61 - SAM

What clinical signs in a cat should raise suspicion for gastrointestinal lymphoma?

Weight loss

What abdominal ultrasound findings are particularly suspicious for lymphoma in a cat?

Marked intestinal wall thickening

What cytologic findings support a diagnosis of large-cell lymphoma?

Monomorphic population of intermediate to large lymphoid cells with possible mitotic figures

Why is loss of intestinal wall layering concerning on ultrasound?

It indicates disruption of normal intestinal architecture and can be associated with an infiltrative neoplastic process such as lymphoma

What is the most common anatomical location of lymphoma in cats compared with dogs?

Cats = gastrointestinal tract

What are the two major forms of feline lymphoma and what clinical presentation can small-cell lymphoma mimic?

Large-cell and small-cell lymphoma

What is the first-line chemotherapy protocol for feline lymphoma?

CHOP

What is the major prognostic difference between large-cell and small-cell feline lymphoma?

Large-cell has a median survival of 6-8 months

What does a rapidly growing mass at a previous vaccination site in a cat raise suspicion for?

Feline injection-site (vaccine-site) sarcoma

What is the recommended initial diagnostic test for a suspected feline injection-site sarcoma?

Fine needle aspirate looking for spindle-cell proliferation

Why is fine needle aspiration preferred initially over biopsy for a suspected injection-site sarcoma in this lecture?

It is less expensive

What cytologic characteristics support a diagnosis of a malignant mesenchymal tumor?

Cells are not adherent

Why are injection-site sarcomas particularly difficult to treat surgically?

They are highly invasive and send microscopic extensions into surrounding tissues beyond the visible mass

What is the preferred advanced imaging modality for evaluating the local extent of an injection-site sarcoma before surgery?

CT scan

What surgical margins are recommended for feline injection-site sarcoma?

3-5 cm in all directions when possible, including appropriate deep fascial planes

What is the most important prognostic factor following surgical removal of an injection-site sarcoma?

Extent and completeness of surgical margins

What is the gold-standard additional treatment for improving local control of injection-site sarcoma?

Radiation therapy

Which chemotherapy drug may be considered for injection-site sarcoma?

Doxorubicin

Why is complete staging important before treating an injection-site sarcoma?

To evaluate for metastatic disease and determine the extent of the primary tumor before planning treatment

What is the major difference between local recurrence and metastatic behavior in feline injection-site sarcoma?

These tumors are especially aggressive locally due to extensive tissue invasion, although they can also metastasize (up to approximately 25%)