Abstract
Fibrodysplasia ossificans progressiva (FOP) is a rare hereditary disease characterized by heterotopic ossification of skeletal muscles, tendons, and ligaments. In the oral and maxillofacial region, FOP leads to eating disorders caused by a limited range of mouth opening. At a late stage, respiratory function is impaired by limited movement of the thorax. We reported a rare case of FOP with trismus and discuss the related literature. A 28-year-old woman was referred to our hospital because of trismus in December 2011. She had heterotopic ossification in the left scapula and was given a diagnosis of FOP at the age of 17 years. Extraoral examination showed temporary pain extending from the left temporomandibular joint to the buccal region when she opened the mouth. A maximal mouth opening of 3 mm was confirmed. Intraoral examination showed an inflammatory reaction at the gingiva of the maxillary left third molar. Magnetic resonance imaging showed high intensity of the left lateral pterygoid muscle. Nonsteroidal anti-inflammatory drugs and injectable bisphosphonates were administered, followed by mouth opening training. Her maximal mouth opening markedly improved to 22 mm 1 year after initial presentation, without any recrudescence.
