Tumor infiltrating neutrophil microabscess in OSCC: A poorly understood histopathologic prognosticator

Role of neutrophils in shaping the tumor microenvironment is well known in oral squamous cell carcinoma (OSCC). However, neutrophil microabscess (NM) formation within the tumor islands is distinctive phenomenon and has never been investigated in the literature. This pilot observational study identifies the incidence of NM in OSCC and its clinicopathologic correlation as a platform for the future studies.

A retrospective study was carried out on archival specimens of 121 cases of surgically excised OSCC specimens for identification of NM formations within the tumor islands using compound microscope. Mean NM density was calculated based on the quantification done at five randomly selected hotspots.

Out of total 121 cases of OSCC, thirteen (10.74%) cases showed a frank evidence of NM within tumor islands. The hotspot analysis showed that the NM density ranges from 2 to 7 with mean of 3.76 ± 1.39 per high power field. NM density was higher in moderately differentiated OSCC (3.76 ± 1.93) than well differentiated (3.76 ± 1.93) however the differences were not statistically significant (p = 0.165). Similarly, higher NM density was reported in advanced T stage, lymph node involvement, advanced TNM stage and lymphovascular invasion, however, the results were statistically insignificant.

There is evidence of NM formation in the tumor islands of OSCC, however their exact role as a prognosticator needs further exploration with large sample size and follow-up data.