Congenital infiltrative lipomas and retroperitoneal perirenal lipomas in a calf.

BACKGROUND Congenital lipocytic tumours have rarely been reported in cattle. Lipomas are benign tumours, but infiltrative lipomas have significant health implications due to their aggressive infiltrative growth pattern. CASE PRESENTATION A calf was born with skeletal malformations and soft tissue proliferations, primarily on the external thoracic wall. The calf was euthanized for welfare reasons and submitted for post mortem examination. Necropsy, histopathology and post mortem computed tomography scanning revealed two types of lipocytic tumours. Widespread infiltrative lipomas were present in the muscles and connective tissues along the vertebral column and diffusely invaded the external soft tissues of the right thoracic wall. The neoplastic lipocytes had invaded intervertebral spaces thus causing congenital vertebral malformations, and further invaded the vertebral canal and the bone marrow of coccygeal vertebrae. Periosteal localization of the tumour was associated with costal hyperostosis. Two large retroperitoneal lipomas enclosed the kidneys and occupied much of the abdominal space. CONCLUSION The development of congenital bone malformation in this calf illustrates the severe consequences of the infiltrative and aggressive growth of infiltrative lipomas during foetal development. The congenital retroperitoneal lipomas occupied a large part of abdominal cavity, but did not invade the adjacent tissues. Due to their large size, perirenal lipomas should be considered in calves with distended abdomen, even in cases without other signs of tumours.