Diagnosis and treatment of biaxial keratomas in the left fore foot of a 15‐year‐old Clydesdale mare

A 15‐year‐old Clydesdale mare presented for further diagnostics and treatment of waxing and waning lameness and recurrent subsolar abscesses. Radiographs and computed tomography revealed biaxial masses extending from the hoof capsule, causing bone resorption of the distal phalanx. Surgery was performed to remove the masses and post operative care included regional limb perfusions, systemic antibiotics and therapeutic shoeing. Histopathology was consistent with the diagnosis of keratoma for each of the masses; this is the first case of confirmed biaxial keratomas. Two months after surgery the horse is sound at the walk and is expected to return to full function within the next year.     

Supracoronary approach for keratoma removal in horses: Two cases

Two competitive horses were presented for examination of chronic lameness; one associated with a hoof‐wall deformity, the other with a firm mass over the dorsal pastern region. Radiographs revealed moderately radiopaque masses associated with both deformities. The lesions were characterised ultrasonographically as noninvasive, well‐circumscribed heterogeneous masses. Computed tomographic examination of the second case revealed a well‐defined, partially mineralised, bi‐lobed mass with associated bony resorption of the underlying middle phalanx. Both patients were anaesthetised and the keratomas surgically removed via approaches 1–2 cm proximal to the coronary bands. Both horses were stall‐sound 2 days after surgery and returned successfully to an equal level of competition by 8 months. A supracoronary approach is a viable alternative to partial or complete hoof wall resection for the removal of nonsolar keratomas from the foot of a horse.     

Low‐field magnetic resonance imaging of keratomas of the hoof wall

Standing low‐field magnetic resonance imaging (MRI) was used to image the feet of 21 horses affected by keratomas. The animals had variable clinical histories including acute, chronic or recurrent lameness. Of the 21 horses, only 14 (66%) had radiological changes suggestive of keratoma. Standing low‐field MRI revealed a smoothly demarcated hoof wall lesion in all horses, with deformity of the adjacent surface of the distal phalanx in 15 cases. The signal characteristics of the keratomas varied, with most showing either hypointensity or heterogeneous mixed signal intensity in T1‐ and T2*‐weighted images and hypointensity in STIR sequences. An intermediate or high STIR signal intensity was present in the trabecular bone of the adjacent region of the distal phalanx in 5 cases. Surgical debridement was performed in 16 horses. Recurrence was common, especially in cases where the lesion was ill‐defined; the prior MRI appearance of these cases tended to be of heterogeneous signal intensity.     

Standing low-field magnetic resonance imaging as a diagnostic modality for solar keratoma in a horse

A 22-year-old Friesian gelding was presented with a history of chronic, nonresolving lameness localised to the right front foot. Radiographs showed a smoothly marginated circular lucent area with a rim of increased opacity adjacent to the solar canal of the distal phalanx. The magnetic resonance imaging (MRI) revealed a reversed V-shaped smoothly demarcated space-occupying mass causing invagination of the solar laminae towards the solar canal arch and deformity of the adjacent surface of the distal phalanx. The mass was removed surgically and submitted for histopathology, which revealed a keratoma and periosteal fibrosis. Six weeks post-surgery the horse returned to the previous work level and 8 months follow-up showed no recurrence of keratoma. This report highlights the usefulness of MRI as a diagnostic modality for solar keratoma.