Calvarial hyperostosis presenting as unilateral exophthalmos in a female English Springer Spaniel

Abstract

A 4-month-old intact female English Springer Spaniel presented to the University of Georgia Veterinary Teaching Hospital for evaluation of unilateral, progressive exophthalmos oculus sinister (OS) of 2 weeks' duration. Complete ophthalmic examination revealed moderate OS exophthalmos and lateral globe deviation. No other abnormalities were noted on physical or ophthalmic examination, ocular ultrasound, complete bloodwork, or thoracic radiography. Skull computed tomography (CT) revealed a large, focal, smoothly irregular, cavitated, expansile bony lesion involving the left caudal maxillary and left frontal bones. Biopsies, obtained through a frontal sinusotomy approach to preserve the left globe integrity, demonstrated normal reactive trabecular bone with locally extensive fibrosis. Calvarial hyperostosis was diagnosed based upon appearance on imaging, lesion unilaterality, absence of mandibular involvement, and histopathology. Six months after initial presentation, skull CT was repeated and marked reduction in the degree of frontal bone thickening was demonstrated with complete resolution of cavitations. There was marked clinical improvement with mild, nonpainful exophthalmos, and lateral globe deviation OS on ophthalmic examination. Eleven months after initial presentation, there was complete resolution of the frontal bone lesion with mild thickening of the left calvarial bones on repeat skull CT. There was no exophthalmos or globe deviation present on clinical ophthalmic examination. The proliferative osteopathic lesion was self-resolving with resolution of the exophthalmos and has not recurred to date. To the authors' knowledge, this is the first report of calvarial hyperostosis in a previously unreported breed presenting as unilateral exophthalmos.

Craniomandibular osteopathy in a golden jackal (Canis aureus)

“…Calvarial hyperostosis syndrome (CHS), radiographically and in CT images, shows a bone reaction of the calvarium similar in appearance to CMO. However, the findings in CHS are usually focal and unilateral and the mandible is not involved 27 28. New bone formation characterised by a mosaic pattern of new woven bone and ‘islands’ of fibrous tissue in the endosteum, periosteum and the mandible trabecular bone, and in the distal section of the hindlimb in the form of irregular woven bone trabeculae, were noted histopathologically, as has been previously reported 13 16 18 20.…”

Imaging Diagnosis—magnetic Resonance Imaging Features of Craniomandibular Osteopathy in an Airedale Terrier

“…Unlike craniomandibular osteopathy, calvarial hyperostosis syndrome does not affect the mandible. It has only been described in bullmastiffs and one English Springer Spaniel …”

Management of Orbital Diseases

“…If tru-cut biopsy is not practical, a biopsy can be performed via exenteration or lateral orbitotomy. 3,28 If neoplasia B A Fig. 6.…”

“…This disease is thought to be rare and self-limiting. 28 Vascular anomalies of the orbit are uncommon and may be congenital or associated with trauma. 48,49 Nonpainful, intermittent exophthalmos in a young dog is the most common presentation.…”