The assessment of lymph nodes missed in mesenteric tissue after standard dissection of colorectal cancer specimens.
OBJECTIVE
We studied fresh mesenteric and mesorectal tissue after standard dissection of colorectal cancer specimens using a clearing method to evaluate lymph nodes (LN) that could have been missed.


METHODS
After traditional dissection, 50 consecutive unfixed residual mesenteric and mesorectal tissues were entirely managed by a new clearing solution, which incorporates hydrochloric acid obtaining a really good degree of fat dissolution, facilitating the identification of missed LNs.


RESULTS
By fat clearance, 498 (mean per specimen, 10) additional LNs were found, most of them (83%) varying in size from 1 to 5 mm. and 22 (4.41%) LNs revealed tumour metastases. In two rectal carcinoma specimens that had been treated by neoadjuvant chemoradiotherapy, no LNs were found by traditional dissection; after checking by the clearing method, additional LNs were harvested in both. Three patients were reclassified and upstaged.


CONCLUSIONS
According to our findings, after standard dissection in the remaining mesentery of colorectal specimen there are missed positive LNs, which should be evaluated to avoid pathological understaging.
Hernanz
F
F
Department of Surgery, Faculty of Medicine, University Hospital Marqués de Valdecilla, Cantabria University, Santander, Spain. cgdhff@humv.es
García-Somacarrera
E
E
Fernández
F
F
D003082:Colectomy / Q000379:methods*; D015179:Colorectal Neoplasms / Q000175:diagnosis / Q000556:secondary* / Q000601:surgery; D006801:Humans; D008197:Lymph Node Excision / Q000379:methods*; D008198:Lymph Nodes / Q000473:pathology* / Q000601:surgery; D008207:Lymphatic Metastasis; D008643:Mesentery; D009367:Neoplasm Staging