Ultrasonographic Features of Canine Abdominal Malignant Histiocytosis

Abstract

Ultrasonographic features of canine abdominal malignant histiocytosis (MH) of 16 dogs are reported. The most common finding was the presence of hypoechoic nodules in the spleen, some of which caused distortion of the splenic margin. The liver was the second-most commonly affected organ. Hepatic ultrasonographic features were highly variable, including hypoechoic, hyperechoic, or mixed echogenic lesions. Other common ultrasonographic abnormalities included hypoechoic nodules in the kidneys and mesenteric and medial iliac lymphadenopathy. The results of this study suggest that the ultrasonographic appearance of canine abdominal MH is nonspecific, and definitive diagnosis requires cytologic or histologic examination.

Liver

“…Nonmalignant vascular patterns consist of a more orderly arrangement of branching specificity of 95% in a recent report. 104,105 Because mesenteric and medial iliac lymph nodes are often involved with malignant histiocytosis, lymphosarcoma is a differential diagnosis for this appearance. 103 Malignant histiocytosis can affect multiple organs, including the liver.…”

Spleen

“…If the hyperplastic nodule becomes congested or necrotic, complex lesions may Text continued on p. 417 Splenic abscesses may result from bacterial septicemia, peritonitis, or diseases that produce vascular compromise, necrosis, and secondary bacterial infection. 46 The appearance is nonspecific, and an ultrasound guided aspirate is required for diagnosis. Multiple, hyperechoic focal lesions (black arrows) were identified in the spleen of a dog with bacterial septicemia.…”

“…A, Focal splenic abscess. 46 Thoracic abnormalities may include pulmonary nodules or consolidation, mediastinal masses, or pleural effusion. The lesions did not shadow but exhibited weak edge shadowing (white arrows) typical of a curved structure in which a sound velocity change has occurred.…”

“…46 Eleven-year-old spayed female mixed breed dog with a history of a grade II mast cell tumor incompletely excised from her axilla and an enlarged axillary lymph node. The spleen was judged to be normal but fine-needle aspiration was performed because of the clinical presentation.…”

Gastrointestinal Tract

“…Carcinomas often cause annular thickening with obstruction of the colon similar to that in the small bowel. 131 Mast cell tumors have been described at the ileocolic junction or colon in cats. 44,45 Other tumors such as leiomyosarcoma or leiomyoma of the cecum or colon also occur, but have lower incidence.…”