathology; Mastocytosis, Systemic - veterinary; messenger RNA; molecular sequence data; Mycoses - drug therapy; Mycoses - veterinary; neoplasms; pets; Prednisone - therapeutic use; Proto-Oncogene Proteins c-kit - genetics; reverse transcriptase polymerase chain reaction; RNA, Messenger - genetics; sequence analysis; signs and symptoms (animals and humans); skin; Skin Diseases - drug therapy; Skin Diseases - microbiology; Skin Diseases - pathology; Skin Diseases - veterinary; Skin Neoplasms - complications; Skin Neoplasms - genetics; Skin Neoplasms - pathology; Skin Neoplasms - veterinary; spleen
• ISSN: 1040-6387; 1943-4936
• DOI: 10.1177/104063870902100520

Correspondence: 1 Corresponding Author: Catherine G. Lamm, OADDL, PO Box 7001, Stillwater, OK 74076. cathy.lamm{at}okstate.edu A 15-year-old female domestic, medium-haired cat presented to the referring veterinarian with a 2-month history of multiple, raised, disseminated, nodular skin lesions. A biopsy of 1 of the lesions was submitted to the Oklahoma Animal Disease Diagnostic Laboratory for evaluation. Histologically, there were multiple dermal nodules composed of sheets of neoplastic round cells. Multifocally, the neoplastic cells formed multiple small clusters of 3 to 5 cells within the epidermis. Distinct cytoplasmic granules were evident within the neoplastic cells with toluidine blue and Giemsa stains. The neoplastic cells were immunoreactive for c-KIT and lacked immunoreactivity for cluster of differentiation 3 with immunohistochemistry. Based on these findings, multiple epitheliotropic cutaneous mast cell tumors were diagnosed. The cat's health declined rapidly despite aggressive treatment, and the animal was humanely euthanatized. A complete necropsy revealed sheets of similar neoplastic mast cells within the spleen, liver, and individual cells scattered within the bone marrow. Exon 11 of the c-KIT messenger RNA from 1 of the cutaneous masses and the spleen was amplified with reverse transcription polymerase chain reaction, sequenced, and compared with the published c-KIT messenger RNA sequence from fetal cat tissues. The maximum identity was 100% for both tissue samples. To the authors' knowledge, the present report is the first to describe disseminated cutaneous mast cell tumors with epitheliotropism and systemic mastocytosis in a domestic cat. Key Words: Cats • epitheliotropic • mast cell tumor • mastocytosis • neoplasm • skin