Snowball, a 12-year-old, M/N, Ragdoll cat presented with a history of vomiting for three days. Blood work was unremarkable. AUS showed thickening within the duodenum (r/o focal enteritis vs. infiltrative neoplasia). Liver enlarged and uniformly hyperechoic. FNA from the liver is submitted.
Scopio Practice Tip
Cellular areas in liver (and splenic) aspirates often appear as thicker blue clumps. The user chosen scan area below is an ideal choice and an additional area of interest is circled. Mast cells may stain poorly with Diff Quick, but when this occurs, they often prove to be variably granulated with Wright Giemsa staining as well. A combination of morphology and evidence of granulation often allows for mast cell neoplasia interpretation using Diff Quick stained slides.
Webcam images with user chosen scan area denoted by thin green line.
Hepatocytes (green/blue tinged cytoplasm) with poorly granulated mast cells.
Mast cells exhibiting variable granulation and/or decreased stain uptake.
Interpretation: Hepatic mast cell neoplasia.
Notes regarding mast cell neoplasia in cats:
- On cytologic exam, MCT in cats tends to exhibit greater cellular atypia than in dogs.
- Feline eosinophilic sclerosing fibroplasia can mimic MCT in intestinal lesions.
- Feline cutaneous mast cell tumors are not yet graded, but this has been recently investigated.
- MCT may be more common in this breed, as well as in Siamese cats.
Clinical follow up: This patient presented to emergency service and was transferred to the oncology service the following morning. Given the prognosis, and additional history that this cat’s mother and littermate also died of mast cell neoplasia, humane euthanasia was elected.
Reference & Suggested Clinic Resource: Sabattini S, Bettini G. Grading cutaneous mast cell tumors in cats. Vet Pathol. 2019 Jan;56(1):43-49.
Craig LE, Hardam EE, Hertzke DM, et al. Feline gastrointestinal eosinophilic sclerosing fibroplasia. Vet Pathol. 2009 Jan;46(1):63-70.
Melville K, Smith KC, Dobromylsky MJ. Feline cutaneous mast tumours: a UK-based study comparing signalment and histological features with long-term outcomes. J Feline Med Surg. 2015 Jun;17(6):486-93.