Type of Preparation:
Direct Smear
Magnification:
Low Power Magnification
Clinical History:
61-year old male with left parotid mass showing mucoid background
Interpretation:
Fig. 4.7 Atypia of Undetermined Significance (AUS)
Cytomorphologic Criteria:
This aspirate contains abundant mucin without any epithelial cells. The differential diagnosis includes a benign mucinous cyst; however, a low-grade mucoepidermoid carcinoma cannot be excluded.
Explanatory Notes:
A variety of neoplastic and non-neoplastic lesions of the salivary glands can
present with a predominant cystic component, with at least one-third of cystic salivary gland lesions being neoplastic. FNAs of these lesions often yield serous or mucoid material, frequently of low cellularity. Such aspirates may be obtained from non-neoplastic lesions including mucus retention cysts, mucoceles, ductal cysts, and lymphoepithelial cysts as well as cystic neoplasms such as Warthin tumor, cystic pleomorphic adenoma, low-grade mucoepidermoid carcinoma, and cystadenoma/cystadenocarcinoma. Aspirates with sufficient cellularity usually lead
to a specific diagnosis. However, cases containing mucinous cyst contents only and/or a sparse epithelial component can pose diagnostic difficulties. In these cases, the aspirate can be classified as AUS. Aspirates of cystic salivary gland lesions can be generally divided into mucinous and non-mucinous types. Aspirates of nonmucinous cyst contents characterized by watery proteinaceous fluid containing scattered lymphocytes, histiocytes, and debris will be classified as “Non-Diagnostic-cyst contents.