Poor prognosis of oral squamous cell carcinoma developing in young patient without habits along with perineural invasion - A case report with review of literature

Oral squamous cell carcinomas (OSCC) generally occur in older (>50 years) population usually with a history of tobacco and/or alcohol use.[1-3] It is less frequent in young individuals (<40 years) and represents 3–6% of all OSCC. However, the incidence of tongue SCC is gradually increasing since 1973 in a particular group of patients without any known reasons.[4] Usually, tongue SCC with perineural invasion (PNI) in young patient is associated with poor outcome. PNI is a distinct entity of tumor metastasis that can be seen in the absence of lymphatic or vascular invasion. Even, PNI is not an extension of lymphatic metastasis because there are no lymphatic channels within the inner sanctum of the nerve sheath.[5] In 1930s, Jentzer first noted that cancer cells spread along nerves as an additional pathway of invasion.[6] Dissemination of cancer cells along nerve fibers is a frequent pathological finding among several types of malignancy including pancreatic, prostate, upper gastrointestinal tract, and head and neck cancers.[7] PNI is most commonly found in adenoid cystic carcinoma in salivary glands followed by SCC in the head and neck cancer.[8,9] It is mainly involves the vicinity of the primary tumor (92%) compared with near nodal metastasis (8%) and this invasion is not dependent on the size of primary tumor or histological grading of the tumor in case of OSCC.[9]