Association of Perineural and Lymphovascular Invasion with Clinical and Pathological T Staging in Head and Neck Squamous Cell Carcinoma

Background/Objectives: Perineural invasion (PNI) and lymphovascular invasion (LVI) are adverse histopathological features in head and neck squamous cell carcinoma (HNSCC). Their relationship with clinical and pathological T categories remains clinically relevant, particularly in surgically treated cohorts. This exploratory retrospective study evaluated the frequency of PNI and LVI according to clinical and pathological T stage in primary HNSCC staged according to the AJCC/UICC 8th edition. Methods: We analyzed 170 consecutive surgically treated patients with primary HNSCC. PNI and LVI were recorded from histopathology reports of resection specimens. Results: PNI status was available in 124 cases and was positive in 61 (49.2%); LVI status was available in 126 cases and was positive in 62 (49.2%). PNI frequency increased with advancing clinical T stage (12.5% in cT1, 54.3% in cT2, 70.0% in cT3, and 69.2% in cT4) and pathological T stage (14.3% in pT1, 51.5% in pT2, 71.9% in pT3, and 66.7% in pT4). LVI also increased with higher clinical T stage (28.1%, 53.2%, 57.1%, and 61.5%) and pathological T stage (25.7%, 50.0%, 54.6%, and 75.0%). Tongue tumors showed descriptively high crude proportions of PNI and LVI, but these subgroup findings were based on small numbers and were not adjusted for T stage, depth of invasion, or other confounders. Conclusions: In this single-center cohort, PNI and LVI were more frequent in higher T categories. These findings should be interpreted as descriptive and hypothesis-generating, because no recurrence, survival, or treatment-outcome analyses were available and the adjusted models were exploratory.