Table 21.

Histological classification

Histological classification	Cases (%)
Squamous cell carcinoma	3300 (86.7 %)
Squamous cell carcinoma	685 (18.0 %)
Well differentiated	653 (17.2 %)
Moderately differentiated	1521 (40.0 %)
Poorly differentiated	441 (11.6 %)
Adenocarcinoma	222 (5.8 %)
Adenosquamous cell carcinoma	35 (0.9 %)
Adenoid cystic carcinoma	1 (0.0 %)
Basaloid carcinoma	56 (1.5 %)
Neuroendocrine cell carcinoma	17 (0.4 %)
Undifferentiated carcinoma	10 (0.3 %)
Other carcinoma	9 (0.2 %)
Carcinosarcoma	21 (0.6 %)
Malignant melanoma	11 (0.3 %)
GIST	1 (0.0 %)
Other	46 (1.2 %)
Unknown	78 (2.0 %)
Total	3807 (100 %)