A Bony Excrescence

A 15-year-old boy presented with a painless swelling at the back of his neck for the last two years that progressively increased in size. He denied a history of fever, trauma, or tuberculosis. Local examination revealed a hard, non-tender, globular mass in the right posterior triangle of the neck, deep to the trapezius muscle [Figure 1, a and b]. There was no cervical lymphadenopathy or neurological deficit. All the movements of the neck were normal. Anteroposterior and lateral X-rays of the cervical spine showed a soft tissue mass in the neck with specks of calcification within [Figure 1, c and d]. A computed tomography (CT) scan of the neck revealed the presence of a well-circumscribed, round to oval, predominantly fat attenuation lesion seen in the intermuscular plane of the right cervical paraspinal muscles. Multiple ossified trabeculae were seen scattered within the lesion, predominantly along the periphery. The cervical spine was normal. The vertebral, carotid, and jugular vessels were seen away from the mass [Figure 1, e and f ].