*4.3.4 Acinic cell carcinoma (AciCC)*

It is a low-grade tumour having predominantly vacuolated cell morphology. AciCC predominantly occurs in parotid (75–90%) and the remaining cases occur in intraoral minor salivary glands predominantly in buccal mucosa [39].

**Key cytological features –** Smears are cellular and consist of cells in threedimensional clusters, sheets, micro-acinar groups and papillae with scant inconspicuous fibrovascular stroma. The cells are large with abundant fragile vacuolated basophilic to eosinophilic cytoplasm [40]. The nuclei are round, uniform with bland chromatin. Sometimes, the cells show oncocytic or clear cell changes. The background is clean with presence of bare stripped nuclei. The papillary cystic variant also has cells similar to conventional AciCC but the cells are arranged in a predominant papillary pattern with cells attached to a capillary meshwork or around a fibrovascular core (**Figure 9**). The cytoplasmic zymogen granules in AciCC can be demonstrated by PAS-D stain. Recent studies of IHC on cell blocks with DOG 1 reveals strong diffuse granular cytoplasmic positivity in AciCC [41].

#### **Diagnostic challenges and pitfalls – Acinic Cell Carcinoma (AciCC)**


*Cytopathology of Intraoral Salivary Gland Tumours and Tumour-Like Lesions… DOI: http://dx.doi.org/10.5772/intechopen.98872*
