Recurrent intraosseous spindle myoepithelioma of the distal fibula: A clinical and radiological challenge

Abstract

A 42-year-old man with a past history of lipomas, presented with right ankle pain radiating to the hip and limited range of motion of the ankle. An initial XR was performed revealing an expansile lytic lesion in the right distal fibula. Next, an MRI was performed to confirm this expansile lytic lesion. Initial presumptive differential diagnoses included chondromyxoid fibroma, osteoblastoma, intraosseous ganglion cyst and Brodie’s abscess. However, upon bone biopsy the pathology report revealed that the lesion was smooth muscle actin (SMA) positive and an ultimate diagnosis of intraosseous spindle myoepithelioma (ISM) was made. Curettage was then performed on the initial lesion to excise the tumor. The patient since has had multiple recurrences of this lesion. The diagnosis of ISM is rare and can present with many challenges in diagnosis radiologically and clinically as this tumor can mimic many common diagnoses. Due to the paucity of literature on this topic, documentation of this case will help enhance the understanding of this rare lesion, its behavior, and possible genetic associations.