Clinical Differential Diagnosis
(Remo Lobetti PhD, DECVIM): Differentials include gastrointestinal tract blood loss (neoplasia, foreign body, ulcer), anemia of chronic infection, neoplasia, bone marrow pathology, lead/zinc toxicity, systemic mastocytosis.
Sonographic Differential Diagnosis
(Lindquist DMV, DABVP): Infiltrated descending colon with associated lymphadenopathy. Loss of intestinal mural detail and structural loss in the adjacent lymph node meets neoplastic criteria such as that of lymphoma, mast cell disease, and less likely intestinal carcinoma. Complicated inflammatory disease (IBD) bacterial, fungal, viral colitis, or dry form FIP also possible with associated lymphadenitis.
FNA of both the lymph nodes and the colonic infiltrate were inconclusive, so exploratory surgery and the referring veterinarian performed biopsies.
Primary surgical differential was neoplasia such as lymphoma. However, surgically obtained histopathology was both “characteristic and diagnostic” for FIP. The pathologist described the GI lesions (colon) and the lymph node as “granulomatous, multifocal, moderate; with necrosis”. The laboratory also performed Immunostaining for Feline Coronavirus on the colon, which was positive for FECV.
The patient was put on supportive care post surgery. Patient is doing well 2 months after surgery (Intestinal resection).