Page 109 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

84 CHAPTER 1

VetBooks.ir 1.144 1.145

Fig. 1.144 Intraoperative view of a large rounded Fig. 1.145 Dorsoproximal/palmarodistal oblique
keratoma immediately underneath the dorsal radiographic view of the foot of a horse with a
hoof wall (window resection). (Photo courtesy keratoma at the toe of the distal phalanx. Note the
John Peroni) defect in the hoof wall immediately dorsal to the bony
lesion. (Photo courtesy Graham Munroe)

Differential diagnosis the use of advanced diagnostic imaging, explora-
Other rare hoof tumours; chronic hoof wounds; tion of the capsule may be warranted. A definitive
abscess. diagnosis requires a biopsy and histopathological
evaluation.
Diagnosis
Most horses with a keratoma present for a lameness Management
evaluation. A keratoma may be suspected if the Keratomas that are not causing clinical signs may be
lameness is associated with: a distorted hoof cap- left untreated but monitored. The majority of cases
sule and infection; a relatively well- circumscribed that are brought to the clinician’s attention are caus-
round or oval mass of horn is visible on the ground ing signs and surgical excision (Fig. 1.146) is rec-
surface of the foot, either in the white line of the ommended. The tumours are excised through the
distal wall or in the sole; or when a dorsoproximal/ sole or a partial hoof wall resection, which can be
palmarodistal oblique radiograph shows a well- performed in the standing horse with sedation, peri-
demarcated circular or oval area of lysis in the neural analgesia and a tourniquet, or under general
solar margin/parietal surface of the distal pha- anaesthesia. The foot is bandaged, and the defect
lanx (Fig. 1.145). In horses in which a tumour is allowed to heal by secondary intention. Perioperative
suspected but cannot be identified on the surface antibiotics are advisable and may be continued if in
of the hoof capsule, imaging with CT or MRI is the course of excising the tumour, the dermis has
effective at identifying the mass as well as planning been disrupted as evidenced by haemorrhage into
a surgical approach if needed. If expense precludes the resected area.