Further Classification of Epithelial Lesions of the Salivary Gland
MP Gailey, RA Robinson, CS Jensen, MB Cohen, RA Askeland, L Dahmoush. University of Iowa Hospitals and Clinics, Iowa City, IA
Background: Fine needle aspiration (FNA) is beneficial in planning for surgical excision of salivary gland neoplasms. Certain cases are unable to be definitively diagnosed by aspiration due to technical insufficiencies, overlap in cytology and the necessity to examine the histopathology of the excised lesion. Indeterminate cases represent both benign and malignant lesions. Further classification of salivary gland lesions at FNA may allow better surgical management.
Design: A search of the laboratory information system from January 1990 to June 2009 identified 19 salivary FNAs signed out as an indeterminate epithelial lesions. All had surgical excision. Slides from these cases were distributed to 5 experienced cytopathologists who were blinded to the final diagnosis for their retrospective interpretation, including assessment of malignancy (benign, indeterminate, malignant), and further classification if possible with important criteria.
Results: The 19 cases identified included 13 malignant lesions (metastatic squamous carcinoma, 3; mucoepidermoid carcinoma, low grade, 2; mucoepidermoid carcinoma, high grade, 1; salivary duct carcinoma, 1; adenosquamous carcinoma, 1; adenoid cystic carcinoma, high grade, solid type, 1; carcinoma ex-pleomorphic adenoma in situ, 1; basal cell adenocarcinoma, 1; polymorphous low grade adenocarcinoma, 1; acinic cell carcinoma, 1) and 6 benign lesions (chronic sialadenitis, 2; pleomorphic adenoma, 1; Warthin's tumor, 1; basal cell adenoma 1; multinodular oncocytic hyperplasia, 1). 3 of 6 benign lesions were consistently called benign by all reviewers. 6 of 13 malignant lesions were consistently called malignant. No individual criteria were important in distinguishing these cases.
Conclusions: Indeterminate salivary gland FNAs are relatively uncommon, reflecting the well established cytologic criteria. Although pathologists should attempt precise classification of all salivary gland FNAs, it is important to recognize that a subset of cases remain impossible to classify by FNA alone. The following points were noted on review: 1. Indeterminate cases may represent either benign or malignant lesions and the latter may be either primary or metastatic. Primary neoplasms were a spectrum of lesions and morphologies. 2. Indeterminate lesions are more likely to be malignant on follow-up. 3. A subset of indeterminate cases was reliably categorized as benign or malignant on review, thus this categorization should be done, if possible, in otherwise indeterminate cases.
Wednesday, March 24, 2010 1:00 PM
Poster Session VI # 54, Wednesday Afternoon