Intraosseous lipoma of the frontal bone : CT – MRI discordance

Abstract

Intraosseous lipoma is a rare, benign mesenchymal tumor that is frequently found in the appendecular skeleton, involving the calcaneus ^[1] and the metaphyses of long bones. Intraosseous lipoma of the skull is even rarer with only a handful of cases described in the literature. In course, they usually undergo varying degrees of involution with necrosis, cyst formation, and calcification. Here we report a case of a 8 year old girl, who presented with a hard bony swelling of the calvarium  on the left side for the past 3 months. A preliminary non contrast Computed  Tomography (CT) scan  was suggestive of fibrous dysplasia. However an Magnetic resonance imaging (MRI) scan revealed an expansile lesion of the frontal bone on the left side which was homogeneously hyperintense on T1 and T2 weighted images with uniform suppression on fat saturated images, which was suggestive of Milgram stage 1 intraosseous lipoma. The above mentioned CT-MRI discordance lead to subsequent biopsy of from the lesion, which confirmed our diagnosis of an intraosseous lipoma.

Key words

Intraosseous lipoma,  frontal bone,  Magnetic resonance imaging (MRI), Computed  Tomography (CT)