Aim: To compare demographic, histopathological, and oncologic outcomes between small primary node-positive (pT1N+) and large primary node-negative (pT3/T4aN0) oral cavity squamous cell carcinomas (OCSCC). Methods: A retrospective cohort study was performed including patients diagnosed with pT1N+, pT3N0, and pT4aN0 OCSCC between 2017 and 2025. Demographic data included age, smoking, and alcohol status. Histopathological variables collected from final pathology reports included T and N stage, tumour subsite, maximum dimension, differentiation, margin status, depth of invasion (DOI), perineural invasion (PNI), lymphovascular invasion (LVI), worst pattern of invasion (WPOI), bone invasion, and dysplasia at surgical margins. Adjuvant therapy and outcomes including recurrence, second primary lesions, and overall survival were recorded. Results: A total of 134 cases were analysed (20 pT1N+, 25 pT3N0, 89 pT4aN0). No significant demographic differences were observed. Subsite distribution differed significantly (p<0.001): pT1N+ and pT3N0 tumours were predominantly oral tongue (60% and 76%), whereas pT4aN0 tumours most commonly involved the mandible (37.1%) and maxilla (29.2%). Differentiation and LVI were similar across groups. PNI, WPOI, bone invasion, and dysplasia at margins differed significantly. PNI was present in 5.3% of pT1N+ tumours compared with 36% and 32.6% of pT3N0 and pT4aN0 tumours, respectively. A non-cohesive invasive pattern (WPOI 4/5) was more frequent in node-positive tumours (80% vs 58.3%). Bone invasion was confined to pT4aN0 tumours (89.9%). Oncologic outcomes and adjuvant treatment did not differ significantly. Conclusion: pT1N+ tumours demonstrate distinct invasive characteristics despite small primary size, supporting the concept that nodal metastasis reflects tumour biology rather than tumour bulk alone. Tumour behaviour in OCSCC appears heterogeneous and not solely determined by T stage.