Bone morphogenetic protein 2/4 in early fibromatous lesions of fibrodysplasia ossificans progressiva

• Published in: Human pathology 1997-03, Vol.28 (3), p.339-343
• Main Authors: GANNON, F. H, KAPLAN, F. S, OLMSTED, E, FINKEL, G. C, ZASLOFF, M. A, SHORE, E
• Format: Article
• Language: English
• Subjects: Alkaline Phosphatase - metabolism; Biological and medical sciences; Bone Morphogenetic Protein 2; Bone Morphogenetic Protein 4; Bone Morphogenetic Proteins - metabolism; Collagen - metabolism; Desmin - metabolism; Diagnosis, Differential; Diseases of the osteoarticular system; Fibromatosis, Aggressive - pathology; Humans; Medical sciences; Miscellaneous. Osteoarticular involvement in other diseases; Myositis Ossificans - metabolism; Myositis Ossificans - pathology; Transforming Growth Factor beta; Vimentin - metabolism
• ISSN: 0046-8177; 1532-8392
• DOI: 10.1016/S0046-8177(97)90133-7

Fibrodysplasia ossificans progressiva (FOP) is a rare genetic disorder characterized by congenital malformation of the great toes and progressive heterotopic ossification in distinct anatomic patterns. Early preosseous lesions in FOP are clinically and histologically indistinguishable from the lesions of aggressive juvenile fibromatosis (AJF). Although the genetic defect in FOP is unknown, bone morphogenetic proteins (BMPs) 2 and 4 are plausible candidates genes. To determine if there is a difference in BMP 2/4 expression in the early fibromatous lesions of the two conditions, we performed immunohistochemical studies with a monoclonal antibody to BMP 2/4 on the earliest detectable fibromatous lesions of FOP and compared them with histologically identical lesions resected from children who had AJF. Fibromatous cells from the early FOP lesions exhibited immunostaining for BMP 2/4, whereas histologically indistinguishable fibromatous cells from AJF lesions showed no evidence of BMP 2/4 immunostaining. It is incumbent on all physicians who treat patients with suspected fibromatosis to examine the toes to rule out FOP and to avoid unnecessary diagnostic biopsies because surgical trauma induces further bone formation in patients who have FOP. However, if diagnostic confusion still exists and a biopsy is performed, immunostaining with BMP 2/4 antibody may resolve the diagnostic dilemma between FOP and AJF before the appearance of heterotopic ossification is observed in the FOP lesions. Our data suggest that the BMP 2/4 subfamily of secreted proteins may be involved in the pathogenesis of the FOP lesions.