<p>Cystadenomas are rare benign salivary gland tumours characterised by prominent epithelium-lined papillary projections into the cystic spaces. Cystadenoma accounts for 2% of all salivary gland tumors, occurring most commonly in major salivary glands. Histopathologically there are two variants, papillary and mucinous variant. However very few cases are being reported in literature. We report a case of papillary cystadenoma occuring in parotid gland in a 28 year old male patient. Clinically, it presents as a soft, fluctuant, sessile and non-tender swelling measuring about 4×3.5 cm in diameter. Excisional biopsy was performed. The histopathological features were characteristic of papillary cystadenoma. This article highlights its clinical and histopathological features along with review of literature. </p>

BACKGROUND A large area of the genetically altered area around the tumour proper that appears clinically normal is called field cancerization. This field subsequently influences the prognosis as it can root to second field tumours i.e. recurrence or second primary tumours. Field cancerization has been described in the oral cavity, oropharynx, larynx; lung, vulva, oesophagus, cervix, breast, skin, colon and bladder. Studies have shown a comparatively higher frequency of local recurrences and second primary tumours after surgical resection in betel chewers than non-chewers probably due to the existence of field cancerization.

BACKGROUND DNA mismatch repair (MMR) has an exclusive chapter in maintaining DNA replication fidelity, mutation avoidance and genome stability. At mechanistic level MMR is quite complex in eukaryotes than prokaryotes. In recent years, many MMR-deficient human cancers specifically hereditary nonpolyposis colorectal cancer (HNPCC), also known as Lynch syndrome (LS), and associated endometrial cancer are allied to mutations in MMR genes. Most of the proteins involved in this pathway are predictably tumour suppressors and defects in the MMR genes convene a strong predisposition for cancer. This review summarizes the literature on MMR, emphasising the role of different MMR proteins in the repair pathway.