Ultrasonography and fine needle aspirate cytology of the mesenteric lymph node in normal domestic ferrets (Mustela putorius furo).

The large mesenteric lymph node of 28 normal ferrets was imaged with ultrasound. The large node, located in the mid-abdomen at the root of the mesentery, was round to ovoid and uniformly hyperechoic. Mean ultrasonographic dimensions of the lymph node were 12.6 +/- 2.6 mm by 7.6 +/- 2.0 mm. Fine needle aspirates of 20 lymph nodes were obtained either using ultrasound guided free-hand techniques or at necropsy. The cytological descriptions were compared to histological descriptions of 13 lymph node core biopsies obtained during laparotomy or necropsy as well as 10 peripheral blood smear differentials. The large mesenteric lymph node of ferrets could be easily imaged and measured by ultrasound and evaluated by fine needle aspirate cytology. Normal lymph node cytology may include an eosinophilic infiltrate.