Mesenchymal neoplasms of the parotid gland and parapharyngeal space: an FNA cytologic study of 22 nonlipomatous tumors

• Published in: Cancer cytopathology 2022-06, Vol.130 (6), p.443-454
• Main Author: Wakely, Paul E.
• Format: Article
• Language: English
• Subjects: adamantinoma‐like Ewing sarcoma; Adult; Aged; Aged, 80 and over; Biopsy; Biopsy, Fine-Needle; Ewings sarcoma; Exocrine glands; Female; fine needle; Humans; Infant; Male; Middle Aged; Parapharyngeal Space; parotid gland; Parotid Gland - pathology; Retrospective Studies; rhabdomyoma; schwannoma; Solitary Fibrous Tumors - pathology; synovial sarcoma; Tumors; Young Adult
• ISSN: 1934-662X; 1934-6638
• DOI: 10.1002/cncy.22562

BACKGROUND Mesenchymal neoplasms of the parotid gland (PG) and para‐pharyngeal (PP) space are distinctly uncommon. Fine‐needle aspiration (FNA) biopsy experience with nonlipomatous neoplasms from this site is reviewed. METHODS Cytopathology and surgical pathology files were examined for mesenchymal PG and PP space neoplasms. FNA biopsy was performed using standard technique. RESULTS Twenty‐two PG and/or PP aspirates from 20 adults (male:female = 1.1:1; age range, 19‐84 years, mean age, 50 years) and a 10‐week‐old infant met inclusion criteria. Biopsy sites included PG (17, 77%) or PP space (5, 23%). Five of 6 malignant neoplasms (83%) were called malignant cytologically. Only 7 of 11 (63%) benign neoplasms were recognized as a benign neoplasm. None of 5 solitary fibrous tumor (SFT) cases were correctly recognized. Conversion to the Milan classification showed 8 (36%) FNA cases diagnosed as benign neoplasm, 6 (27%) malignant neoplasm, 4 (18%) neoplasm of uncertain malignant potential, 2 (9%) nondiagnostic, and single cases of suspicious for malignancy and nonneoplastic. There was 1 false‐positive and no false‐negative FNA diagnoses. Ancillary testing in 10 (45%) aspirates helped substantiate a correct specific diagnosis in 3 malignant and 3 benign cases. CONCLUSIONS FNA biopsy of nonlipomatous mesenchymal SG neoplasms is particularly challenging. Less than half (9 of 11, 41%) had specific FNA diagnoses that correctly matched the tissue diagnoses or clinical outcome. Accurate Milan categorization was superior for malignant neoplasms (5 of 6, 83%) in contrast to benign neoplasms (7 of 11, 63%), or neoplasms of uncertain malignant potential (SFT) (2 of 5, 40%).;