What is your diagnosis? Fine-needle aspirate of an aggressive bone lesion in a dog

Abstract

A 2-year-old intact male Labrador Retriever was presented to The Ohio State University Veterinary Teaching Hospital with a history of right forelimb lameness and slight swelling around the right distal antebrachium for 1 month. Results of a CBC and serum biochemical profile were unremarkable. Radiographs of the right antebrachium, acquired by the referring veterinarian, showed an irregular ovoid rim of mineralized perisoteum around the distal right ulna (Figure 1). Accompanying this were other regions of smooth yet irregular periosteal reaction seen circumferentially on the distal ulna and radius. Osteolysis of the craniodistal cortex of the right ulna was present, and an oval radiolucent area was seen in the ulna distal to the irregular periosteal reaction and lytic region. The soft tissues surrounding the distal antebrachium were swollen. A fine-needle aspirate was collected from the cranial aspect of distal radial cortex and stained with Hema 3 (Fisher Diagnostics, Middletown, VA, USA) (Figure 2).