Endocrine Abstracts

Introduction: Fibrodysplasia ossificans progressiva (FOP), also known as stone man disease, is a rare connective tissue disorder with a prevalence of 1 in 2 million. It is caused by a mutation in ACVR1 gene, usually sporadic and sometimes with autosomal dominant (AD) inheritance. These patients are normal at birth except for the short great toes and hallux valgus. Over time soft tissues such as ligaments, skeletal muscles or tendons ossify. Diaphragm, tongue, extraocular and cardiac muscles are spared.

Clinical case: A 32-year-old female with severe bone pain and hip contracture applied to our clinic. In her history, at age 8 she was admitted to hospital due to lump on her back. The biopsy result of the lesion was reported as fibrotic fat tissue and she was discharged. Two years later at age 10 she was admitted to hospital again due to protrusion and pain in the area where the biopsy was taken. The second biopsy taken from the left thoracic wall was reported as heterotopic endochondral ossification. Further examination of the case for FOP was recommended. Genetic testing could not be done due to the family’s financial difficulties. Over the years, painful swellings continued to develop in various regions. When the patient’s daughter was 5 years old, the same painful swellings began to occur. This time genetic testing was done on both. Mutation was detected positive for ACVR1 gene for both. (NM_001105.5, c.617G>A (p.R206H) (p.Arg206Pro) (Heterozygote)). During our examination, many painful ossification areas were detected in different regions such as the back, dorsum of foot and chest wall. In addition, contracture of the left hip joint occurred in external rotation and abduction. She also had short big toes and hallux valgus. No abnormalities were detected in laboratory tests. In plain radiographs, pseudoexostoses were seen in various parts such as left sided thoracic wall, left iliopsoas muscle and adductor magnus muscle. Also, monophalangic great toes were noted (Figure 1). Since there was no treatment to prevent the progression of the disease, we administered ibuprofen for symptomatic treatment and glucocorticoid to use during painful flare-ups.

Conclusion: FOP is a rare disease that reduces quality and duration of life. Where heterotopic ossification is detected clinically or radiologically, FOP should be kept in mind. Since it can be inherited AD, genetic testing and counseling should be provided in case of clinical suspicion.