From the Guidelines
Exostosis, particularly in the context of hereditary multiple osteochondromas (HMO), requires regular surveillance for potential malignant transformation into chondrosarcoma, with the recommendation of annual physical examinations starting from birth and whole-body MRI (WBMRI) considered in early adolescence as a baseline. The management of exostosis involves a comprehensive approach, considering the risk of malignant transformation and the potential for symptoms such as pain, deformities, and functional impairment.
- Key aspects of management include:
- Regular physical examinations to monitor for changes in the size or characteristics of osteochondromas
- Imaging studies, such as plain radiographs and WBMRI, to assess the extent and potential complications of osteochondromas
- Consideration of surgical removal for symptomatic osteochondromas or those causing significant impairment
- Surveillance for secondary chondrosarcomas, particularly in individuals with an EXT1 pathogenic variant (PV) and in males 1. The risk of malignant transformation into chondrosarcoma, although relatively low (0.2% to 5.9%), necessitates a high index of suspicion, especially in individuals with specific genetic predispositions or those presenting with new or worsening symptoms 1.
- Factors influencing the risk of malignant transformation include:
- Genetic predisposition, with EXT1 PVs associated with a higher risk
- Male gender
- Presence of multiple or large osteochondromas
- Increasing age, with most secondary chondrosarcomas occurring between 20 and 40 years of age 1. Given the potential for significant morbidity and mortality associated with malignant transformation, a proactive and vigilant approach to surveillance and management of exostosis is essential, prioritizing regular monitoring, prompt evaluation of new or changing symptoms, and consideration of preventive measures to minimize the risk of complications 1.
From the Research
Definition and Types of Exostosis
- Exostosis refers to a benign growth of bone that can occur in various parts of the body, including the external auditory canal, metatarsocuneiform joints, and spine 2, 3, 4, 5.
- There are different types of exostosis, including external auditory canal exostoses, osteomata, and spinal exostoses 2, 3, 5.
Symptoms and Complications
- Symptoms of exostosis can include hearing loss, ear fullness, and pain 2, 3.
- Complications of surgical removal of exostoses can include tympanic membrane perforation, postoperative hearing loss, canal stenosis, and facial nerve injuries 2, 3.
- In some cases, exostosis can cause bursitis and neuritis, particularly in the metatarsocuneiform joints 4.
Treatment and Surgical Outcomes
- Surgical removal of exostoses is often reserved for cases where conservative treatment has failed 2, 3, 4.
- The choice of surgical approach can depend on the location and size of the exostosis, as well as the patient's overall health 6.
- Studies have shown that surgical removal of exostoses can be effective in relieving symptoms and improving quality of life 2, 3, 4, 5.
- Comparison of microscopic and endoscopic ear surgery techniques for exostosis removal has shown that endoscopic approach may be preferred due to improved view and decreased operative time 6.
Surgical Techniques and Considerations
- Meatal skin preservation and tympanic membrane protection are important considerations in exostosis surgery to avoid postoperative complications 2, 3.
- The use of circular meatal flap incision should be avoided to prevent postoperative canal stenosis 3.
- In cases of preexisting sensorineural hearing loss, attention should be focused on intraoperative noise reduction by tympanic membrane protection and pauses of noise exposition 3.