Progressive pseudorheumatoid dysplasia (PPRD) is a genetic, non-inflammatory arthropathy caused by recessive loss of function mutations in WISP3 (Wnt1-inducible signaling pathway protein 3; MIM 603400), encoding for a signaling protein. The disease is clinically silent at birth and in infancy. It manifests between the age of 3 and 6 years with joint pain and progressive joint stiffness. Affected children are referred to pediatric rheumatologists and orthopedic surgeons; however, signs of inflammation are absent and anti-inflammatory treatment is of little help. Bony enlargement at the interphalangeal joints progresses leading to camptodactyly. Spine involvement develops in late childhood and adolescence leading to short trunk with thoracolumbar kyphosis. Adult height is usually below the 3rd percentile. Radiographic signs are relatively mild. Platyspondyly develops in late childhood and can be the first clue to the diagnosis. Enlargement of the phalangeal metaphyses develops subtly and is usually recognizable by 10 years. The femoral heads are large and the acetabulum forms a distinct "lip" overriding the femoral head. There is a progressive narrowing of all articular spaces as articular cartilage is lost. Medical management of PPRD remains symptomatic and relies on pain medication. Hip joint replacement surgery in early adulthood is effective in reducing pain and maintaining mobility and can be recommended. Subsequent knee joint replacement is a further option. Mutation analysis of WISP3 allowed the confirmation of the diagnosis in 63 out of 64 typical cases in our series. Intronic mutations in WISP3 leading to splicing aberrations can be detected only in cDNA from fibroblasts and therefore a skin biopsy is indicated when genomic analysis fails to reveal mutations in individuals with otherwise typical signs and symptoms. In spite of the first symptoms appearing in early childhood, the diagnosis of PPRD is most often made only in the second decade and affected children often receive unnecessary anti-inflammatory and immunosuppressive treatments. Increasing awareness of PPRD appears to be essential to allow for a timely diagnosis.

There are only a few studies that address the frequency and type of spinal involvement in patients with chronic recurrent multifocal osteomyelitis (CRMO) as well as the outcome of these patients treated with pamidronate (PAM). We performed a retrospective study on patients with CRMO and analyzed clinical and pain assessments as well as regional and whole body MRI findings and compared with posttreatment findings. Of 102 children and adolescents with CRMO, 27 (26%) had involvement of the spine. Vertebral deformities were seen in 14 of these 27 patients, scoliosis or kyphosis in 6. After routine whole body MRI, 19 complained of back pain, whereas eight were asymptomatic with spinal lesions detected incidentally. A total of 72 spinal lesions were detected, thoracic vertebrae being the most commonly affected. Seven patients were treated with PAM; all of whom had vertebral deformities and ongoing back pain. Pain resolution was achieved within 3 months of PAM treatment in every case. One patient subsequently developed a pain amplification syndrome. Repeat MRI performed at a mean interval of 13 months revealed partial or complete resolution of vertebral hyperintensities in every patient. Improvement of vertebral height was seen in a total of three vertebrae in two patients. Severe side effects were not observed. In conclusion, we demonstrated that spinal involvement and associated vertebral deformities with or without kyphoscoliosis are not rare in CRMO, and PAM appears to be an effective and safe treatment for this condition. Although controlled studies are urgently needed, the use of PAM for refractory CRMO with extended spinal involvement (vertebral deformities, kyphosis, and scoliosis) should be considered, especially after failing of conventional therapy.

Purpose: The diagnosis of CRMO often involves a long patient history. We evaluated the spectrum of bone involvement in whole-body magnetic resonance imaging (WB-MRI) and assessed its potential contribution to a more rapid diagnosis. Materials and Methods: WB-MRI (1.5?T, coronal STIR sequences) in 53 children and adolescents (mean age 11 years, 4.8???15.1) with histologically (n?=?37) or clinically (n?=?16) confirmed CRMO were retrospectively reviewed by two experienced pediatric radiologists. Results: WB-MRI revealed multifocal lesions in all but one patients. Only 26 of them had presented with multifocal complaints. We detected 1???27 geographic lesions/patient (mean 9.7). 510 of 513 lesions were significantly hyperintense compared to normal bone marrow. The pelvis, lower extremities, shoulders and spine were most frequently involved. 40 patients (75?%) had bilateral symmetrical involvement of bones. Most of the lesions were located in tubular bones, in 87?% adjacent to one or both sides of a growth plate. 32?% of lesions showed periosteal involvement. Of 456 affected bones, 33 (7.2?%) were deformed, 6 (18?%) were vertebra plana. Conclusion: In the absence of more specific diagnostic criteria, WB-MRI can, in synopsis with clinical findings, substantially contribute to a rapid diagnosis of CRMO. It discovers the typical pattern of multifocal and bilateral bone involvement more often than has been reported for targeted MRI. It readily reveals the characteristic proximity of lesions to growth plates, the sacroiliac joint and triradiate cartilage and helps to uncover asymptomatic spinal complications.