Bone scintigraphy elucidates different metabolic stages of melorheostosis

Abstract

Melorheostosis is a rare benign non-hereditary sclerosing dysplasia involving the bone, often in a sclerotomal distribution. we report the case of a 27 years old lady with painful swelling of the left hand and forearm lasting for almost 15 years. The patient experienced aggravation of symptoms and limitation of motion during the past two months. Radiographic assessment revealed hyperostosis involving the left 3^rd and 4^th metacarpal bones and corresponding digits as well as the left ulna and distal humerus, with no soft tissue ossification. Angiographic and blood pool images of bone scintigraphy showed increased activity of mid-metacarpal region, corresponding to the sclerotom C-8. Delayed static views showed increased radiotracer uptake of the left 4^th metacarpal bone and the corresponding digit as well as the left ulna and humerus, but no abnormal osteoblastic activity of the 3^rd left metacarpal and digit. Histopathologic assessment confirmed the diagnosis of Melorheostosis. The case confirms that even in the same sclerotomal distribution, the multiple foci of involvement can present in different metabolic stages. In fact, the disease does not progress uniformly and different lesions can be seen in dissimilar stages of activity. Hence, metabolic imaging can be important to unmask which of the radiographically detected bony lesions are metabolically active and have the potential to be the source of current patient's symptoms and which of them are old, metabolically inactive and silent lesions, which are not clinically relevant to the patient's complaints.