Bilateral coronoid hyperplasia: Report of two cases

Bilateral hyperplasia of the coronoid processes of the mandible is an uncommon condition that has been reported in 24 patients.^1-3 The coronoid processes are usually normally shaped,^4,5 and have been classically described by Shira and Lister as "mere overgrowths of bone."⁶ The process has been diagnosed as a developmental hyperplasia, and the etiology has remained unknown.^1,2,5,7 The most common symptom of bilateral coronoid hyperplasia is limitation of mandibular opening without visible facial deformity.^1-3,5,8 The previously reported cases of bilateral coronoid hyperplasia have all been reported in males.^1-3 This has led some authors to speculate that the condition is sex-linked. This paper describes two new cases, one being the first reported in a female.