[Histopathological features of the lymph node metastases in patients with thoracic esophageal cancer]

Histopathological features of the lymph node involvement were studied in 104 patients with thoracic esophageal cancer who underwent subtotal esophagectomy combined with extended radical lymph adenectomy in cervicothoracoabdominal region. Metastatic involvement was found in a total number of 503 lymph nodes from 73 patients by histologic examination. The mean of long and short diameter was found to be less than 5mm in 125 (24.9%) of these 503 nodes. The involved area on the section was less than one third in 149 nodes (29.6%), and was significantly smaller in mediastinal lymph nodes than those in cervical or abdominal ones. Sixty-seven (13.3%) of 503 nodes were partially invaded by micrometastasis of 1mm or less in diameter. Micrometastasis also more frequently occurred in mediastinal nodes with a statistically significant difference. Extranodal proliferation (ENP) of cancer cells was found in 106 nodes (21.1%), and extranodal lymphatic and/or blood vessel invasion (ENly, v) was also recognized in 60 nodes (11.9%). Micrometastasis and ENP with or without ENly, v were found in 24 (32.9%) and 29 (39.7%) of 73 patients with positive lymph node metastasis, respectively. Postoperative survival rate in patients with micrometastasis and/or ENP with or without ENly, v was inferior to that in patients with neither of them.