The importance of stromal inflammation in squamous cell carcinoma of the tongue

BACKGROUND: Histological risk assessment evaluating worst pattern of tumour invasion (WPOI), and lymphocytic response (LR), has previously been shown to be of prognostic significance in squamous cell carcinomas of the head and neck (SCCHN). SCCHN is a heterogeneous group of tumours including tumours located in the oral cavity, of which the majority is located in the tongue. METHODS: Haematoxylin / eosin-stained slides from diagnostic biopsies from 94 cases of SCC on the tongue were evaluated for WPOI and LR. Within the inflammatory infiltrate, the percentage of eosinophilic granulocytes was also estimated. Results were correlated with clinical data such as response to treatment and recurrence. RESULTS: For WPOI the majority of patients, 84%, showed small invasive tumours islands with a size < 15 cells (grade 4). No correlation with survival, response to treatment or recurrence was seen for WPOI. More than half of the patients showed a dense lymphocytic infiltrate, a factor that was significantly correlated with complete response to radio therapy. Of the patients with dense lymphoid infiltrate, the majority, 63%, did not either have a recurrence. No significant correlation with recurrence, response to treatment or any other factor was seen for presence of eosinophils. CONCLUSIONS: Data clearly showed that tongue tumours have a split invasive growth pattern and an intense inflammatory response at the tumour interface. Results also indicated that evaluation of the intensity of the inflammatory infiltrate at the tumour interface in tongue SCC could provide information of potential importance for choice of treatment and prognosis. J Oral Pathol Med (2012) 41: 379-383