Case Report: Diagnosis of multiple juvenile angiomatosis in a newborn calf.

Juvenile angiomatosis is a rare vascular anomaly that has never been examined by ultrasonography and computed tomography in bovine practice. A four-days-old, Japanese-Black, male calf presented with multiple swollen skin lesions aligned along the dorsoventral axis of the left thoracic wall. Ultrasonography showed homogeneous echogenic masses between the subcutaneous and muscular structures. Anatomical connection between the mass lesions and neighboring structures was ultrasonographically unclear based on differences in echogenicity and the hyperechoic membranous structures between them. Doppler ultrasonography revealed poor vascularity, which is a common feature of mass lesions. Computed tomography (CT) revealed seven masses in the left thoracic wall. Five of the seven masses were isolated from each other, although there was an anatomical connection between two masses formed at the level of the spinous processes of the ninth to thirteenth thoracic vertebrae. The largest mass was located in the most ventral region of the thoracic wall, corresponding to deformities of the sixth to tenth ribs, which showed severe inward rolling into the thoracic cavity on three-dimensional CT. Core-needle biopsy allowed histopathological observation of the predominant intra-mass configuration of vessel-like structures. Histopathological examination of tissue samples collected at necropsy revealed that multiple immature vessel-like structures were present within the mass lesions that commonly involved the skeletal muscles. Positive immunostaining was found for von Willebrand factor in the endothelial cells, and for alpha-smooth muscle actin in the cells comprising the walls. These findings could support a diagnosis of bovine juvenile angiomatosis. Both ultrasonography and CT provided no definitive evidence to support the macroscopic and histopathological findings showing invasion of the masses into neighboring muscular structures. A combination of diagnostic techniques, including ultrasonography, CT, and core-needle biopsy, helped provide complementary information that supported the histopathological and immunohistochemical diagnosis of this disease.