Nodular fasciitis of parotid region: A pitfall in the diagnosis of pleomorphic adenomas on fine‐needle aspiration cytology

Abstract

Fine-needle aspiration cytology (FNAC) is routinely employed for the preoperative diagnosis of salivary gland lesions. Although most cases show morphologic features characteristic of specific entities, some lesions can be diagnostically challenging. We report two parotid aspirates, initially diagnosed as pleomorphic adenoma on FNA. The patients, a 33-yr-old white man, and a 24-yr-old white woman, presented with indurated lesions arising in the parotid gland region. The aspirates from both patients were markedly hypercellular. Smears showed a mixture of spindle cells with a well-demarcated cytoplasm showing occasional long cytoplasmic process; and cells with abundant cytoplasm with round to oval eccentric nuclei, giving the impression of plasmacytoid cells of pleomorphic adenoma. The nuclear chromatin was evenly distributed and finely granular with one or two occasional small nucleoli. Intermingled with the tumor cells were scattered neutrophils, eosinophils, and macrophages. Aggregates of spindle cells were also seen embedded in a mucoid background with occasional small tufts of a fibrillar mucoid stroma. These fibrillar tufts were magenta red in the Diff-Quik stain, giving the impression of matrix of pleomorphic adenoma. Both cases were later diagnosed on histologic examination as nodular fasciitis. Nodular fasciitis should be considered in the differential diagnosis of a mass arising in association with the parotid gland.

Nodular Fasciitis: Definitive Diagnosis by Fine Needle Aspiration

“…In the light of the different managements of these 2 lesions, careful distinction by adequate FNAB is essential [12,13,14,15,16,17]. Accurate diagnosis by FNAB can provide reassurance to the clinical team when deciding to observe the lesion for regression, rather than to excise it for diagnosis.…”

Cytologic Diagnostic Accuracy in Pleomorphic Adenoma of the Salivary Glands During 2 Periods

“…Similar errors, as well as others, have been reported in the medical literature. [6][7][8][9][10] They represent a small percentage of the total number of errors (11.9% in our series). The second, and more important group, concerns those that show a repetitive pattern.…”

Parotid Gland Nodular Fasciitis: A Clinicopathologic Series of 12 Cases with a Review of 18 Cases from the Literature

“…NF in more usual locations is frequently incorrectly considered a malignant lesion due to its rapid growth, presence of a high cellularity, abundant mitotic figures, and capacity to be poorly circumscribed, and NF of the parotid gland is Other malignancies (dermatofibrosarcoma protuberans, myxofibrosarcoma, rhabdomyosarcoma, angiosarcoma) are rarely included in the histologic or cytologic differential diagnosis [11,16,18,22,23,27,28,30]. Needless to say, this is a broad reactive and neoplastic differential Fig.…”