Colonic adenocarcinoma in an 11 year old FS Siamese cat

History

This 11-year-old FS Seal Point Siamese cat was presented for dyschezia. The physical exam revealed palpable stool impaction and a ropey intestine. The CBC and blood chemistry analysis were normal.

This 11-year-old FS Seal Point Siamese cat was presented for dyschezia. The physical exam revealed palpable stool impaction and a ropey intestine. The CBC and blood chemistry analysis were normal.

Clinical Differential Diagnosis

Constipation, inflammatory bowel disease, colitis, neoplasia, pancreatitis, intestinal obstruction.

DX

Colonic adenocarcinoma

Sampling

22-ga US-guided FNA of the lesion revealed mixed inflammation and normal epithelial cells. Partial colectomy was performed, with biopsy analysis revealing colonic adenocarcinoma with mural invasion. Biopsy of associated enlarged lymph nodes demonstrated only reactive hyperplasia without evidence of metastasis.

Sonographic Differential Diagnosis

Chronically, partially obstructing annular descending colonic wall mass consistent with neoplasia and adenocarcinoma is primarily suspected.

Image Interpretation

There is an asymmetrical, moderate to severe descending colonic mural thickening with complete loss of wall layering. A non-uniform, long zone transition from normal to abnormal bowel is noted. The lumen proximal to the mass is mildly distended with echogenic, faintly shadowing fecal matter. Close inspection of the unaffected wall demonstrates thickening which may be the result of hypertrophy secondary to chronic partial obstruction.