Radiology Case

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Radiographic findings: There is a large, lobulated soft tissue opacity measuring approximately 5 x 10 cm in the right ventral abdomen (a). Multiple variably sized gas bubbles are noted superimposed to it. No other significant abnormalities are noted involving the abdominal organs.

Radiographic impression: The radiographic findings are compatible with an intestinal mass.

Comments: The most common intestinal neoplasm in the cat is adenocarcinoma. 1 Adenocarcinoma is usually a circumferential lesion that is seen most commonly in old cats in the ileum and jejunum. 2 Siamese cats usually get the disease most commonly. 3 In 50 % of the cases it will metastasize to the peritoneum, mesentery, and omentum of cats, and abdominal effusion can be seen secondary to the metastasis.

The second most common intestinal neoplasm is lymphoma. Generalized lymphadenopathy is rarely seen in cats with lymphoma. Most cats present with involvement of the intestines/mesenteric lymph nodes, cranial mediastinum, liver, spleen, and kidneys.

Other intestinal neoplasms (list is not exhaustive) in the cat reported less commonly include mast cell tumors, rarely hemangiosarcoma4, and osteosarcoma. 5

The clinical signs of intestinal neoplasia depend on the location in the intestine, duration of the disease, and metastasis. If the small intestine is involved, generally there is a history of vomiting and weight loss. If the large intestine is involved, tenesmus or hematochezia is expected. Physical exam generally reveals a palpable abdominal mass.

Radiographic evidence of an intestinal mass varies. Some can be clearly appreciated and others are discrete. Adenocarcinoma, and less often lymphosarcoma, will have an annular appearance and can be identified if there is gas trapped within the lumen or if an intestinal contrast study is performed. Sonographic evaluation generally enables localization of the mass, evaluation for metastasis, and facilitates guided biopsy. The tumor type guides treatment. 6

References

1. Rivers BJ, Walter PA, Feeney DA, et al. Ultrasonographic features of intestinal adenocarcinoma in five cats. Vet Radiol Ultrasound 1997;38:300-306.
2. Patnaik AK, Liu SK, Johnson GF. Feline intestinal adenocarcinoma. A clinicopathologic study of 22 cases. Vet Pathol 1976;13:1-10.
3. Patnaik AK, Liu SK, Hurvitz AI, et al. Nonhematopoietic neoplasms in cats. J Natl Cancer Inst 1975;54:855-860.
4. Sharpe A, Cannon MJ, Lucke VM, et al. Intestinal haemangiosarcoma in the cat: clinical and pathological features of four cases. J Small Anim Pract 2000;41:411-415.
5. Heldmann E, Anderson MA, Wagner-Mann C. Feline osteosarcoma: 145 cases (1990-1995). J Am Anim Hosp Assoc 2000;36:518-521.
6. Ogilvie GK, Moore AS. Managing the veterinary cancer patient: a practice manual. Trenton, NJ: Veterinary Learning Systems, 1995.

Dr. John Feleciano, DVM, DACVR
Dr. Renee Leveille, DVM, DACVR

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