Osteoid Osteoma in the Fourth Metatarsal: A Previously Undescribed Cause of Forefoot Pain

Abstract

We present the case of a 26 year old man who reported persistent pain in his left foot. He had been troubled by this pain for six years but despite previous consultation and investigation the cause of his symptoms had remained elusive. A magnetic resonance imaging (MRI) scan was performed which hinted at a small area of oedema in the head of the fourth metatarsal. Based on these findings, and working in close conjunction with our specialist radiology colleagues, a CT scan with finer slices was able to identify a 3 mm diameter lucency with a sclerotic central nidus. Following this challenging diagnosis, the preferred management option was an open resection of the lesion, due to its small size and superficial position. The macro and microscopic appearances of the excised lesion supported the diagnosis of osteoid osteoma, as did the complete resolution of the patient's symptoms following removal of the offending lesion. We believe this to be the first case of an isolated osteoid osteoma in the fourth metatarsal ever described in the orthopaedic literature. It highlights the importance of pursuing a diagnosis with the aid of multiple imaging modalities and MRI has again proved its use in the resolution of orthopaedic clinical conundrums.