A well differentiated oral squamous cell carcinoma involving the lateral border of tongue- A unique case report

Oral cancer is the 6 commonest among all the malignancies, affecting more than half a million people each year, with a reported of 7500080000 new cases annually in India. Among other Head and Neck malignancies, 95% of cases accounts for oral squamous cell carcinomas. According to the surveillance, Epidemiology and End results program stated that the relative prognosis rate of 62.2% is given with an overall period of 5 years. Oral squamous cell carcinoma is before to specific potentially malignant disorders, of which the most common ones are Oral leukoplakia and OSMF due to a well-known risk factors like consumption of tobacco, arecanut and alcohol. Other factors include age and family history of cancer, HPV infections, immunosuppression, UV light and some hereditary associated conditions etc. According to WHO prognosticate by 2020, the tobacco-related deaths may exceeds 1.5 million per year. Several epidemiological studies showed that smokers tends to prosper oral cancer 5-9 times than non-smokers. This case report describes a well-differentiated oral squamous cell carcinoma involving the left lateral border of tongue.


Introduction
Cancer is the second leading cause of death globally after cardiovascular diseases and oral cancer is the third most common types of cancers affecting the mankind worldwide after lung and breast cancer. 1 The overall prevalence of oral cancer accounts for approximately 3% of all malignancies and estimated 2,70,000 people are annually attended. 2 The prevalence in south-east Asian countries like India is much higher than the worldwide prevalence. 3 The latest statistics see an increased incidence of oral cancers in India by a whopping 114% in the past six years 4 . The number of incident lip and oral cavity cancer cases in India in 2016 was 1,13,000 and the prevalent cases were 3,97,000. In India, the Lip and oral cavity cancer was the most common incident cancers in males with a maximum prevalence in the states of Madhya Pradesh, followed by Gujarat and kerala. 5 Most of the oral cancers (92-95%) comprises of oral squamous cell carcinomas. According to the International classification of diseases of the Head and neck malignancies, oral cancer is considered as a subgroup which may involves tongue, lips, salivary glands, gingiva, floor of the mouth, oropharynx, buccal surfaces and other intraoral locations, 6 commonly affecting the low income communities and in older individuals. Moreover, 90% of being in the over 45 years age group who are exposed to the known risk factors of tobacco and alcohol. Clinically, OSCC includes lip cancer, which accounts for the majority of OSCC and intraoral cancer which mainly affects the tongue. 7 OSCC within the mouth affects mainly the tongue, particularly the lateral borders of tongue, in older male individuals and are often related to lifestyle habits which are largely tobacco and alcohol related. 8 Several literatures stated that smoking and alcohol were considered as a major risk factors in 90% of cases, having them both a synergic affect. 9 The development of OSCC is considered as a complex multiple process, in which normal oral mucosal keratinocytes are chronically exposed to these risk factors may lead to the imbalance in homeostasis and generate genetic instability. 10 This case report presents a patient with a chronic nonhealing ulcer which turned out to be a well differentiated oral squamous cell carcinoma is discussed. He had the habit of both smoke and smokeless tobacco usage and alcohol.

Case Report
A 55 year old male patient visited with the chief complaint of an ulcer on the left side of tongue since 5 months. History of present illness revealed that the ulcer was associated with pain and mild burning sensation since 5 months, that gradually increased in intensity, aggrevating on taking spicy foods. No history of fever, trauma, loss of appetite. History revealed that he was a chronic smoker and had habit of alcohol consumption for the past 30 years and habit of pan chewing (gutkha) for the past 10 years. Patient referred to the tobacco cessation centre for counselling. During routine investigations, there was no relevant medical history. On extraoral examination, no facial asymmetry was observed. Solitary right and left submandibular lymph nodes were palpable of size 1x1cm, roughly oval in shape, tender, freely movable and firm in consistency. Level 2 lymph nodes palpable on left side, mildly tender and freely movable. On intraoral examination, blanching of labial mucosa and buccal mucosa with diffuse melanin pigmentation is seen. Restricted mouth opening of 25mm present. A solitary ulcero-infiltrative, erythematous lesion of size approximately 2.5 cm, roughly oval in shape seen on the left lateral border of the tongue extending anterioposteriorly from 2cm from the tip of the tongue and 3cm away from the posterior 1/3 rd of tongue. Superioinferiorly, extending from the dorsum of the tongue till 0.5 cm away from the floor of the mouth. Margins are raised. Floor of the ulcer anteriorly erythematous and posteriorly covered with yellowish pseudomembranous slough. No discharge is seen. Tongue shows restricted movements. On palpation, the lesion is tender and firm is consistency. Edges are raised and everted, base is indurated. Vertical fibrous bands are palpable on the right and left buccal mucosa along with the labial bands with leathery texture.

Discussion
The overall incidence and mortality attributed to the OSCC is increasing with current estimates of age standardized incidence and mortality of 6.6/100,000 and 3.1/100,000 in men and 2.9/100,000 and 1.4/100,000 in women. 11 The survival index continues to be 50% as compared to the progress in diagnosis and treatment of other malignant tumors. The early detection of precancerous and cancerous lesions to be improved for effective treatment and minimal morbidity. 12 The risk factors include tobacco associated intraoral carcinogens, which may play a synergistic role in oral tumorigenesis. 13 The other risk factors includes the alcohol consumption, low socio-economic conditions related to the poor oral hygienic, poor diet and rampant viral infections. 14 On the other hand, the molecular pathogenesis of OSCC is a multiple process. The genetic alterations observed in the head and neck cancers are mainly due to oncogenic activation and tumor suppression genes inactivation leading to de regulation of cell proliferation and death. 15 These genetic alterations include gene amplification and over expression of oncogenes such as myc, erb-2, epidermal growth factor receptor (EGFR), cyclinD1 and mutations, deletions and hypermethylation leading to p16 and p53 tumor suppressor gene inactivation. 16 The evaluation of the genomic stability can be done using technique such as a loss of heterozygosity (LOH) screening and comparative genomic hybridization (CGH). 17 In majority of cancers, highly vascularised tumors showed a poor prognosis and the influence of tumor angiogenesis proved to be independent of conventional prognostic indicators. 18 OSCC affecting tongue is most commonly of epithelial origin and may result from the chronic irritation. According to site, the tongue lesions constitues 34.6% with the lateral borders, being the most frequently affected site. 19 Well differentiated tumors has better prognostic value than poorly differentiated with a lower probability of lymph node metastasis. OSCC of the oral tongue is rare in young adults. Friedlander et al in a study of younger and older patients with tongue cancer matched for alcohol and tobacco usage. 20 Kurikose et al in their study comparing the tongue cancer in young and older OSCC patients in India concluded that in younger patients, OSCC of tongue was associated with few etiological factors and in older patents, it was always seen in association with smoking, alcohol and chewing. Metastastic spread of OSCC of tongue is facilitated by tongues rich lymphatic network, which tends to increase with the size of the primary tumor.
Lymphnode metastasis is a well known negative prognostic factor for OSCC of tongue and decreases the survival rate by 50%. Several studies have shown that the survival rate in men are lower than women with tongue cancer. The reported incidence of local recurrence rates in the margins ranged from 29%-70% and were 4%-38% for negative resection margins. 21

Conclusion
The poor prognosis of head and neck squamous cell carcinomas has intensified current research efforts in the field of prevention and early detection. The knowledge of analysing new genetic alterations will helpful for newer diagnostic and prognostic factors, which are helpful for rational and effective management of the patients.

Source of funding
None.