Nodular fasciitis of the parotid gland. Report of a case with presentation in an unusual location and cytologic differential diagnosis.

The histomorphology of nodular fasciitis (NF), a benign proliferation of myofibroblasts, is well described in the surgical pathology literature. The cytomorphology, however, has been reported infrequently. Cytologic interpretation of this pseudosarcomatous lesion is subject to the same pitfalls so frequently reported for histologic material. NF arises most commonly in the extremities or trunk; occurrence in the parotid gland is relatively uncommon. We describe a case of NF arising in association with the parotid gland; review the clinical, cytologic, histologic and immunohistochemical features of NF; and offer a differential diagnosis, based on cytologic features, of other benign and malignant lesions likely to be encountered at this location.