NUCHAL FIBROCARTILAGINOUS PSEUDOTUMOR - A DISTINCTIVE SOFT-TISSUE LESION ASSOCIATED WITH PRIOR NECK INJURY

Soft-tissue tumors with a predilection to involve the head and neck re gion include spindle cell lipoma, pleomorphic lipoma. and nuchal fibro ma. We have recently studied three patients with distinctive soft-tiss ue fibrocartilaginous masses in the pos terior aspect of the base of t he neck, at the junction of the nuchal ligament and the deep cervical fascia. Two of the patients were women (ages 37 and 40) and one a man (age 53). All three had sustained neck injuries in automobile accident s in the past (27 years, 20 years, and 2 months before surgery, respec tively). Each patient presented with a soft-tissue nodule overlying th e spinous process of one of the lower cervical vertebrae. Two were pai nful. Computed tomography and magnetic resonance imaging performed in two patients showed focal thickening of the ligamentum nuchae at the C 4-5 and C5-6 levels. All three masses were completely excised. They ra nged in size from 1.0 to 1.5 cm. The three lesions were histologically identical, and each consisted of a poorly defined, moderately cellula r fibrocartilage nodule located within the nuchal ligament at its junc tion with the deep cervical fascia. Atypia or mitotic activity was not present. The ligamentous tissue adjacent to the mass was irregular an d degenerated. None of the masses have recurred in follow-up periods o f 3 to 6 months and all patients are currently asymptomatic. The lesio n we describe is a distinctive soft-tissue pseudotumor that occurs in the mid-line of the lower cervical spine within the nuchal ligament. I t is likely non-neoplastic and probably develops as a reaction to soft -tissue injury, in an analogous manner to fibrocartilage metaplasia se en in degenerated tendoligamentous structures. We propose the term ''n uchal fibrocartilaginous pseudotumor'' for these lesions.