Imaging Findings of Calcaneal Cyst and Lipoma: Can Intraosseous Cyst Changes Into Lipoma With Advancing Age?

ABSTRACT

OBJECTIVE: Recent studies have indicated that intraosseous lipomas originate from simple bone cysts of the calcaneus. This study evaluates computed tomography (CT) and magnetic resonance imaging (MRI) findings of calcaneal cysts and lipomas in pediatric and adult populations. METHODS: Forty-six patients with bone lesions located in the anterior portion of the calcaneus beneath the talocalcaneal joint, who underwent CT and/or MRI, were enrolled in this study. The imaging characteristics were retrospectively reviewed and compared between the pediatric (aged 18 years or younger; n = 29) and adult (aged 19 years or older; n = 17) groups. RESULTS: On CT images, water/soft tissue attenuation alone was more frequent in the pediatric group than in the adult group (84% vs 13%, respectively; P < 0.01), whereas the combined water/soft tissue and fat attenuation (11% vs 47%, respectively; P < 0.05) and fat attenuation alone (5% vs 40%, respectively; P < 0.05) were less frequent in the pediatric group than in the adult group. On MRI, cystic components alone were more frequent in the pediatric group than in the adult group (88% vs 13%, respectively; P < 0.01), whereas the combined cystic and fat components (8% vs 38%, respectively; P < 0.05) and fat components alone (4% vs 50%, respectively; P < 0.01) were less frequent in the pediatric group than in the adult group. CONCLUSIONS: Calcaneal cysts were more frequent in the pediatric group, whereas calcaneal lipomas were more frequent in the adult group. These results could be additional evidence that intraosseous lipomas originate from simple bone cysts of the calcaneus.