[Squamous cell carcinoma of the trachea: imaging lymph node mapping]

The anatomy of the trachea lymphatics is poorly understood and the only researches date back to more than one century. Tracheal tumors are very rare, miscellaneous and variously lymphophilic. The cancers of the trachea have no TNM and their lymph node metastases are little studied despite their poor prognosis. We observed 2 cases of squamous cell carcinoma, one in the cervical and the other in the intrathoracic trachea. TDM-3D reformats demonstrated metastatic lymph nodes of the right para-tracheal lymph node chain (2R and 4R) in both patients and in the cervical lymph nodes (right recurrent nerve lymph node chain) in the patient with cervical tumor. Right location of the mediastinal metastases may be explained by the anatomy of the lymph node chain drainage of the lung segments, the right para-tracheal chain being the only one to regularly possess lymph nodes at that level. The right recurrent nerve lymph node metastases of the cervical tumor are explained by common lymph drainage of the cervical trachea towards larynx lymph centres. Besides lymph node metastases, cancers prognosis may also depends on its location in the trachea. Thus, the tracheal tumors are complex and constitute quite as many orphan tumors. Multicentric studies are mandatory to better understand their behavior. Means provided by new imaging techniques might permit establishing a veritable TNM lymph node mapping of these tumors.