Types of orbital osteoma - A descriptive analysis.

AIMS: This study describes different types of orbital osteoma based on clinical per-operative morphology and radiological findings to facilitate communication between ophthalmologists and surgical management for a better patient outcome.

MATERIALS AND METHODS: The study was conducted in the Orbit and Oculoplastics Department of Al-Shifa Trust Eye Hospital, Rawalpindi, Pakistan, from July 1, 2001 to June 30, 2014. A retrospective analysis of 520 diagnosed orbital tumours who presented to us was carried out and the prevalence of orbital osteoma was determined. The sampling technique was non-randomized sampling. Based on the clinical morphology observed during surgical intervention as well as the radiological findings of the orbital osteoma, a simple yet useful description of orbital osteoma was introduced.

RESULTS: The retrospective analysis of 520 diagnosed orbital tumours revealed a prevalence of 2.3% (n = 12) of orbital osteoma. Based on our observation of the 12 (n = 12) cases of orbital osteoma, we have classified orbital osteoma into a combination of seven types: "sessile" or broad-based osteoma; "pedunculated" or mushroom osteoma with a thin cylindrical stalk of origin; "dumb-bell"-shaped osteoma with the simultaneous presence in orbital and adjoining sinus/nasal cavity; "wrapped" osteoma, covered by a thin cartilaginous layer; "naked" osteoma, without any such covering; "homogenous" or uniformly dense osteoma; and "heterogeneous", soft-dense osteoma with varying areas of density.

CONCLUSION: This study attempts to introduce a simple description of different types of orbital osteoma based on clinical per-operative morphology and radiological findings for the first time to facilitate the surgical removal of orbital osteoma.