Case Study

Mast cell disease diagnosed by FNA of mesenteric lymph nodes in a 9 year old MN DSH cat

A 9-year-old MN DSH was presented for the evaluation of lethargy, and vomiting. The cat had been previously diagnosed with multiple cutaneous mast cell tumors. He also had a history of receiving Depo-medrol injections. The cat was febrile and had a painful abdomen on palpation. Previous blood work had shown an elevation of the ALT enzyme activity. Serum biochemistry revealed a high ALT and hyperglycemia. No abnormalities were noted on the CBC. The urine had a cloudy appearance. The urine pH was within the normal reference range, but the specific gravity was elevated and there were a few amorphous urates. A urine microalbumin was negative. The buffy coat evaluating for the presence of mast cells was negative.

DX

Mast cell neoplasia

Sonographic Differential Diagnosis

Aggressive mesenteric root lymphadenopathy was evident with hypervascular pattern and peripheral inflammatory pattern. Given the history, visceral mast cell disease is of primary concern. Lymphoma, FIP, aggressive lymhadenitis should also be considered.

Image Interpretation

A dramatically hypoechoic and micronodular lymph node enlargement was present in the mesenteric root with surrounding hypervascular mesenteric artery and tributaries. The lymph node has lost internal curvilinear architecture and possesses hypoechoic parenchyma. Minor hyperechoic ill-defined regional fat is also present suggestive for associated reactive surrounding fat.

Outcome

The patient was lost to follow-up.

Clinical Differential Diagnosis

Metastatic disease associated with the mast cell tumors, pancreatitis, inflammatory bowel disease (not controlled with administration of Depo-medrol injections), cholangitis/cholangiohepatitis (not controlled with administration of Depo-medrol injections), other forms of neoplasia (lymphoma, adenocarcinoma, leiomyoma and leiomyosarcoma).