Clinical course of diffuse invasive carcinoma of the tongue excised after Bleomycin treatment.

According to the mode of invasion across the tumour-host boundary which was described and graded by Jacobsson et al. (1973), the clinical course of diffuse invasive squamous cell carcinoma of the tongue (grade 4) was investigated comparing it with the other grade groups (grades 1-3). Metastasis to regional lymph nodes and local recurrence after surgery were extremely common in grade 4. These local recurrences led to death in most grade 4 cases while a better clinical outcome was achieved in the other grades. Grade 4 was further subclassified into a cord-like type (grade 4 C) and a diffuse type (grade 4 D) from the histological features of the tumour-host interface, with the latter being more malignant than the former.