Melorheostosis: Clinical Experience of 23 Cases

Presentation Number: MON 330
Date of Presentation: April 3rd, 2017

Smita Jha*, Georgios Papadakis, Lauren Kim, Ashkan Malayeri, Edward W. Cowen, Tanya Lehky, Lauren Flynn, Katharine Alter, Eileen Lange, James Katz, Joan Marini, Richard Siegel and Timothy Bhattacharyya
National Institutes of Health

Abstract

Background:

Melorheostosis is a rare sclerotic disease of the long bones diagnosed on radiographs by its characteristic “flowing candle wax” appearance. There are no prospective studies detailing the disease phenotype.

Methods:

We prospectively recruited 23 adult patients with a radiographic diagnosis of melorheostosis and corresponding increased uptake on 18F-NaF PET/CT. Patients underwent standardized examination and testing. Whole body skeletal burden of the disease was assessed by quantifying the 18F-NaF activity.

Results:

Our cohort comprised of 18 females (78%) and 5 males with a mean age of 45 ± 12 years. Fourteen patients (61%) had melorheostosis in the lower extremities. The mean age of onset of symptoms was 18 ± 13 years. All patients reported pain and limitation of physical function. Vascular changes in the skin overlying the affected bone were identified in 7 patients (30%). Thirteen patients (57%) reported numbness or tingling in the affected limb, of which all but 2 were confirmed on exam. In addition, 7 patients without subjective sensory symptoms were found to have altered sensation corresponding to the disease site. Limitation of range of motion was noted in 12 patients (52%) with muscle atrophy in 7. Electrophysiological testing confirmed the sensory findings on exam in 7 patients, and ultrasound study showed encapsulated or displaced nerves in 3 patients.

The classic “candle-wax” radiographic pattern was seen in 16 patients (70%). Disease distribution conformed to the sclerotomal map in only 12 patients (52%). Extra-osseous mineralization was found in 9 patients (39%), 5 of which were para-articular. The skeletal burden of the disease is significantly higher among patients with soft tissue mineralization (p-value = 0.001), as is duration of disease, though it is not statistically significant. The skeletal disease burden did not show a significant correlation with disease duration. Patients with a higher skeletal burden tended to have a higher serum NTX (r=0.6; p=0.002) and P1NP (r=0.4, p = 0.08).

Conclusions:

This is the first and largest prospective study of melorheostosis, a rare and poorly understood condition. Elevated bone formation and resorption markers, as well as high focal uptake on scan suggest lesions may have high turnover. A high prevalence of sensory findings indicates that secondary effects on nerves plays a role in patient symptoms. Contrary to published literature, the distribution of melorheostosis did not conform to the distribution of sclerotomes in nearly 50 percent of our cohort. Lesions in melorheostosis can be effectively targeted and monitored using whole-body PET/CT imaging with 18F-NaF, since all disease-related abnormalities demonstrated intensely elevated 18F-NaF activity. Further studies are needed to better understand the disease distribution and predisposition to extra-osseous mineralization and associated skin lesions.

 

Nothing to Disclose: SJ, GP, LK, AM, EWC, TL, LF, KA, EL, JK, JM, RS, TB