Report of 3 cases of pediatric sinus osteomas with osteoblastoma-like features

Osteomas are one of the most common benign fibro-osseous lesions affecting the sinonasal tract. Rarely osteomas have osteoblastoma-like areas histologically, which are often misdiagnosed radiologically and pathologically as osteoblastomas. We report the CT and MR imaging findings of 3 cases of osteoma with osteoblastomas-like features in pediatric patients, 1 initially diagnosed as an osteoblastoma. Only 5 case reports of osteoma with osteoblastoma-like features within the paranasal sinuses have been reported in the English literature to date using the PubMed search engine, none of which include pediatric patients. We review the typical zonal imaging characteristics of this rare presentation of osteoma and propose a distinct "sclerotic cap" sign to aide radiologists in differentiating osteomas with osteoblastoma-like features from the more common benign fibro-osseous lesions. Additionally, we address some radiologic-pathologic discrepancies in diagnosis between osteoblastoma and osteoma with osteoblatoma-like features.