Blood within the bone: orbital intraosseous venous malformation.

PURPOSE: Description of clinical features, radiological characteristics, and management strategies in primary orbital intraosseous venous malformation (OIVM) with pertinent literature review.

METHODS: A retrospective analysis including clinical, radiologic, operative, and histopathological data of six cases of histopathologically proven OIVM was done. A comprehensive literature review was conducted using online databases and augmented with manual search to identify reported cases of OIVM.

RESULTS: Study data showed five females and one male in young to middle-age group, with an average age of 30 years (range: 20-48 years). Proptosis was noted in five cases (83.33%), and the duration of symptoms ranged from 6 months to 10 years. Frontal and zygomatic bones were most frequently affected and expansile bony lesion was the most common CT scan finding. Three patients underwent pre-operative embolization of feeders followed by en bloc excision of mass and surgical reconstruction (50%); one patient was managed with partial excision (16.66%) while two were regularly followed-up after incision biopsy (33.33%). Histopathology revealed vascular spaces with endothelial lining, separated by bony trabeculae in all patients. Follow-up periods ranged from 6 to 48 months and no recurrence or progression were noted.

CONCLUSIONS: OIVM is an exceptionally rare disorder with a gradually progressive benign course. Ophthalmologists need to be mindful of this entity during patient evaluation as it has propensity for large volume blood loss intra-operatively, owing to its vascular nature. Complete excision with reconstruction of resultant defect is the preferred treatment strategy and without known recurrence.