Cytology Q&A 10

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An eight-year-old female spayed DSH cat presented with a two-week history of intermittent vomiting. There was an acute onset of lethargy and anorexia. Significant findings on physical examination included icterus and severe hepatomegaly. CBC findings included moderate, nonregenerative anaemia (PCV = 0.23 l/l). Abnormal biochemistry findings were: ALT = 360 U/l (ref. = 10–80 U/l); ALP = 120 U/L (ref. = 2–43 U/l); bilirubin = 55 μmol/l (ref. = 0–3.4 μmol/l). An FNA of the liver was obtained and a smear made (Wright–Giemsa, ×25).

Question	Answer		Article
Describe the cytological findings, and give your cytological interpretation.	The smear contains several hepatocytes with round to oval nuclei and light basophilic cytoplasm. A single distinct prominent nucleolus characteristic of hepatocytes is also present. Large numbers of well-differentiated lymphocytes are present around the hepatocytes and in the background. Lymphocytes are discrete cells with a small amount of cytoplasm. Nuclei are round and are about one to one and a half times the size of erythrocytes. Nuclear chromatin is dense and clumped. The cytological interpretation is a well-differentiated hepatic lymphoma.		[[|Link to Article]]
Discuss the condition.	Many cats with hepatic lymphoma will present cytologically with an abundant population of small, well-differentiated lymphocytes. It is important to differentiate lymphocytic periportal hepatitis from hepatic lymphoma. Cats with hepatic lymphoma usually have severe hepatomegaly, whereas with lymphocytic periportal hepatitis, hepatomegaly is typically mild. Histological confirmation is recommended in cats with severe lymphocytic infiltrates and marked hepatomegaly, regardless of the cytological appearance of the lymphocytes.		[[|Link to Article]]
Discuss the prognosis and treatment options.	Treatment options include chemotherapy. In a few isolated cases where the tumour is localized and easily accessible, surgery or radiation therapy may be used. A combination of chemotherapeutic drugs, including doxorubicin, cyclophosphamide and vincristine, and prednisone, administered over many weeks is the most common course of treatment. During the course of treatment leukocyte and erythrocyte numbers are closely monitored. The remission and survival rates of cats with lymphoma vary depending on the cat’s FeLV status, the location of the tumour(s) and how quickly the tumour is diagnosed and treated. In general, about 70% of cats will respond to the chemotherapy protocol. On average, these cats will live an additional 4–6 months. However, about 30–40% of the cats that respond will go into a more complete remission that can last for two years or longer. Cats that are not treated have an average survival time of only 4–6 weeks once the diagnosis has been made. Note: As pointed out above, the small lymphocytes illustrated in this case do not have features associated with classical lymphoid malignancy (large numbers of large lymphocytes and lymphoblasts) as is usually seen in the dog. It is important to include well-differentiated or so-called ‘small cell’ lymphoma in your differential diagnosis list in addition to lymphocytic periportal hepatitis when lymphocytes are numerous in a hepatic aspirate.		[[|Link to Article]]