The natural history of hereditary multiple exostoses.

What is the Proportion of Patients With Multiple Hereditary Exostoses Who Undergo Malignant Degeneration?

“…Perhaps the most important complication of the benign lesions that are the hallmark of multiple hereditary exostoses is their malignant transformation to chondrosarcoma. Numerous studies have reported proportions from less than 1% to 25% for malignant degeneration of a benign exostosis to chondrosarcoma in patients who have multiple hereditary exostoses [3,4,[7][8][9][11][12][13][14]. In general, malignant transformation is rare and the true incidence has (1), and South Korea (1).…”

“…They also noted that 22% of their cohort required deformity correction. In a cohort of 143 patients, Schmale et al [13] noted that 74% required surgery to remove at least one osteochondroma and the average patient required three surgical procedures related to their diagnosis of multiple hereditary exostoses. Our results showed that, of respondents who answered whether they have had surgery, 70.8% (418/590) have had at least one surgical procedure.…”

“…Multiple hereditary exostoses, also known as multiple osteochondromatosis, is a relatively rare autosomal-dominant skeletal disorder that affects approximately one in 50,000 individuals [13]. The condition is a genetically heterogeneous disorder that has been linked to mutations of the genes EXT1 [2] and EXT2 [15,16], with a reported penetrance of 96% [9].…”

“…Previous studies have shown a wide range in the numbers of patients with multiple hereditary exostoses who have had malignant change to chondrosarcoma, and these studies [3,7,8,[12][13][14] cite proportions derived from smaller population clusters in seemingly isolated geographic areas. Historically, reported proportions of transformation have ranged from less than 1% to approximately 25% [3,4,[7][8][9][11][12][13][14]. Some of the larger studies we are aware of include rates of 4.9% in 529 patients [11], 0.38% in 526 patients [8], and 7% in 184 patients [4].…”

Bilateral sandwiched scapulae: A rare presentation of hereditary multiple exostoses

“…The prevalence of multiple hereditary exostoses is estimated at 1:50,000 persons within the general population with male predilection (male-tofemale ratio: 1.5). [2][3][4] Although different parts of scapula could be involved by osteochondroma, involvement of ventral surface is more common than dorsal one. [5][6][7] To the best of our knowledge, involvement of both ventral and dorsal surfaces of bilateral scapulae in one patient has not been reported yet.…”