Pathology Quiz Case

Abstract

A 23-YEAR-OLD MAN PRESENTED WITH A 1-YEAR history of a slow-growing mass in the right side of his neck. He was otherwise healthy, and his medical and surgical histories were unremarkable. He denied having tenderness or numbness of the neck; however, limitation of neck movement was noted. Clinical examination revealed an 8 5-cm, smooth, firm mass fixed to the underlying soft tissues at levels II to IV in the right side of the neck. T1-weighted gadolinium-enhanced magnetic resonance images revealed a well-circumscribed lesion in close contact with the scalene muscles and the branchial plexus (Figure 1); a mild increase in the signal intensity of the mass was observed on T2-weighted images. The mass appeared to extend from the anterior part of the right paraspinal space, with posterior displacement of the right levator scapular muscle, anterior displacement of the carotid sheath, and segmental obliteration of the right internal jugular vein. Only nondiagnostic fibrous tissue was identified in a needle biopsy specimen of the lesion. The mass was subsequently excised in the operating room, and representative histologic sections of the lesion are shown in Figure 2 and Figure 3. What is your diagnosis?