An osseous choristoma is an uncommon, benign medical condition. This article will provide a clear overview of osseous choristomas for the general public, explaining what they are, how they are identified, and their typical management.
Understanding Osseous Choristoma
An osseous choristoma is a rare, non-cancerous lesion characterized by the presence of normal, mature bone tissue in an unusual anatomical location where bone typically does not exist. It is considered a type of choristoma, which refers to a growth of histologically normal tissue found in an abnormal site. These lesions appear as a mass of normal bony structure with mature cells in an ectopic position. Unlike true neoplasms, osseous choristomas do not exhibit the aggressive, uncontrolled growth patterns of cancerous tumors.
While the exact cause remains unclear, some lesions may represent developmental malformations, while others might be reactive lesions formed after trauma or chronic irritation. Osseous choristomas are most frequently found in the oral cavity, particularly on the tongue, accounting for about 85% of cases. They can also occur in other oral sites, such as the buccal mucosa, alveolar mucosa, and rarely, the periodontium or submental region. In the tongue, they often present in the posterior third, near the foramen cecum.
Identifying and Diagnosing Osseous Choristoma
Osseous choristomas are often discovered incidentally during routine examinations or imaging procedures performed for other reasons, as they can be asymptomatic. When symptoms do occur, they depend on the lesion’s size and location. These may include a foreign body sensation, gagging, discomfort, or difficulty swallowing (dysphagia). They appear as firm, well-defined nodules.
The diagnostic process begins with a clinical examination where the lesion’s consistency and appearance are assessed. Imaging studies, such as X-rays or CT scans, can visualize the bony tissue within the soft tissue, appearing as a radiopaque (dense) mass. However, a definitive diagnosis requires a histopathological examination of a biopsy sample. This microscopic analysis confirms the presence of mature lamellar bone without signs of malignancy.
Management and Prognosis
The primary treatment for an osseous choristoma is surgical excision, which involves the complete removal of the mass. This procedure is performed for several reasons, including obtaining a definitive diagnosis through histopathological examination, alleviating any symptoms the lesion might be causing, or simply removing a foreign body from the soft tissue. Surgical removal can be done under local anesthesia, and laser excision has also been used as an alternative.
The prognosis for individuals with an osseous choristoma is excellent because these lesions are benign and do not spread to other parts of the body (metastasize). After complete surgical removal, recurrence is rare, with only a few cases reported in the literature. Patients experience uneventful healing post-surgery and remain free of the condition.