Perineural invasion and nerve morphometry in oral squamous cell carcinoma and their correlation with other prognostic markers – A cross-sectional study.

The oral cavity is formed by the arch of the hard and soft palate above, the teeth and cheeks laterally, and the tongue on the floor of the mouth. All oral lesions are divided in to three groups including non neoplastic lesions, potentially malignant disorders and neoplastic lesions.1 Neoplastic lesions include squamous cell carcinomas most commonly, papillomas, soft tissue and neural tumors ,oral mucosal melanomas, salivary type tumours and haematolymphoid tumors like lymphomas, extramedullary myeloid sarcoma.2 Oral cancer arising from the oral mucosal epithelium is a major health problem worldwide. It represents 2% of all new cancers worldwide.3 It is more common in men (5.5 cases per lakh population) than women (2.5 cases per lakh population).It is associated with severe morbidity ,recurrence and reduced survival rates. The most common cause of oral cancers are tobacco chewing and alcohol. Others are Human Papilloma Virus type 16, poor oral hygiene, occupational exposure, malnutrition, chronic irritation. Oral tumors shows exophytic or verrucous growth, most commonly seen in the tongue, floor of mouth and gingiva.4-5 Diagnosis of oral squamous cell carcinoma is confirmed by biopsy and histopathology. Histopathologically the SCC are classified as well, moderately differentiated, poorly differentiated.6

Conventionally oral SCC are aggressive and prognostic factors have an impact on its morbidity ,recurrence and encompass various clinicopathologic factors like grade ,tumour size, nodal status, distant metastasis, lymphovascular invasion(LVI), worst pattern of invasion(WPOI) and perineural invasion(PNI).PNI is a form of tumor spread exhibited by malignancies which are neurotropic in nature and correlates with aggressive behavior, disease reccurence and mortality. Incidenceof PNI in head and neck is as high as 80%.7