Lymphadenectomy during Small Bowel Neuroendocrine Tumor Surgery: The Concept of Skip Metastases.
More than half of small bowel neuroendocrine tumors (SB-NETs) are metastatic at diagnosis, but complete resection of the primary tumor and lymph node (LN) is recommended by most authors. Our aim was to describe the pattern of involved LN after an extensive LN resection.



Between July 2013 and December 2015, all consecutive patients who underwent resection of at least one SB-NET in our European Neuroendocrine Tumor Society Center of Excellence were prospectively included, while patients with duodenal SB-NETs were excluded. The resection and pathological analysis of LNs were standardized using three groups (group 1, along the small intestine; group 2, along the mesenteric vessel; and group 3, retropancreatic and mesenteric vessel origin).



Twenty-eight patients with SB-NET resection were prospectively enrolled in the study, with seven patients being excluded from the analysis because it was impossible to divide the operative piece into nodal groups due to retractile mesenteritis. Among the remaining 21 patients, 20 (95 %) had LNs involved; 8 (38 %) in group 1, 13 (62 %) in group 2, and 12 (57 %) in group 3. Skip metastases were found in 14 patients (67 %): 4 (19 %) with an invasion pattern of group 3+ without group 2+, and 12 (57 %) with an invasion pattern of group 2+ or group 3+ without group 1+.



As a result of skip metastases, systematic, extensive LN resection in retropancreatic portion may be required to prevent unresectable locoregional recurrence.
Chirurgie Digestive, Hôpital Edouard Herriot, Hospices Civils de Lyon, 69437, Lyon Cedex 03, France. arnaud.pasquer@chu-lyon.fr.
Arnaud
A
Pasquer
Service de Gastroentérologie et d'Oncologie Digestive, Hôpital Edouard Herriot, Hospices Civils de Lyon, 69437, Lyon Cedex 03, France.|Faculté Laennec, Lyon Cancer Research Center, UMR 1052, INSERM, 69372, Lyon Cedex 08, France.|Université Claude Bernard Lyon 1, Université de Lyon, 69622, Villeurbanne Cedex, France.
Thomas
T
Walter
Université Claude Bernard Lyon 1, Université de Lyon, 69622, Villeurbanne Cedex, France.|Radiologie, Hôpital Edouard Herriot, Hospices Civils de Lyon, 69437, Lyon Cedex 03, France.
Pascal
P
Rousset
Faculté Laennec, Lyon Cancer Research Center, UMR 1052, INSERM, 69372, Lyon Cedex 08, France.|Université Claude Bernard Lyon 1, Université de Lyon, 69622, Villeurbanne Cedex, France.|Service Central d'Anatomie et Cytologie Pathologiques, Hôpital Edouard Herriot, Hospices Civils de Lyon, 69437, Lyon Cedex 03, France.
Valérie
V
Hervieu
Service de Gastroentérologie et d'Oncologie Digestive, Hôpital Edouard Herriot, Hospices Civils de Lyon, 69437, Lyon Cedex 03, France.
Julien
J
Forestier
Service de Gastroentérologie et d'Oncologie Digestive, Hôpital Edouard Herriot, Hospices Civils de Lyon, 69437, Lyon Cedex 03, France.
Catherine
C
Lombard-Bohas
Chirurgie Digestive, Hôpital Edouard Herriot, Hospices Civils de Lyon, 69437, Lyon Cedex 03, France.|Faculté Laennec, Lyon Cancer Research Center, UMR 1052, INSERM, 69372, Lyon Cedex 08, France.|Université Claude Bernard Lyon 1, Université de Lyon, 69622, Villeurbanne Cedex, France.
Gilles
G
Poncet
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D007078:Ileal Neoplasms / Q000473:pathology* / Q000601:surgery*; D007421:Intestine, Small; D007580:Jejunal Neoplasms / Q000473:pathology* / Q000601:surgery*; D008197:Lymph Node Excision; D008198:Lymph Nodes / Q000473:pathology* / Q000601:surgery; D008207:Lymphatic Metastasis; D008297:Male; D008638:Mesenteric Arteries; D008642:Mesenteric Veins; D008875:Middle Aged; D018358:Neuroendocrine Tumors / Q000601:surgery*; D010179:Pancreas; D011446:Prospective Studies