Progressive osseous heteroplasia: an uncommon cause of ossification of soft tissues.

Whereas the deposition of calcium within soft tissues is not infrequent, the development of highly structured, mineralized tissue histologically identifiable as true bone is uncommon and can cause a variety of clinical features. This article reports the clinical and radiological features in a patient with progressive osseous heteroplasia (POH), a recently identified disorder characterized by heterotopic ossification. The patient, a female, was 20 years of age at presentation. In addition to abnormal ossifications, she had short metacarpals at the fourth and fifth rays and short metatarsals at the second rays. Her parents were unaffected. Until the results of Rosenfeld and Kaplan in 1995 reporting POH in two boys, typical features had only been reported in females (n=8). POH is usually sporadic; however, familial associations and atypical phenotypes have been reported.