title: Pulmonary lymphatic drainage to the mediastinum based on computed tomographic observations of the primary complex of pulmonary histoplasmosis.
abstract: BACKGROUND
  In the primary infection of pulmonary histoplasmosis, pulmonary lesions are commonly solitary and associated with hilar and/or mediastinal nodal diseases, which spontaneously resolve, resulting in calcifications in individuals with normal cellular immunity.
  
  
  OBJECTIVE
  To assess the lymphatic drainage to the mediastinum from each pulmonary segment and lobe using computed tomographic (CT) observations of a calcified primary complex pulmonary histoplasmosis and predict which patients with N2 disease that would benefit from surgery.
  
  
  METHODS
  We collected 585 CT studies of patients with primary complex histoplasmosis consisting of solitary calcified pulmonary lesions and calcified hilar and/or mediastinal nodal disease. Using the N stage criteria of non-small cell lung cancer, we assessed the distribution of the involved hilar and mediastinal nodes depending on the pulmonary segment of the lesion, with a focus on skip involvement. We also assessed the correlation between the incidence of N1 and skip N2 involvement and the mean number of involved mediastinal nodal stations in the non-skip N2 and skip N2 groups.
  
  
  RESULTS
  Skip involvement was common in the apical segment (9/45, 20.0%), posterior segment (7/31, 22.6%), and mediolbasal segment (13/20, 65.0%) in the right lung, and in the apicoposterior segment (7/55, 12.7%), lateral basal segment (6/26, 23.1%), and posterobasal segment (16/47, 34.0%) in the left lung. The incidence of skip involvement in each segment showed a significant inverse correlation with that of N1 involvement (r = -0.51, P <0.05) in both lungs. The mean number of involved mediastinal nodal stations in the non-skip N2 and skip N2 groups in all segments of both lungs were 1.4 (434/301) and 1.2 (93/77), and the former was significantly greater than the latter (P <0.01).
  
  
  CONCLUSIONS
  Our data showed a predictable pattern of segmental and lobar lymphatic drainage to the mediastinum and suggested that skip involvement could represent the initial mediastinal node involvement via direct lymphatic drainage.
authors.affiliation: Department of Radiology, Asahikawa Medical University and Hospital, Japan. taka1019@asahikawa-med.ac.jp
authors.forename: Koji
authors.initials: K
authors.lastname: Takahashi
authors.forename: Tomoaki
authors.initials: T
authors.lastname: Sasaki
authors.forename: Basim
authors.initials: B
authors.lastname: Nabaa
authors.forename: Edwin Junior
authors.initials: EJ
authors.lastname: van Beek
authors.forename: William
authors.initials: W
authors.lastname: Stanford
authors.forename: Tamio
authors.initials: T
authors.lastname: Aburano
mesh_terms: D002289:Carcinoma, Non-Small-Cell Lung / Q000150:complications / Q000000981:diagnostic imaging*; D004322:Drainage; D005260:Female; D006660:Histoplasmosis / Q000150:complications / Q000000981:diagnostic imaging*; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging; D008175:Lung Neoplasms / Q000150:complications / Q000000981:diagnostic imaging*; D008198:Lymph Nodes / Q000000981:diagnostic imaging; D008207:Lymphatic Metastasis; D008297:Male; D008482:Mediastinum / Q000000981:diagnostic imaging*; D008875:Middle Aged; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods*