title: Morphological distribution of metastatic foci in sentinel lymph nodes with gastric cancer.
abstract: BACKGROUND
  The TNM classification defines micrometastasis (MM) and isolated tumor cells (ITC) in lymph nodes (LN). Sentinel node (SN) navigation surgery has been introduced in gastrointestinal cancer. Few reports have examined the morphological distribution of MM and ITC of SN in gastric cancer. The purpose of this study was to clarify the clinical significance of the morphological distribution of cancer cells in SNs according to metastasis (MA), MM, and ITC.
  
  
  METHODS
  All dissected LNs obtained from 160 consecutive patients with mapped SNs arising from cT1-2 N0 tumors were examined. Metastasis in these LNs was examined by histology and cytokeratin staining. The distribution of MA, MM, and ITC was classified as marginal sinus (MS), intermediate sinus (IS), parenchymal (PA), and diffuse types (DF).
  
  
  RESULTS
  Nodal metastases were detected in 65 SNs from 30 patients and MA, MM, and ITC accounted for 53.9%, 21.5%, and 24.6%, respectively. MS, IS, PA, and DF accounted for 57%, 6%, 17%, and 20.0%, respectively. Patients with metastasis of non-MS had more nodal metastasis in non-SNs (P = .025) and had nodal metastasis in second tier (P = .009), compared with the patients with metastasis of MS. The incidence of metastasis in non-MS was higher in tumors larger than 40 mm than those smaller than 40 mm (P = .011).
  
  
  CONCLUSIONS
  When performing SN navigation surgery in gastric cancer, we should keep in mind that the patients with tumor larger than 40 mm in size and nodal metastasis of non-MS may have non-SN metastasis and nodal metastasis in second tier.
authors.affiliation: Department of Surgical Oncology and Digestive Surgery, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan. y0810@m.kufm.kagoshima-u.ac.jp
authors.forename: Shigehiro
authors.initials: S
authors.lastname: Yanagita
authors.forename: Shoji
authors.initials: S
authors.lastname: Natsugoe
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Uenosono
authors.forename: Hideo
authors.initials: H
authors.lastname: Arima
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Kozono
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Ehi
authors.forename: Takaaki
authors.initials: T
authors.lastname: Arigami
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Higashi
authors.forename: Takashi
authors.initials: T
authors.lastname: Aikou
mesh_terms: D005260:Female; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D021701:Sentinel Lymph Node Biopsy; D013274:Stomach Neoplasms / Q000473:pathology*