Debating Deposits: An Interobserver Variability Study of Lymph Nodes and Pericolonic Tumor Deposits in Colonic Adenocarcinoma

Abstract

Context The AJCC 7th Ed defines pericolonic tumor deposits (TD) as discrete tumor foci in pericolic fat showing no evidence of residual lymph node (LN). This definition relies on subjective features rather than size (5th) or shape (6th) and introduced the category N1c. While typically straightforward, metastases are encountered where distinction between LN and TD is unclear. For data to be meaningful, agreement on distinguishing features between positive LN and TD is needed. Objective We evaluated the agreement between GI pathologists on difficult metastases and report a list of distinguishing features they found helpful. Design Tumor metastases (25) from right-sided colonic adenocarcinomas were selected where distinction between positive LN and TD was challenging. Virtual slides were reviewed by 7 GI pathologists. A list of features potentially helpful in differentiating positive LN and TD was ranked for usefulness by each pathologist. Every metastasis was diagnosed as positive LN or TD. For each case diagnosed as positive LN, reviewers listed every feature used in diagnosis. Results Complete agreement was found in 11/25 metastases, 5 positive LN and 6 TD (kappa statistic, 0.4; 95% CI, 0.28, 0.67). Top ranked features included round shape, peripheral lymphocyte rim, peripheral lymphoid follicles, possible subcapsular sinus, LN in surrounding fat and thick capsule. Top utilized features were similar. Conclusions Significant agreement between evaluators existed, but inconsistency remains. We found that round shape, lymphoid follicles, peripheral lymphocyte rim, LN in surrounding fat, possible subcapsular sinus and thick capsule were most often used to aid in LN diagnosis.

The Impact of Tumor Deposits on Colonic Adenocarcinoma AJCC TNM Staging and Outcome

“…Our data suggest that TD with no LN metastasis may behave similarly to positive LN, which supports the creation of the new category of N1c in 7 th edition since it would up-grade patients into stage III and likely result in additional chemotherapy. Since inter-observer variability exists, (19) some recent studies have proposed to classify TD as LN to decrease the subjectivity in assessments of TD. (17, 20)…”

Laparoscopy versus laparotomy for the management of endometrial carcinoma in morbidly obese patients: a prospective study

“…Tumor staging should be accurate. The interobserver variability can be seen among pathologists about the evaluation of positive lymph nodes and tumor deposits (17). In addition to interpathologist variations, BMI also influences the final lymph node count in EC staging (18).…”

Serosal surfaces, mucin pools, and deposits, Oh my: challenges in staging colorectal carcinoma

“…Since no definite criteria are provided to distinguish tumor deposits from totally replaced lymph nodes, the differential remains challenging in some cases where it is difficult to decide whether residual lymph node architecture exists. 37 Interobserver variability remains even when evaluated by pathologists with an interest in gastrointestinal pathology. 37 (Figure 10).…”

“…37 Interobserver variability remains even when evaluated by pathologists with an interest in gastrointestinal pathology. 37 (Figure 10). The helpful features of residual lymph node include round shape, peripheral lymphocytes/follicles, thick capsule, and possible subcapsular sinus.…”