Small Animal Radiology and Ultrasound: A Diagnostic Atlas and Text

Chapter Two The Thorax 69
Fig. 2-43 A 10-year-old spayed German Shepherd dog with mammary
tumors. There is a large soft tissue– and mineral-density lesion
located in the area of the caudal ventral right thorax. A, This mass overlies
the right caudal lung lobe (arrows) on the ventrodorsal radiograph
and mimics an intrapulmonary lesion. B, On the lateral radiograph, its
position external to the thorax is identified clearly. Note that the cranial,
dorsal, and ventral margins of this mass are outlined distinctly, while
the caudal margin is less distinct. This is due to air outlining the margins
of the mass, with its attachment blending caudally with the thoracic
wall density. External thoracic masses may overlie the lung and
mimic intrapulmonary disease. Usually their position can be identified
accurately on one of the two radiographic projections. Diagnosis:
Mammary gland mass on the right ventral caudal thoracic wall. There
is no evidence of pulmonary metastasis.
A
B
which the lesion blends into similarly echogenic tissue, the delineation may not be so clear.
The question of whether a mass is solid or cystic (fluid filled) will be answered by the ultrasonographic
examination. True cysts have few or no internal echoes, have a distinct wall,
and show evidence of through transmission (far enhancement). Solid structures have internal
echoes, less sharply defined walls, and no through transmission. Hematomas and