Is it possible to differentiate malignant mediastinal nodes from benign nodes by size? Reevaluation by CT, transesophageal echocardiography, and nodal specimen

Chest. 1996 Oct;110(4):1004-8. doi: 10.1378/chest.110.4.1004.


Study objective: To reevaluate whether it is possible to reliably differentiate malignant mediastinal lymph nodes from benign nodes by size, and to determine the frequency of metastases to normal-sized mediastinal lymph nodes that directly affects the sensitivity for detecting malignant mediastinal lymph nodes (N2 nodes) on CT.

Design: Prospective study of patients with non-small cell lung cancer.

Setting: Department of Radiology and First Department of Surgery, Yamaguchi University School of Medicine.

Patients: We examined 40 patients with non-small cell lung cancer, who underwent thoracotomy because of operable stage (stage I, II, IIIA) in preoperative staging, using CT and transesophageal echocardiography (TEE).

Interventions: None.

Measurements and results: Lymph nodes 10 mm or greater in short-axis diameter on CT and TEE were considered abnormal. Furthermore, lymph node size was measured by TEE and nodal specimens in long- and short-axis diameter in each patient. Two hundred eight mediastinal lymph nodes were dissected and N2 nodes were present in 28% of patients (11/40); in 7 of these 11 patients (64%), mediastinal lymph node metastases were misdiagnosed on CT because of normal-sized N2 nodes. Furthermore, in 73% of N2 nodes, nodal size was normal on TEE. There were no significant difference in both diameters between malignant mediastinal lymph nodes and benign nodes on TEE and nodal specimens.

Conclusions: It is not possible to reliably differentiate malignant mediastinal nodes from benign nodes by size alone, and we should be aware of high frequency of normal-sized N2 nodes in patients with operable stage of lung cancer.

MeSH terms

  • Adult
  • Aged
  • Biopsy
  • Carcinoma, Bronchogenic / diagnostic imaging
  • Carcinoma, Bronchogenic / pathology*
  • Carcinoma, Non-Small-Cell Lung / diagnostic imaging
  • Carcinoma, Non-Small-Cell Lung / pathology*
  • Echocardiography, Transesophageal
  • Female
  • Humans
  • Lung Neoplasms / diagnostic imaging
  • Lung Neoplasms / pathology*
  • Lymphatic Metastasis / diagnostic imaging
  • Lymphatic Metastasis / pathology*
  • Male
  • Mediastinal Neoplasms / diagnostic imaging
  • Mediastinal Neoplasms / secondary*
  • Middle Aged
  • Prospective Studies
  • Tomography, X-Ray Computed