Journal of Clinical and Diagnostic Research. 2017 Dec, Vol-11(12): TD01-TD03 1 1 Case Report DOI: 10.7860/JCDR/2017/32660.10990 Radiology Section Aneurysmal Bone Cyst of C2 Cervical Spine Presenting as an Asymptomatic Posterior Neck Swelling CASE REPORT An eight-year-old girl presented with a history of palpable swelling at the nape of neck for two years. There was no history of trauma to that region. The lesion was slowly growing over a period of two years to the present size of 4×2 cm. Her general examination was unremarkable. On local examination, she had a 4×2 cm bony, immobile swelling in the midline posterior neck without local warmth or tenderness. There was discolouration of overlying skin [Table/Fig-1]. There was no restriction of neck movements or any neurological deficits. No conclusive clinical diagnosis could be made at this point except bony nature of the lesion. PRADOSH KUMAR SARANGI 1 , JAYASHREE MOHANTY 2 , SASMITA PARIDA 3 , BASANTA MANJARI SWAIN 4 , SUNIL KUMAR 5 Keywords: Back pain, Fluid-fluid level, Palpable mass, Tumour ABSTRACT Aneurysmal Bone Cysts (ABC) are benign tumour-like expansile lytic lesions commonly affecting metaphysis of long bones. They are relatively rare in vertebral column accounting for about 12 to 30% of all ABC cases, predominantly involving posterior elements. ABC of cervical spine account for only 2% cases. They commonly present as back pain, palpable mass, spinal deformity, rarely pathological fracture and neurological deficit (paraplegia, cord compression, and cauda equina syndrome). Surgical treatment of ABC of cervical spine in paediatric patients is challenging because of proximity of lesions to neurovascular structures and the potential remaining growth of the spine. Here, we report a case of ABC of C2 vertebra with isolated posterior arch involvement who presented with a palpable posterior nuchal swelling and skin discoloration without any neurological deficit or difficulty in neck movement. Biopsy led to the definite diagnosis of ABC. [Table/Fig-1]: Swelling at the posterior neck region, overlying skin appears discoloured. [Table/Fig-2]: X-ray neck lateral view showing a sharply defined multiloculated expansile lesion with narrow zone of transition involving posterior element of C2 (axis vertebra). [Table/Fig-3]: Non-contrast CT axial; a) and sagittal; b) bone window showing a multiloculated expansile lytic lesion involving C2 posterior element without any soft tissue component without any evidence of spinal canal narrowing. 3D CT with volume rendering technique; c,d) nicely depicting the origin of lesion from C2 posterior element. The lesion extends caudally up to C4 spinous process. Lateral radiograph of cervical spine demonstrated a sharply defined, expansile osteolytic lesions (characteristic ballooning appearance) with thin sclerotic margins involving posterior element of C2 vertebra without any matrix mineralisation [Table/Fig-2]. Computed tomography (CT) was done to know the extent of lesion [Table/ Fig-3a,b]. It showed a multiloculated expansile lytic lesion of size (4×2×2.5) cm involving C2 posterior element without any soft tissue component or fluid-fluid level. There was no evidence of spinal canal narrowing. Three Dimensional CT with Volume Rendering Technique (VRT) nicely depicted the origin of lesion from C2 posterior element. The lesion extended caudally up to C4 spinous process [Table/Fig-3c,d]. Magnetic Resonance Imaging (MRI) of the cervical spine revealed T1 isointense and T2 intermediate signal intensity lobulated expansile mass lesion with T2 hyperintense components involving spinous process and lamina of C2 vertebra. There was no spinal cord involvement. Normal flow void noted