Osteochondroma of the First Phalanx in Tbourida Horses

Abstract

This study aimed at describing anatomo-histopathological and imaging features, using computed tomography and magnetic resonance imaging on six ex vivo forelimbs of Tbourida horses, that presented a particular bone exostosis on the dorsal and proximal part of the first phalanx, diagnosed by X-ray. Gross anatomy of the bone exostosis revealed an irregular surface with poly-lobulated tissue masses showing a cauliflower shape. The diameter/depth varied from 0.5 to 5.1 cm with a mean of 3.9 ± 0.9 cm. The capsule of the metacarpophalangeal joint was hypertrophic and showed many invaginations in the inner part, in contact with the bone exostosis. Computed tomography revealed cortical and medullary continuity of the bone exostosis, with the underlying bone, and remodeling of the cortical surface of the dorsal and proximal part of the first phalanx. Magnetic resonance imaging showed an increased signal intensity of the bone exostosis on the T1- and T2*-weighted gradient fast echo. Histological examination of the bone exostosis revealed a cap of hyaline cartilage, including large foci of endochondral ossification with a base of cancellous bone surrounding marrow spaces, which confirmed the diagnosis of osteochondroma. The capsule of the metacarpophalangeal joint showed a large amount of recently formed connective tissue fibers in its inner part, interspersed with mature connective tissue. The hyperextension of the metacarpophalangeal joint during a Tbourida show, which occurs on a hard ground surface, and the use of hobbles in horse stabling are most likely responsible for the outgrowth of an osteochondroma of different shapes and sizes, and fracture complications in some cases.

Osteoarticular radiographic findings of the distal forelimbs in Tbourida Horses

“…Histological examination of the OBE revealed a cap of hyaline cartilage, including large foci of endochondral ossification with a base of cancellous bone surrounding marrow spaces, which confirmed the diagnosis of osteochondroma lesion. Such osteochandroma lesions are rare in horses [32].…”

“…A particular radiographic finding showing a bony overgrowth that looked like an exostosis on the dorsal and proximal part of the P1 was observed in 19,6% of the examined horses. In a recent study, we have diagnosed this lesion as an osteochondroma of the P1 [32]. Indeed, using different approaches (Computed tomography, Magnetic resonance imaging, histology analysis) on six ex vivo forelimbs of Tbourida horses that presented a particular OBE on the dorsal and proximal part of the P1 diagnosed previously by X-ray, computed tomography (CT) showed bone remodeling on the dorsal and proximal surface of the P1, with the presence of several bone fragments at this level.…”

Computed tomographic (CT) arthrogram contributes to the diagnosis of an osteochondroma of the distal calcaneus in a horse

“…These findings increase the index of suspicion of an osteochondroma; however, histopathology is necessary for a definitive diagnosis. There have been reports of advanced imaging techniques such as scintigraphy, CT and MRI, being used to aid diagnosis of osteochondroma (Secombe and Anderson 2000;Dixon and Anderson 2019;Seghrouchni et al 2019). Non-contrast CT and MRI were used to aid the diagnosis of an osteochondroma on the proximal phalanx (Seghrouchni et al 2019).…”

“…There have been reports of advanced imaging techniques such as scintigraphy, CT and MRI, being used to aid diagnosis of osteochondroma (Secombe and Anderson 2000;Dixon and Anderson 2019;Seghrouchni et al 2019). Non-contrast CT and MRI were used to aid the diagnosis of an osteochondroma on the proximal phalanx (Seghrouchni et al 2019). Sechrouchni et al (2019) described how CT provided essential cross-sectional information about the cortical and medullary continuity of the osteochondroma with the underlying bone.…”

“…Non‐contrast CT and MRI were used to aid the diagnosis of an osteochondroma on the proximal phalanx (Seghrouchni et al . 2019). Sechrouchni et al .…”