The spine in fibrodysplasia ossificans progressiva: a case report

Fibrodysplasia ossificans progressiva (stone man syndrome): a case report

Background

Fibrodysplasia ossificans progressiva is an ultrarare autosomal dominant disorder and disabling syndrome characterized by postnatal progressive heterotopic ossification of the connective tissue and congenital malformation of the big toes. Fibrodysplasia ossificans progressiva has worldwide prevalence of about 1 in 2 million births. Nearly 90% of patients with fibrodysplasia ossificans progressiva are misdiagnosed and mismanaged and thus undergo unnecessarily interventions. So far, the number of reported existing cases worldwide is about 700. Clinical examination, radiological evaluation, and genetic analysis for mutation of the ACVR1 gene are considered confirmatory tools for early diagnosis of the disease. Association of fibrodysplasia ossificans progressiva with heterotopic ossification is well documented; however, postsurgical exaggerated response has never been reported previously, to the best of our knowledge.

Case presentation

We report a case of a 10-year-old Pakistani boy brought by his parents to our institution. He had clinical and radiological features of fibrodysplasia ossificans progressive and presented with multiple painful lumps on his back due to hard masses and stiffness of his shoulders, neck, and left hip. He underwent surgical excision of left hip ossification followed by an exaggerated response in ossification with early disability. Radiological examination revealed widespread heterotopic ossification. All of his laboratory blood test results were normal.

Conclusion

Fibrodysplasia ossificans progressiva is a very rare and disabling disorder that, if misdiagnosed, can lead to unnecessary surgical intervention and disastrous results of early disability. We need to spread knowledge to physicians and patients’ family members about the disease, as well as its features for early diagnosis and how to prevent flare-up of the disease to promote better quality of life in these patients.

Fibrodysplasia ossificans progressiva: case report

Fibrodysplasia ossificans progressiva (FOP) is a rare autosomal dominant disorder characterized by postnatal progressive heterotopic ossification of the connective tissue and congenital malformation of the big toes. We report on a nine-year-old girl with clinical and radiological features of FOP. She was born with bilateral hallux valgus and at the age of nine presented an indurate mass in the left cervical region that was painful. A significant decreased range of motion in all levels of the spine and shoulder girdle was found. The radiographs showed heterotopic ossification in the thoracic region. The patient had two outbreaks of the disease ("flare-ups") that were treated with prednisone 2 mg/kg/day for four days. After the "flare-ups", she had a continuous therapy with a Cox-2 inhibitor (25 mg/day) and a leukotriene inhibitor, montelukast (10 mg/day).

Developmental anomalies of the cervical spine in patients with fibrodysplasia ossificans progressiva are distinctly different from those in patients with Klippel-Feil syndrome: clues from the BMP signaling pathway

STUDY DESIGN

A radiographic analysis of the cervical spine of 70 patients diagnosed with fibrodysplasia ossificans progressiva (FOP) and 33 diagnosed with Klippel-Feil (KF) syndrome was conducted.

OBJECTIVES

The objectives of this study were to describe cervical spine abnormalities in patients with FOP, to compare and contrast those findings with the malformations in patients with KF syndrome, and to examine the possible etiology of these abnormalities.

SUMMARY OF BACKGROUND DATA

Congenital features of diseases often provide seminal clues to underlying etiology and developmental pathways. While progressive metamorphosis of connective tissue to heterotopic bone is the most dramatic and disabling feature of FOP, less severe congenital anomalies of the skeleton are also present. Vertebral fusions observed in KF are consistent with defects in embryonic segmentation.

METHODS

The cervical spine plain films of 70 FOP patients and 33 KF patients with documented congenital abnormalities were reviewed.

RESULTS

Generalized neck stiffness and decreased range of motion were noted in most children with FOP. In the FOP patient group, characteristic anomalies, including large posterior elements, tall narrow vertebral bodies,and fusion of the facet joints between C2 and C7, were observed. Most notably, these characteristic anomalies of the cervical spine in patients with FOP were distinctly different from those of 33 patients with KF that were examined but were strikingly similar to those seen in mice with homozygous deletions of the gene-encoding noggin, a bone morphogenetic protein (BMP) antagonist.

CONCLUSIONS

FOP patients exhibit a characteristic set of congenital spine malformations. While the noggin gene (NOG) is not mutated in patients who have FOP, these findings extend a growing body of evidence implicating overactivity of the BMP signaling pathway in the molecular pathogenesis of FOP.