Page 1261 - Cote clinical veterinary advisor dogs and cats 4th

632 Mast Cell Tumors, Cat

○ Splenectomy prevents exsanguination. SUGGESTED READING AUTHOR: Jacob A. Rubin DVM, DACVS
○ Splenectomy improves the quality of Thamm DG: Hemangiosarcoma. In Withrow SJ, et EDITOR: Elizabeth A. Swanson DVM, MS, DACVS
VetBooks.ir diagnosis, it may not prolong life. al, editors: Withrow and MacEwen’s Small animal
life for the patient, but depending on
clinical oncology, St. Louis, 2013, Saunders, pp
679-684.

Mast Cell Tumors, Cat Client Education
Sheet

BASIC INFORMATION RISK FACTORS • A unique form of feline visceral MCT is
Mutations in the proto-oncogene KIT have feline intestinal sclerosing MCT, a primary
Definition occurred in feline MCT and may predispose GI mass histologically characterized by GI
Mast cell tumors (MCTs) are neoplastic cats to MCT development. mucosal ulceration, eosinophilic infiltrates,
accumulations of mast cells. MCTs produce and poorly granulated MCTs.
deleterious effects when mast cells degranulate, ASSOCIATED DISORDERS
resulting in release of bioactive substances that Related to mast cell degranulation: HISTORY, CHIEF COMPLAINT
can produce cutaneous or systemic effects, • GI ulceration • Most cats with cutaneous MCTs are
depending on tumor location. Cutaneous MCTs • Pruritus, cutaneous flushing, peritumoral asymptomatic, although some lesions are
are common. Visceral MCTs include splenic edema, bruising pruritic and have peritumoral edema or
MCTs (uncommon) and gastrointestinal (GI) • Delayed wound healing bruising. MCTs often remain unchanged
MCTs (rare). Related to visceral MCT (especially splenic): in appearance for years.
• Pleural or abdominal cavity effusion (often • Cats with visceral MCTs display nonspe-
Synonyms containing mast cells) cific signs of illness (weakness, lethargy,
Mastocytoma, splenic or visceral mastocytosis anorexia) or GI ulceration–associated
Clinical Presentation
Epidemiology DISEASE FORMS/SUBTYPES bruxism, vomiting, diarrhea, weight loss,
and melena. Abdominal distention second-
SPECIES, AGE, SEX In cats, there are several distinct presentations: ary to effusion and splenomegaly may also
• Primarily a disease of older cats, although • Cutaneous MCT (solitary or multiple) occur.
all ages can be affected • Splenic (i.e., visceral MCT; splenomegaly,
• Information on MCTs in dogs is provided occasionally concurrent with hepatic and/ PHYSICAL EXAM FINDINGS
on p. 634. or bone marrow infiltration, and abdominal • Although most cutaneous MCTs are found
effusion) on the head/neck, a thorough exam of the
GENETICS, BREED PREDISPOSITION • GI MCT (i.e., visceral MCT; commonly skin is indicated. Tumors are usually alo-
Siamese (possibly) with hepatic and mesenteric lymph node pecic, small (<5 mm), round, and pink or
[LN] infiltration) white. Some MCTs are plaquelike. Regional

A B
MAST CELL TUMORS, CAT A, Note the hairless, red MCT on the right dorsal eyelid. B, MCTs on the face and
neck. On further exam, this cat had numerous cutaneous MCTs and splenic involvement.

www.ExpertConsult.com