SONOGRAPHIC FEATURES OF HISTIOCYTIC NEOPLASMS IN THE CANINE ABDOMEN

The purpose of this retrospective study was to describe the ultrasonographic features of malignant histiocytosis (MH), malignant fibrous histiocytoma, and histiocytic sarcoma in abdominal organs of dogs. The medical records of 18 dogs that had undergone abdominal sonography and had a histopathologic diagnosis of abdominal MH, malignant fibrous histiocytoma, and histiocytic sarcoma were reviewed. The organ most commonly affected was the spleen. MH was the most common followed by histiocytic sarcoma and malignant fibrous histiocytoma. In the spleen there were often multiple hypoechoic nodules with well-defined borders. In one dog, without focal lesions, the spleen was enlarged and hypoechoic. The liver was the second most commonly affected organ. MH was most common followed by histiocytic sarcomas and malignant fibrous histiocytoma. The most common sonographic feature in the liver was the presence of multiple hypoechoic nodules with well-defined borders. One dog without hepatic nodules had a liver that was ultrasonographically enlarged and hypoechoic. MH in the abdominal lymph nodes resulted in hypoechoic lymphadenopathy. Malignant fibrous histiocytoma was the only neoplastic type in the kidneys appearing as a single heteroechoic renal mass with well-defined borders. MH was observed in the stomach of one dog. Sonographically there was a single well circumscribed hypoechoic mass with well-defined borders and abnormal stomach layers. In this study it was not possible to differentiate between MH, malignant fibrous histiocytoma, and histiocytic sarcoma using sonography.