**Diagnostic challenges and Pitfalls – Cystic Tumours**


#### **Figure 8.**

*8a: Showing small sheets and clusters of epidermoid cells in a cystic mucoid background in a case of lowgrade mucoepidermoid carcinoma (Papanicolaou stain x 10), 8b: Corresponding histology showing sheets of epidermoid cells (Haematoxylin & Eosin x 10).*

cells appear like a metaplastic squamous cell. Mucin filled cells can also be demonstrated by using mucicarmine staining on cell blocks. Sometimes, epithelial cells are not aspirated and aspirate consist of only mucoid material with few histiocytes and muciphages resembling a mucocele [35]. In proper clinical contexts, such cases should be reported with differential diagnosis of low-grade MEC and must be followed-up. High-grade MEC is predominantly solid but can have a cystic component. Smears from a high-grade MEC are cellular and are readily recognisable and shows three-dimensional clusters and sheets of atypical cells with malignant squamoid features. The cells are polygonal and have a high N:C ratio with hyperchromatic nuclei often with a prominent nucleolus. If a high-grade MEC is suspected, search should be done for mucin containing vacuolated cells. Moreover, keratinsation is not the feature of MEC which can aid in distinguishing MEC from metastatic squamous cell carcinoma [35].

