STUDY DESIGN: A case report. OBJECTIVES: Nodular fasciitis is a non-neoplastic soft-tissue lesion located in the deep subcutaneous region; it may be misdiagnosed as a malignant tumor due to its rapid growth and microscopic characteristics. We introduce an unusual case of nodular fasciitis which presented as a posterior neck mass. SUMMARY OF LITERATURE REVIEW: Nodular fasciitis is an unusual benign lesion.Becaue it sometimes shows aggressive microscopic characteristics, (being hypercellular and polymorphic), the condition has the potential to be misdiagnosed as sarcoma. MATERIALS AND METHODS: A 20-year-old woman presented with a 1-month history of a progressively enlarging mass on her posterior neck. Computed tomography (CT) scans of the neck showed a markedly enhanced, well-defined, ovoid soft tissue mass at the posterior of the spinous process of C2. The patient underwent marginal excision. There was a 2 cm, well-capsulated, pinkish-gray mass. RESULTS: She recovered without any complications. Histopathologic examination showed a spindle cell proliferation, increased cellularity, and nuclear atypia with mitosis. The immunohistochemistry stain showed negative findings. The mass was diagnosed as nodular fasciitis. CONCLUSIONS: A diagnosis of nodular fasciitis, not just malignant tumor, should be considered for a rapidly growing posterior neck mass showing aggressive microscopic appearance, Nodular fasciitis is a self-limiting lesion readily treated by marginal excision. However, follow-ups should be increased to watch for recurrence.