Sino-orbital osteoma: a clinicopathologic study of 45 surgically treated cases with emphasis on tumors with osteoblastoma-like features.
BACKGROUND
Osteomas are limited almost exclusively to craniofacial and jaw bones. Histologically, they can be divided into ivory, mature, or mixed types. Osteomas may have osteoblastoma-like areas and distinguishing it from true osteoblastoma can be challenging. Some believe osteomas with osteoblastoma-like features behave more aggressively.


OBJECTIVE
To perform a clinicopathologic comparison of sino-orbital osteomas both with and without osteoblastoma-like features.


METHODS
We studied 45 surgically excised sino-orbital osteomas. Tumors were categorized as ivory, mature, or mixed type and presence of osteoblastoma-like areas and Paget-like bone were noted. Clinical features of those with and without osteoblastoma-like areas were compared.


RESULTS
Men outnumbered women (3:2); median age was 37 years. Frontal sinus was the most common location (62%) followed by ethmoid and maxillary sinuses. Twelve tumors (27%) involved the orbit, 2 primarily and 10 secondarily. All cases were symptomatic with headache, sinusitis, visual changes, pain, and proptosis being most common. Seventeen tumors (38%) had osteoblastoma-like areas. Extension into an adjacent sinus/anatomic compartment was more common in osteoblastoma-like tumors (47% versus 29%), including more frequent orbital involvement (41% versus 13%). Visual changes were more frequent in the osteoblastoma-like group. Distribution of histologic subtypes and Paget-like bone were similar between the 2 groups. Osteomas with osteoblastoma-like features were more often incompletely excised (25% versus 14%). However, clinical recurrence was less common (8% versus 27%).


CONCLUSIONS
Osteoblastoma-like features are common in sino-orbital osteomas, but it does not correlate with more adverse clinical features or worse outcome. Osteoblastoma-like areas appear to represent active remodeling within an osteoma rather than defining a distinct clinicopathologic entity. Distinguishing it from osteoblastoma may require careful histologic evaluation and radiographic correlation.
Department of Pathology, University of Michigan Health System, Ann Arbor, MI 48109-0054, USA. jonamch@umich.edu
Jonathan B
JB
McHugh
Suresh K
SK
Mukherji
David R
DR
Lucas
D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local; D009378:Neoplasms, Multiple Primary; D009918:Orbital Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery; D018215:Osteoblastoma / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery; D010016:Osteoma / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery; D010255:Paranasal Sinus Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery; D011859:Radiography; D055815:Young Adult