Page 193 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

168 CHAPTER 1

VetBooks.ir ENOSTOSIS-LIKE LESIONS Clinical presentation
Horses are usually presented for lameness evaluation.
Definition/overview
Enostosis-like lesions have been identified in the Differential diagnosis
radius as well as other long bones (e.g. femur/tibia). Stress fractures.

Aetiology/pathophysiology Diagnosis
Enostosis-like lesions describe single or multifocal Diagnosis is often made scintigraphically where
areas of increased bone density often seen around increased radiopharmaceutical uptake is present in
nutrient foramen in long bones. They are uncom- the diaphysis of one or more bones (Fig. 1.319).
mon but if found are most commonly seen in the Radiographically, lesions are described as oval or
hindlimb. They may be incidental findings but have indistinct areas of increased radiopacity within the
been described as a cause of lameness, particularly if medulla and are often associated with nutrient fora-
involving the femur or humerus. men (Figs. 1.320, 1.321). The clinical relevance of

1.319

Figs. 1.319–1.321 This 9-year-
1.320 1.321
old Warmblood dressage horse
presented with lameness of the
left fore- and left hind legs. The
lameness was not localised in either
leg by diagnostic regional or intra-
articular analgesia techniques, but
a bone scan revealed focal increased
areas of radiopharmaceutical uptake
in the mid-radius (1.319) and mid-
tibia. Lateromedial (1.320) and
craniocaudal (1.321) radiographs of
the radius revealed a roughly oval-
shaped area of increased radiopacity
within the medulla – an enostosis-like
lesion. The same type of lesion was
present in the tibia. (Photos courtesy
Graham Munroe)