Cross‐Sectional Imaging Useful in Melorheostosis

Abstract

Melorheostosis is a rare disease of bone overgrowth that is primarily diagnosed based on imaging studies. Recently, the association of different radiological patterns of the disease with distinct genetic cause was reported. Several case reports have described the radiological findings in patients with melorheostosis. However, the added value of cross-sectional imaging with CT and MRI beyond X-rays has not been investigated. The aim of the current study was to investigate this existing gap in knowledge. Forty patients with melorheostosis seen at the National Institute of Health Clinical Center were included in the study, and all their imaging studies were analyzed. The sequence of interpretation was X-ray followed by CT and then MRI. CT images were extracted from whole-body 18Fsodium fluoride positron emission tomography/CT studies. The information from CT reclassified the initial X-rays based radiological pattern in 13 patients. Additionally, CT comprehensively identified joint involvement and disease extent. In 76% of patients (n = 29) who underwent MRI, additional findings were noted, ranging from soft tissue edema to identification of soft tissue masses and incidental findings. MRI did not provide additional information on skeletal lesions beyond CT scans. However, it revealed the extension of soft tissue ossification into ischiofemoral space in four patients who complained of deep gluteal pain consistent with ischiofemoral impingement syndrome. In addition, MRI revealed soft tissue edema in 20 patients, 9 of whom had bone marrow edema and periosteal edema in the tibias consistent with shin splints. These findings suggest that select patients with melorheostosis should be evaluated with both CT and MRI, particularly patients in whom the distribution of pain does not correlate with the anatomic location of the disease in plain radiographs.

Melorheostosis (Leri’s Disease): A Review

“…Recent findings suggest somatic SMAD3 mutations can spur melorheostosis by enhancing the TGF-β/SMAD pathway. Various pathogenic factors, including developmental, ischemic, telangiectatic, hypervascularity, and infection, are associated with melorheostosis, often co-occurring with OPK or LEMD3 mutations [ 4 , 7 ]. The underlying pathophysiology of MAP2K1-positive melorheostosis might be explained by a gradual deterioration of bone microarchitecture, which subsequently triggers a periosteal reaction akin to osteomyelitis or trauma, ultimately leading to overall cortical outgrowth [ 8 ].…”

“…Subsequently, an incisional biopsy was conducted using a specific method in the affected region, with histopathological analysis confirming a diagnosis of melorheostosis. Moreover, the findings were supplemented by immunohistochemical assessments following the conventional histopathological examination [ 7 ]. The typical radiographic appearance of melorheostosis features an irregular hyperostosis that affects the outer cortical bone.…”