MSI-H - sessile serrated polyp/adenoma as precursor lesion (more often right sided)
Distal, MSI-L / MSS - traditional serrated adenoma (more often left sided)
Based on: Jass JR. Histopathology 2007;50:113-130. MS: microsatellite; CIMP: CpG island methylator phenotype; TSA: traditional serrated adenoma Ex adenoma, TIL R>L F>M Neg MSI-H (HNPCC) Ex adenoma, dirty necrosis, tumor budding L>R M>F APC TP53 (KRAS) Neg MSS Ex villous adenoma (kras+) or serrated adenoma L>R M>F KRAS+ Low MSI- L or MSS Ex serrated polyps (TSA), serrated, mucinous, HG non-circumscribed, (TIL) R>L F>M BRAF+ High MSI- L or MSS Ex serrated polyps (sessile), serrated, mucinous , HG circumscribed, TIL R>L F>M BRAF+ High MSI-H (sporadic) Morphology Loc M / F Other CIMP MSI / MSS
Discontinuous spread, venous invasion (V1/2) -> TD ( pN1c, if no LN metastasis, for T1-2 tumors)
TD and V1 on the basis of the orcein (elastica) stain
The suggested number of LNs to be assessed for a reliable pN0
6 Hernanz F et al. Dis Colon Rectum 1994;37:373-6.
7 Caplin S et al. Cancer 1998;83:666-72. - Mainprize KS et al. J Clin Pathol 1998;51:165-6. - Cserni G. J Clin Pathol 2002;55:386-90.
8 Maurel J et al. Cancer 1998;82:1482-6.
9 Cianchi F et al. World J Surg 2002;26:384-9.
12 TNM Supplement 3rd Ed
13 Scott KWM et al. Br J Surg 1989;76:1165-7.
14 Wong JH et al. J Clin Oncol 1999;17:2896-900. - Tepper JE et al. J Clin Oncol 2001;19:157-63.
16 Cserni G et al. Pathol Oncol Res 1999;5:291-6.
17 Goldstein NS. Am J Surg Pathol 2002;26:179-89.
20 Greco P et al. Virchows Arch 2006;449:647-651.
How many LNs? As many as possible ! 8574 T3N0M0 CRC from the SEER database Cserni G, et al . Is there a minimum number of lymph nodes that should be histologically assessed for a reliable nodal staging of T3N0M0 colorectal carcinomas? J Surg Oncol 2002; 81:63-69.
Distance from the tumour as qualitative feature Cserni G, et al . Distance of lymph nodes from the tumor, an important feature in colorectal cancer specimens. Arch Pathol Lab Med 2001; 125:246-249. Tumour + 1-1 cm 2 cm 2 cm 3 cm 3 cm D C B A B C D 100 cases of CRC Mean: 17 LN / case
An example A B A B B C C C No fraction D in this specific case
Lymphatic mapping studies have demonstrated that direct drainage may occur from a tumor site to apical or even paraaortic LNs .
Merrie AE, et al. Dis Colon Rectum 2001; 44 :410-7.
T his LN proved to be the only positive LN resected with the colon, but was outside the margins of a standard right hemicolectomy , the operation usually performed for a primary carcinoma at the given location.
Ts i oulias GJ, et al. Arch Surg 2000; 135 :926-32.
Bilchik AJ, et al. J Clin Oncol 2001; 19 :1128-36.
The only positive (only CK+) / 18 LN Same 2 cases reported in 2 papers
Less success in other series (11-50 pts, mean 24 pts / series)
Median follow-up of 17 months 9 further cases were diagnosed with metachronous distant metastasis
S pecificity and sensitivity for predicting distant metastasis :
LN metastasis : 0.56 and 0.75 , respectively
O rcein detected VI : 0.39 and 1 , respectively
Elastic stains enable the detection of clinically relevant VI in greater frequency than HE stained histological slides. If nodal involvement is an indication for systemic chemotherapy , our data suggest that VI detected by the orcein stain should also be an indication for that .
Cserni G et al., JCP 2010;63(7):575-8.
Suspected VI in muscularis pr NOT VI! Unsuspected VI in submucosa VI!
Quirke's graded assessment of completeness of mesorectal excision (MRC trial) :
3-Good: Intact mesorectum with only minor irregularities of a smooth mesorectal surface. No defect is deeper then 5 mm. No coning on the specimen. Smooth CRM on slicing .
2-Moderate: moderate bulk to the mesorectum but irregularity of the mesorectal su r face. Moderate coning of the specimen towards the distal margin. At no site is the m.propria visible with the exception of the insertion of levator muscles. Moderate irregularity of CRM.
1-Poor: Little bulk to mesorectum with defects down onto m.propria and/or very irregular cir c umferential resection margin.