LIMB SWELLING IN PATIENTS WHO HAVE FIBRODYSPLASIA OSSIFICANS PROGRESSIVA

Fibrodysplasia ossificans progressiva is a rare heritable disorder of connective tissue characterized by progressive heterotopic ossificatio n of soft tissues and by congenital malformation of the great toes, Li mb swelling has also been noted, yet little is known about this compli cation of fibrodysplasia ossificans progressiva. To determine the prev alence of limb swelling in this condition, the authors reviewed detail ed medical records on 74 patients (25 males, 49 females; age range, 1- 49 years) who had a documented history of fibrodysplasia ossificans pr ogressiva. The study population included more than 90% of all patients known to have fibrodysplasia ossificans progressiva in the United Sta tes, Acute swelling of the limbs occurred in association with flareups of the condition in nearly all cases. Acute swelling in the upper lim bs was focal and nodular in contrast to acute swelling in the lower li mbs, which was more diffuse, Acute swelling in the upper limbs occurre d in all 74 patients whereas acute swelling in the lower limbs occurre d in 47 of the 74 patients (64%). Two of the 74 patients who had acute swelling in the lower limbs (4%) had a documented episode of deep vei n thrombophlebitis, Chronic swelling in the upper limbs occurred in 9 of the 74 patients (12%) and was not seen before the age of 12 years, Chronic swelling in the lower limbs occurred in 36 of the 74 patients (49%) and was not seen before the age of 9 years, The intense angiogen esis and edema seen on histopathologic evaluation of preosseous fibrod ysplasia ossificans progressiva lesions may play a role in the pathoge nesis of the limb swelling. The data show an age related prevalence of limb swelling in fibrodysplasia ossificans progressiva and suggest a model for understanding the complex pathways leading to limb swelling in this disorder.