Laboratory Studies

The clinical presentation (especially the additional presence of a hallus valgus deformity) is suggestive of fibrodysplasia ossificans progressiva (FOP). Routine biochemical study results of mineral metabolism are usually within the reference range. In fibrodysplasia ossificans progressiva, increased alkaline phosphatase levels are characteristic for children (physiologic growth of the bones).

Imaging Studies

Changes associated with fibrodysplasia ossificans progressiva (FOP) include abnormal formation of the great toe, abnormally shaped long bones with exostoses, and developmental fusion of cervical vertebrae.

The most characteristic features are areas of bony masses penetrating into muscles (mainly the paraspinal region).

CT scanning is the best method for detection of early fibrodysplasia ossificans progressiva lesions.^[32]Bone scintigraphy shows an increased uptake of radiolabeled diphosphonate before ossification can be demonstrated by radiographic examination.

CT evaluation may demonstrate heterotopic ossification of the pterygoid muscles, a likely cause jaw restriction and retrognathia in older patients.^[33]

Procedures

A biopsy is generally not indicated in fibrodysplasia ossificans progressiva (FOP) because of the frequent development of the lesions in the traumatization area.

Histologic Findings

Histologic examination shows a pronounced proliferation of fibroblasts within the muscles in several areas, leading to destruction of muscle fibers. Predominate mononuclear cell infiltrates are present within the muscles and in the subcutaneous connective tissue, with extensive proliferation of connective tissue fibroblasts replacing damaged muscle fibers, plus areas of newly formed bone tissue. In the center of fibrous material, bone or cartilage tissue may be detected. The well-developed osseous lesions show a typical picture of mature bone with Haversian systems. The muscle fibers usually secondarily degenerate. Smooth muscles are not involved. Note the image below.

Proliferation of fibroblasts within the muscle with partial replacement of the muscle fibers.

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Treatment & Management

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Media Gallery

Widespread tumors and indurations mainly in the scapular area, found on radiographic examination to consist of heterotopic bone formation.
Typical hallus valgus deformity.
Proliferation of fibroblasts within the muscle with partial replacement of the muscle fibers.

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Author

Robert A Schwartz, MD, MPH Professor and Head of Dermatology, Professor of Pathology, Professor of Pediatrics, Professor of Medicine, Rutgers New Jersey Medical School

Robert A Schwartz, MD, MPH is a member of the following medical societies: Alpha Omega Alpha, American Academy of Dermatology, New York Academy of Medicine, Royal College of Physicians of Edinburgh, Sigma Xi, The Scientific Research Honor Society

Disclosure: Nothing to disclose.

Coauthor(s)

Slawomir Majewski, MD Professor and Director, Department of Dermatology and Venereology, Warsaw School of Medicine, Poland

Disclosure: Nothing to disclose.

Specialty Editor Board

David F Butler, MD Former Section Chief of Dermatology, Central Texas Veterans Healthcare System; Professor of Dermatology, Texas A&M University College of Medicine; Founding Chair, Department of Dermatology, Scott and White Clinic

David F Butler, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Dermatology, Association of Military Dermatologists, Phi Beta Kappa, Texas Dermatological Society

Disclosure: Nothing to disclose.

Jeffrey J Miller, MD Associate Professor of Dermatology, Pennsylvania State University College of Medicine; Staff Dermatologist, Pennsylvania State Milton S Hershey Medical Center

Jeffrey J Miller, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Dermatology, Society for Investigative Dermatology, Association of Professors of Dermatology, North American Hair Research Society

Disclosure: Nothing to disclose.

Chief Editor

Dirk M Elston, MD Professor and Chairman, Department of Dermatology and Dermatologic Surgery, Medical University of South Carolina College of Medicine

Dirk M Elston, MD is a member of the following medical societies: American Academy of Dermatology

Disclosure: Nothing to disclose.

Additional Contributors

Jean Paul Ortonne, MD Chair, Department of Dermatology, Professor, Hospital L'Archet, Nice University, France

Jean Paul Ortonne, MD is a member of the following medical societies: American Academy of Dermatology

Disclosure: Nothing to disclose.

Sebastian S Majewski †

Disclosure: Nothing to disclose.

Stefania Jablonska, MD † Former Chairman, Professor Emeritus, Department of Dermatology, Warsaw School of Medicine, Poland

Disclosure: Nothing to disclose.