A rare case of intraosseous lipoma of distal tibia – A case report and review of literature

Abstract

Introduction: Intraosseous lipoma is a very rare neoplasm accounting for < 0.1 % of primary bone tumors. Pain is the leading symptom in majority of the reported cases but it can be asymptomatic. There is slight male predominance in occurrence of this lesion. The plain radiological findings are not specific and requires differential diagnosis. The lesion is mostly diagnosed by histopathological examination. Case report: A 31-year-old male presented with localized pain around the medial aspect of right ankle joint for one week. Examination revealed mild tenderness over the distal part of the right tibia over the medial aspect. Plain radiograph of the right leg showed well-defined expansile osteolytic lesion with sclerotic rim and calcified matrix at metaphysis of distal tibia. MRI showed enhancing T1-weighted hypo intense and T2-weighted hyperintense lesion. For this case, radiological impression was giant cell tumor with differential diagnosis of aneurysmal bone cyst and fibrous dysplasia. However, the histopathological examination showed intraosseous lipoma, consistent with stage II of Milgram’s classification. Conclusions: Although the diagnosis of intraosseous lipoma can be very challenging due to its rarity and indistinct plain radiograph findings, combination of computed tomography or magnetic resonance imaging may be useful by being able to show the presence of fat within the lesion. However, the clinicians, surgeons and radiologist should be familiar and be aware of these findings to be able to come to a correct diagnosis since not all cases need surgery and can be managed conservatively.