Suture exostosis with concurrent nasal septum chondrosarcoma in a horse

Abstract

A 15-year-old Hanoverian mare presented with a 10-day history of facial swelling in the right maxillary and frontal regions, left epiphora and intermittent right epistaxis. Radiographs revealed suture exostosis of both nasofrontal sutures and a deviated and thickened nasal septum. Computed tomography (CT) of the skull revealed exostosis of the nasolacrimal sutures and ducts bilaterally of both nasofrontal sutures and of the right zygomatocomaxillary and lacrimomaxillary sutures. The mid-to-caudal aspect of the nasal septum was thickened and had multiple well demarcated hypoattenuated regions within the septum. Histological examination of biopsies taken from the right nasofrontal suture and the nasal septal mass revealed suture exostosis and nasal septum chondrosarcoma. The horse was treated with rest and anti-inflammatories. The facial swelling and left epiphora were improved at 7 months telephone follow-up. This report is the first to describe a nasal septum chondrosarcoma in a horse. Additionally, we suggest that the suture exostosis may have developed due to an alteration of the biomechanics of the skull sutures secondary to the septal tumour.

Trauma-induced exostosis of multiple suture lines causing partial bilateral nasolacrimal duct obstruction in a 7-year-old Thoroughbred mare

“…Clinical signs of suture line exostosis of the nasolacrimal, maxillolacrimal and frontolacrimal suture lines commonly include bilateral diffuse swellings situated rostrally to the medial canthus of the eye with or without accompanying epiphora (Carslake 2009; Dixon 1991; Klein et al 2014; Manso-Diaz & Taeymans 2012; Tremaine & Dixon 2001a). These swellings have consistently been reported as non-painful (Bonilla et al 2015; Carslake 2009; Klein et al 2014; Manso-Diaz & Taeymans 2012), which made the severely painful swellings in this case unusual. The severity of the pain evident in this case made us consider the possibility of fractures of the facial bones being present.…”

“…It has been shown in other species that masticatory forces could contribute to the development or persistence of suture line exostosis, with large tensile and compressive forces demonstrated across suture lines during mastication in miniature swine (Rafferty & Herring 1999). The role of masticatory forces in the development of suture line exostosis in horses has subsequently been suggested (Bonilla et al 2015; Carslake 2009; Dixon 2014). Inflammation of the nasofrontal and nasolacrimal suture lines have also been reported following frontal sinus trephination or sinonasal surgery (Manso-Diaz & Taeymans 2012; Tremaine & Dixon 2001a; Woodford & Lane 2006) and in conjunction with additional pathology such as a nasal septum chondrosarcoma (Bonilla et al 2015).…”

“…Craniofacial sutures are fibrous joints present in the skull and the nasofrontoal, nasolacrimal, nasomaxillary and frontolacrimal especially are of clinical importance (Figures 1 and 2). These suture lines are the primary sites of equine craniofacial bone growth in the horse and fuse in the first few months of life, becoming ossified between 3 months and 5 years of age (Bonilla, Wilson & Sangschi 2015; Butler et al 2009). These suture lines allow small movements before they close, which absorb mechanical stress, distribute masticatory forces, allow passage through the birth canal and contribute to the elastic properties of the skull (Dixon 2014; Rafferty & Herring 1999; Rafferty, Herring & Marshall 2003; Rice 2008).…”

“…Suture exostoses are normally areas of non-painful bone proliferation that usually regress with time (Dixon 1991; Gibbs & Lane 1987; Klein et al 2014; Tremaine & Dixon 2001a). As the nasolacrimal ducts are imbedded in the ventral aspect of the nasal and frontal bones, nasofrontal suture line exostoses with local inflammation and bone proliferation can cause partial or complete obstruction of the nasolacrimal ducts with secondary epiphora (Bonilla et al 2015; Carslake 2009; Klein et al 2014; Manso-Diaz & Taeymans 2012).…”

Equine sinonasal tumours: Does reporting of single cases and case series still advance the neglected field of equine clinical oncology?

“…The case report by Bonilla et al . () describes a 15‐year‐old Hanoverian mare that presented with a 10‐day history of maxillary and frontal area swellings and intermittent epistaxis. Computed tomography of the skull confirmed periostitis of multiple facial bone sutures, including of the nasofrontal, nasolacrimal, zygomaticomaxillary and lacrimomaxillary sutures, in addition to thickening of the nasal septum that contained hypoattenuated regions.…”