Papillary cystadenoma of the major salivary gland: A case report and review of literature.

Papillary cystadenoma (PC) of the salivary gland is an uncommon benign epithelial neoplasm that shows predominantly multicystic growth pattern with intraluminal papillary proliferation and areas of oncocytic differentiation. We report a case of papillary cystadenoma of the parotid gland in a 44-years-old female. The patient presented with painful nodular swelling in the right parotid region for two months. Ultrasonography revealed a well marginated oval lesion with altered signal intensity involving the superficial lobe. The excision specimen showed a neoplasm with multicystic spaces having papillary projections lined by benign low-grade epithelium and supported by fibrovascular cores. No significant cytological atypia or mitosis was observed. The cells were immunoreactive for Keratin, Keratin 7, and were negative for Keratin 20, AR, HeR2/neu, TTF1, CDX2, and GATA3. p63 and Keratin 5/6 highlighted the myoepithelial cell layer lining the cystic spaces as well as the papillary projections. The Ki-67 proliferation index was 6%. The patient is on close clinical and imaging follow-up for the last 1year and 8 months without any evidence of disease recurrence or metastasis. Rarity of the lesion and distinct histomorphology warrants appropriate knowledge and discussion of the subject.