Metastatic cancer of unknown primary in 21 dogs.

The aim of this retrospective study was to describe clinical features, treatment and outcome of 21 dogs with metastatic cancer of unknown primary (MCUP), a biopsy-proven malignancy being diagnosed at a metastatic stage, in which the anatomical origin of the primary tumour cannot be detected. All dogs underwent total-body computed tomography. Signalment, type and duration of clinical signs, metastasis site, pathology results, treatment and outcome were recorded. Carcinoma was the most common diagnosis (57.1%), followed by sarcoma, melanoma and mast cell tumour. The median number of disease sites per dog was 2, with bones, lymph nodes, lungs and spleen being the most frequent metastatic locations. The median survival for all dogs was 30 days. Overall, a primary site was not identified in 20 (95.2%) dogs. MCUP encompasses a variety of different pathologic entities and harbours a poor prognosis.

Ultrasonography of intestinal mast cell tumors in the cat.

The sonographic features of intestinal mast cell tumors (MCT) were reviewed in 14 cats. The mean age was 13.4 ± 2.5 years. There were 16 focal intestinal tumors and one diffuse submucosal infiltrate. The most common pattern was focal, hypoechoic wall thickening that was noncircumferential and eccentric (9/16 tumors) or circumferential, asymmetric, and eccentric (5/16 tumors). Nine of the cats had lesions in the jejunum or duodenum, four were at the ileocecocolic junction, and one cat had a colonic mass. Six MCTs had altered but not loss of wall layering, and the most commonly affected layer on ultrasound examination was the muscularis propria. Nine cats had enlarged abdominal lymph nodes, and seven were due to metastatic disease. Metastatic disease was not routinely detected by ultrasound in the liver (1/4 cats) or the spleen (0/3 cats). Concurrent small cell (T cell) lymphoma was present in four of 14 cats (29%).