Table 21.

Histological classification

Histological classification	Cases (%)
Squamous cell carcinoma	4,329 (83.7%)
Squamous cell carcinoma	925 (17.9%)
Well differentiated	727 (14.1%)
Moderately differentiated	2075 (40.1%)
Poorly differentiated	602 (11.6%)
Adenocarcinoma	316 (6.1%)
Barrett's carcinoma	139 (2.7%)
Adenosquamous carcinoma	34 (0.7%)
Mucoepidermoid carcinoma	2 (0.0%)
Basaloid carcinoma	87 (1.7%)
Neuroendocrine tumor	1 (0.0%)
Neuroendocrine carcinoma	29 (0.6%)
Undifferentiated carcinoma	8 (0.2%)
Malignant melanoma	22 (0.4%)
Carcinosarcoma	25 (0.5%)
GIST	3 (0.1%)
Adenoid cystic carcinoma	4 (0.1%)
Sarcoma	3 (0.1%)
Other carcinomas	7 (0.1%)
Other tumors	33 (0.6%)
Unknown	130 (2.5%)
Total	5,172

GIST gastrointestinal stromal tumor