A Rare Case of Aneurysmal Bone Cyst of Calcaneum: A Case Report

IntroductIonAneurysmal bone cysts (ABC) manifest as cystic, locally aggressive, and expansible bone lesions.They are typically benign and commonly found in the pediatric age-group, representing 1-6% of all primary benign bone tumors. 1 There is a slight preponderance in the female population, with an estimated male and female sex ratio of 1:1.16. 2 The long bone metaphysis is primarily (67%) affected by ABCs.They are also seen arising in the spine (15%) and pelvis (9%). 3Most patients present with an insidious onset of pain and swelling of the affected part.The term "aneurysmal bone cyst" is inaccurate, as these growths do not exhibit characteristics of an aneurysm nor do they possess a true cystic structure due to the absence of an endothelial wall.Instead, these nonmalignant, expansive lesions generate hollow spaces within the bone, which become filled with blood and are surrounded by proliferative fibroblasts, giant cells, and trabecular bone (Fig. 1). 4,5Microscopically, they are multiloculated cystic lesions with multiloculated giant cells filled with blood and hemorrhage.Basophilic calcified material, known as "blue reticulated chondroid-like material," may be detected within the walls of the cyst. 6adiograph shows cystic lesions exhibit slender "eggshell" sclerotic borders.Within the enclosed cavity, numerous dividing septa are present. 7Evaluation of these lesions is done by computed tomography (CT) (Fig. 2) and magnetic resonance imaging (MRI).An open biopsy is a must to confirm the provisional diagnosis. case descrIptIonA 19-year-old male patient arrived at our outpatient department complaining of heel discomfort that had persisted for 3 months.A history of trauma or other significant history is not presented.The pain was insidious in onset and progressed to the present stage.On examination, heel swelling and tenderness were found.Ankle and subtalar movements were normal.