Completion Dissection or Observation for Sentinel-Node Metastasis in Melanoma.

BACKGROUND: Sentinel-lymph-node biopsy is associated with increased melanoma-specific survival (i.e., survival until death from melanoma) among patients with node-positive intermediate-thickness melanomas (1.2 to 3.5 mm). The value of completion lymph-node dissection for patients with sentinel-node metastases is not clear. METHODS: In an international trial, we randomly assigned patients with sentinel-node metastases detected by means of standard pathological assessment or a multimarker molecular assay to immediate completion lymph-node dissection (dissection group) or nodal observation with ultrasonography (observation group). The primary end point was melanoma-specific survival. Secondary end points included disease-free survival and the cumulative rate of nonsentinel-node metastasis. RESULTS: Immediate completion lymph-node dissection was not associated with increased melanoma-specific survival among 1934 patients with data that could be evaluated in an intention-to-treat analysis or among 1755 patients in the per-protocol analysis. In the per-protocol analysis, the mean (±SE) 3-year rate of melanoma-specific survival was similar in the dissection group and the observation group (86±1.3% and 86±1.2%, respectively; P=0.42 by the log-rank test) at a median follow-up of 43 months. The rate of disease-free survival was slightly higher in the dissection group than in the observation group (68±1.7% and 63±1.7%, respectively; P=0.05 by the log-rank test) at 3 years, based on an increased rate of disease control in the regional nodes at 3 years (92±1.0% vs. 77±1.5%; P<0.001 by the log-rank test); these results must be interpreted with caution. Nonsentinel-node metastases, identified in 11.5% of the patients in the dissection group, were a strong, independent prognostic factor for recurrence (hazard ratio, 1.78; P=0.005). Lymphedema was observed in 24.1% of the patients in the dissection group and in 6.3% of those in the observation group. CONCLUSIONS: Immediate completion lymph-node dissection increased the rate of regional disease control and provided prognostic information but did not increase melanoma-specific survival among patients with melanoma and sentinel-node metastases. (Funded by the National Cancer Institute and others; MSLT-II ClinicalTrials.gov number, NCT00297895 .).

Ciliated Hepatic Foregut Cyst: Definitive Diagnosis Is Critical to the Optimal Treatment Pathway.

Background. Ciliated hepatic foregut cyst (CHFC) is a rare, benign cyst of the liver, derived from the embryonic foregut epithelium. Although CHFCs are typically asymptomatic, some present with nonspecific abdominal symptoms. Imaging modalities alone are insufficient for diagnosis, with intrahepatic cholangiocarcinoma included in the differential due to nonspecific imaging features; definitive diagnosis relies on histologic confirmation. These lesions are often benign; however, larger lesions can have malignant transformation into squamous cell carcinoma (SCC), which carries a poor prognosis, thus making a definitive diagnosis, no matter what size, essential. Here, we present a case of CHFC as well as a comprehensive literature review. Given these data, we propose an algorithm for definitive diagnosis.

Neuroendocrine tumors of the rectum: a 10-year review of management.

Neuroendocrine tumors of the rectum constitute approximately 19 per cent of gastrointestinal neuroendocrine tumors (NETs). The histologic characteristics of the tumor seem to be an indicative prognostic factor. Optimal treatment of NETS of the rectum has been widely debated, but more recent studies suggest that treatment depends upon the size. The medical records of 37 patients with NETS of the rectum were retrospectively reviewed. We reviewed their presentation, surgical treatment, pathology, and outcome. All pathological specimens were reviewed. Neuroendocrine tumors of the rectum were classified as either well-differentiated tumors, well-differentiated neuroendocrine carcinoma, or poorly differentiated neuroendocrine carcinoma. Evaluating tumor size, we found 35/37 patients had tumors less than 1 cm, 1 patient had a tumor between 1 and 2 cm, and one had a tumor greater than 2 cm. Pathologic evaluation of the tumors revealed that 35 of the tumors invaded the submucosa only, one invaded the muscularis propria, and one invaded the perirectal adipose tissue. The histopathologic features of the tumors revealed that 34 of the tumors were well-differentiated NETS with benign features, one tumor had invaded the submucosa, with angioinvasion, and two tumors were neuroendocrine carcinoma. Thirty-five patients underwent local excision. Eleven had reexcisions for positive margins. Two patients had local excision for recurrence, and one patient underwent low anterior resection (4 cm). Twelve patients had negative margins, 25 had positive margins. Eleven patients underwent reexcision. Six had no evidence of residual disease, and five had persistent positive margins and were offered no further treatment. Nineteen patients had positive margins and did not have reexcision. They all had tumors < 1 cm. Despite half of the lesions being resected with final pathologic positive margins, we have seen no significant influence on recurrence or overall survival. This raises the question of margin clearance in early lesions.

GIST identified during bariatric surgery: to treat or not to treat?

BACKGROUND: Gastrointestinal stromal tumors (GIST) are rare GI tumors that compose 1% of GI tumors. With the rise in obesity, bariatric surgery is becoming an increasingly common procedure and the incidental GISTs in this population have been noted more often than in the general population. OBJECTIVE: We evaluated and characterized the incidental GISTs in our bariatric surgical population. SETTING: The study was completed at a Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program-accredited academic hospital system. METHODS: All GISTs identified during Roux-en-Y gastric bypass and laparoscopic sleeve gastrectomy between January 1, 2005 and December 31, 2016 were evaluated. Typical demographic, clinicopathologic, treatment, follow-up, and outcome data were recorded. RESULTS: Within the 2655 bariatric surgeries at our institution, 17 GISTs were identified (.64%). Mean age was 54 years; 94% of lesions were identified intraoperatively. Lesions were identified in the fundus (29.4%) or body (70.6%), were unifocal, and <1 cm; 94.1% of resections had clear margins. Histology revealed 88.2% spindle cell and 11.8% mixed histology with <5 mitoses/50 fields, portending a low malignancy potential. Follow-up included the bariatric surgeon and oncology consult; 17.6% were recommended by oncology for computed tomography surveillance. No recurrences were recorded. CONCLUSION: We present the largest cohort to date of incidental GISTs in a bariatric population. A diligent intraoperative examination of the serosa in the left-behind portion of the remnant in bypass and the discarded remnant in sleeves allows the bariatric surgeon the opportunity to leave the patient cancer-free after removal of incidental tumor.

Head and neck cancer PEG site metastases: Association with PEG placement method.

BACKGROUND: Many patients with head and neck cancer (HNC) will require feeding tube placement for nutritional support using percutaneous endoscopic gastrostomy (PEG) tube. Rarely, HNC metastases have been reported at the PEG site, a morbidity associated with a poor outcome. METHODS: Along with a case report, an evaluation of PEG placement methods with metastases from the literature was completed along with a statistical analysis of the literature to determine PEG site metastases and method of placement correlations. RESULTS: The incidence of PEG metastases in patients with HNC with the "pull" method is statistically identical to that of patients receiving any other method for PEG placement. CONCLUSIONS: When considering options for the placement of PEG tubes in patients with HNC, the "pull" method should not be considered as a technique which will put patients at risk for PEG site metastases more than any other method of placement.

Predictive genetic profiles for regional lymph node metastasis in primary cutaneous melanoma: a case-matched pilot study.

Melanoma confers an estimated lifetime risk of one in 50 for 2016. Clinicopathologic staging and sentinel lymph node biopsy (SLNB) have been the standard of care for T2 and T3 lesions. Molecular biomarkers identified in the primary lesion suggestive of metastatic potential may offer a more conclusive prognosis of these lesions. Our purpose was to investigate molecular mutations in primary melanoma that were predictive for micrometastasis as defined by a positive sentinel lymph node (SLN) in a case-controlled manner: nine patients with negative SLN and nine with positive SLN. The two cohorts were statistically identical as shown by a t-test for age (P=0.17), race (P=0.18), Breslow depth (P=0.14), Clark level (P=0.33), host response (P=0.17), ulceration (P=0.50), satellite nodules (P=0.17), lymphovascular invasion (P=0.50), and mitotic activity (P=0.09). While no single gene was significantly associated with SLN status, multivariate analysis using classification and regression tree assessment revealed two unique gene profiles that completely represented regional metastases in our cohort as defined by a positive SLN: PIK3CA (+) NRAS (-) and PIK3CA (-) ERBB4 (-) TP53 (+) SMAD4 (-). These profiles were identified in 89% of the patients with positive SLN; none of these profiles were identified in the SLN-negative cohort. We identified two unique gene profiles associated with positive SLN that do not overlap other studies and highlight the genetic complexity that portends the metastatic phenotype in cutaneous melanoma.

Differential expression of prognostic factors and effect on survival in young (< or =40) breast cancer patients: a case-control study.

The belief that young women develop more aggressive forms of breast cancer than other women is controversial. The purpose of this study was to determine if women 40 years of age and under with breast cancer have more negative prognostic indicators and a higher 5-year mortality than those women over 40 years of age. From January 1998-December 2002, all women with breast cancer were identified from our tumor registry. Women with metastatic disease at presentation were excluded from our study. The women were divided into two groups, women under 40 (cases) and women 40 and over (controls). Seventy-eight cases were identified and matched to 228 controls. These cohorts were matched 3:1 (cases:controls) based on tumor staging. The data collected on each patient included prognostic factors such as tumor size, tumor type, estrogen and progesterone receptors, Her2/neu, and Ki-67. Information on surgical procedure, postoperative therapy, recurrence, and mortality was also gathered. The mean ages for cases and controls were 35 and 59 years, respectively. The rates of modified radical mastectomy were similar in the two groups, but young women were more likely to have breast reconstruction (33.7% vs 9.8%). The rates of breast conservation therapy were actually lower in the group under 40 (32.5% vs 37.6%). Tumors in the 40 and under group were more frequently estrogen receptor negative (33.8% vs 21.9%: P = 0.046) and progesterone receptor negative (50.0% vs 35.5%: P = 0.033). Younger women also experienced a greater prevalence of Ki-67 (P < 0.001) and higher levels of Her2/neu overexpression (P = 0.013). Women over 40 were more likely to receive hormonal therapy (39.7% vs 36.1%). Women over 40 had a lower overall rate of recurrence. A difference in overall survival does exist between these two groups of women, which trends toward significance. The women 40 and under had a lower overall 5-year survival. The reason for this difference remains unclear. Although we demonstrate a higher percentage of younger women with negative biochemical markers, the only factors independently and significantly related to higher mortality were estrogen receptor negativity and tumor stage at presentation.

Treatment and outcomes of melanoma with a Breslow's depth greater than or equal to one millimeter in a regional teaching hospital.

Local control and regional lymph node evaluation are the primary treatment goals for cutaneous primary melanoma. Historically, primary lesions were excised with large 3- to 5-cm radial margins. Recent clinical trials have suggested that similar survival and recurrence rates can be achieved with smaller margins of excision. In addition to excision of the primary lesion, the presence or absence of nodal metastasis is the single most powerful predictor of survival in patients with melanoma. Based on the available trials, the standard of care for a melanoma 1 mm or greater in depth is a wide local excision with a 2-cm margin and a sentinel lymph node biopsy (SLNB). The application of this standard in regional teaching hospitals is unknown. We performed a retrospective review of a cancer registry at a teaching hospital in South Carolina. This analysis included all patients who underwent surgery for melanoma at our institution between July 1997 and March 2003. Our single inclusion criterion was that the primary melanoma had to be 1 mm or greater in depth. Only 42 per cent of the patients underwent excision with a radial margin >2 cm, and only 60 per cent of the patients underwent SLNB. As time progressed, the use of SLNB at our institution increased; but, even as late as 2003, some patients did not receive SLNB. Adherence to standards did not appear to have an effect on overall survival. In conclusion, the current standard for the treatment of invasive melanoma greater than or equal to 1 mm in thickness is a 2-cm margin of excision and a SLNB. In this regional teaching hospital, surgical treatment and staging of melanoma did not strictly adhere to the standard.

Management of periampullary adenocarcinoma by pancreaticoduodenectomy at a regional teaching hospital.

BACKGROUND: Periampullary adenocarcinoma (PA) includes: pancreatic, duodenal and ampullary adenocarcinoma; and cholangiocarcinoma. Pancreaticoduodenectomy (PD) is required for cure of PA. Previous studies demonstrated the likelihood of cure increases when a microscopically negative (R0) margin is achieved. Clearance of the superior mesenteric artery (SMA) margin has been identified as the most critical margin in PD. Some authors have emphasized the importance of certain techniques to clear the SMA margin. Neither the degree to which these techniques have been incorporated nor their impact on margin status and survival has been described. We hypothesized that use of techniques focusing on clearing the SMA margin would result in higher R0 resection rates and improved survival after PD in patients with PA. METHODS: A retrospective study was performed on patients from 1/1/1985 until 7/31/2007. Data on patient demographics, clinical presentation, preoperative treatment, operative technique, margins, and postoperative outcomes were collected. Ninety-three patients were identified for inclusion in the study. Three approximately equal groups were created for analysis. RESULTS: The overall survival (OS) for the entire cohort was 19 months and was not different among the groups studied. Margins were microscopically negative in 81% of cases. The percentage of node-positive cases increased during the time period, as did the number of lymph nodes (LNs) examined (P=0.017). The use of pylorus-preserving PD decreased (P=0.001) while resection of the superior mesenteric/portal vein (SMV/PV) increased during the study period. We observed an increase in descriptions of the clearance of the anterior aspect of the aorta and inferior vena cava (IVC), dissection to the right side of the SMA, dissection to the origin of the SMA and intra-operative identification of the SMA margin. Dissecting to the SMA did not change the likelihood of achieving an R0 margin. OS was improved after R0 resections (R0: 21 months vs. R1/2: 10 months) but this difference was not statistically significant (P=0.099). There was no association between margin status and OS. Changes in the pathology reporting of margins were observed, with statistically significant increases in the percentage of cases in which the SMA, common bile duct and pancreatic neck margins were separately reported. However, the SMA margin was separately reported in only 26% of pathology reports. CONCLUSIONS: The operative techniques used in PD at this institution have changed over time. The increasing frequency of dissection to the SMA and identification of the SMA margin by both surgeon and pathologist suggest an increased attention to the SMA margin. This shift did not result in significant improvements in survival or margin status, but it is consistent with the recognition of the importance of the SMA margin. Our analysis has also identified areas of potential improvement in the ways in which operative and pathology reports for PD are generated.

Sentinel node in the era of neoadjuvant therapy and locally advanced breast cancer.

The most important determinant of prognosis for patients with breast cancer is the status of the axillary lymph nodes. Axillary lymph node dissection (ALND) has been performed for over a century to stage the cancer, achieve regional control, and perhaps improve survival. In accordance with tradition, ALND has been performed on all patients with the diagnosis of invasive breast cancer. In the early 1990s, this dogma was challenged because of the significant morbidity associated with ALND (paresthesia, extremity lymphedema) and the fact that greater than 50% of all breast cancers are node negative. A less morbid but highly accurate staging procedure, lymphatic mapping and sentinel lymph node biopsy (SNB) was introduced. Currently, the de facto standard of care in breast cancer is to perform LM and SNB in patients with small tumors and clinically negative axilla. While numerous methodological issues are being raised, the utility of LM and SNB identification continues to expand. In the current review we assess the application of this technique to locally advanced breast cancer (LABC) and neoadjuvant chemotherapy. What role does SNB play in locally advanced disease? Is LM and SNB accurate for patients with advanced disease? What influence do axillary metastases have on further treatment? What is the role of SNB in the planning for neoadjuvant patients? The skillful management of patients with breast cancer lies in the delicate balance between maximizing the efficacy of treatment and minimizing its morbidity and failure.

Combination probe and dye-directed lymphatic mapping detects micrometastases in early colorectal cancer.

Nodal metastasis is the single most important prognostic factor in early colorectal cancer (CRC). Lymphatic mapping can identify sentinel nodes for focused histopathologic examination and thereby improve the nodal staging of CRC; however, the optimal technique for identifying sentinel nodes in CRC is unclear. We hypothesized that a combination of radiotracer and blue dye would more accurately identify tumor-positive sentinel nodes than blue dye alone. Lymphatic mapping was performed in 48 consecutive patients undergoing resection for CRC and in two original patients who underwent sentinel node mapping in 1996. Prior to resection, 1% vital blue dye and radiotracer were injected around the tumor in the subserosal layer. Nodes were designated as sentinel by blue coloration and/or radioactivity. Lymphatic mapping identified at least one sentinel node in 49 patients. Focused examination of multiple sentinel node sections by means of hematoxylin and eosin and immunohistochemical analysis showed that sentinel nodes accurately predicted the status of the nodal basin in 93.8% (46 of 49) of patients. Of the 19 patients with nodal metastases, 11 had macrometastases (>.2 mm), three had micrometastases (between 2 mm and 0.2 mm), and five had isolated tumor cells or clusters (<.2 mm) identified by immunohistochemical analysis only. Patients had significantly fewer blue/radioactive ("hot") nodes than blue-only nodes (1.38 vs. 2.48 per patient; P = 0.0001). It is important to note that nodal metastases were more common in blue/hot nodes than in blue-only nodes (27.3% [19 of 68] vs. 8.8% [11 of 124]; P = 0.005). Dual-agent lymphatic mapping more accurately identifies sentinel node metastases than blue dye alone. In addition, this technique allows a more focused histopathologic examination of these nodes, in conjunction with the revised American Joint Committee on Cancer guidelines, and thereby offers the potential for significant upstaging of CRC.

Identification of an occludin cell adhesion recognition sequence.

The molecular mechanisms by which the tight junction integral membrane protein, occludin promotes cell adhesion and establishes an endothelial monolayer permeability barrier have not been elucidated. In particular, the amino acid sequences of the occludin cell adhesion recognition (CAR) sites have not been determined. Here we demonstrate that a cyclic peptide containing the sequence LYHY, which is found in the second extracellular domain of occludins in all mammalian species, inhibits the establishment of endothelial cell barriers in vitro and in vivo. This cyclic peptide also prevents the aggregation of fibroblasts stably transfected with cDNA encoding occludin. The data suggest that the LYHY motif is an occludin CAR sequence.

Differential expression of thymidylate synthase in colorectal tumors and matched lymph nodes: impact on adjuvant treatment.

Although the expression of thymidylate synthase (TS) in metastatic colorectal cancer (CRC) may be a better predictor of response to 5-fluorouracil chemotherapy than TS expression in primary CRC, this enzyme has not been well studied in tumor-draining regional lymph nodes. We retrospectively examined TS expression in 12 primary CRC lesions (pT3) and matched sentinel lymph nodes. Of the 8 primary tumors that were TS-positive, 50 per cent (4/8) had tumor-positive lymph nodes and 50 per cent (4/8) had tumor-negative nodes. Of the 4 primary tumors that were TS-negative, 75 per cent (3/4) had tumor-positive nodes and 25 per cent (1/4) had tumor-negative nodes [kappa = -0.1386, 95 per cent confidence interval: (-0.4820, 0.2048), P = 0.4284]. Of the 8 TS-positive primaries, 25 per cent (2/8) had TS-positive nodes and 75 per cent (6/8) had TS-negative nodes. Of the 4 TS-negative primaries, 50 per cent (2/4) had TS-positive nodes and 50 per cent (2/4) had TS-negative nodes [kappa = -0.0131, 95 per cent confidence interval: (-0.2958, 0.2696), P = 0.9274]. Two of the three TS-negative primaries that had metastasized to regional lymph nodes were associated with TS-positive lymph nodes. Our findings indicate that expression of TS by a primary CRC does not correlate with nodal metastases or nodal TS expression. Nodal expression of TS may be important in predicting response to 5-fluorouracil when a primary CRC is TS-negative.

Videoscopic inguinal lymphadenectomy in malignant melanoma: safe in pregnancy?

Lymphadenectomy is the standard of care for metastatic melanoma in the inguinal lymph node basin. Historically, open surgery was the only treatment option. However, in recent years, videoscopic inguinal lymphadenectomy (VIL) has become a popular approach as it offers a minimally invasive alternative, provides similar oncologic control and reduces wound complications. Even though the VIL approach is being used more frequently, the patient populations that stand to benefit the most from this approach are still under investigation. Despite continued advances in safety for laparoscopic surgery, many surgeons are hesitant to perform these procedures on pregnant women. In this report, we present a successful VIL in a pregnant patient, describe our technique and demonstrate the safety of performing VIL in expectant mothers. To our knowledge, this case represents the first VIL performed in an expectant mother.

Differential lymph node retrieval in rectal cancer: associated factors and effect on survival.

BACKGROUND: Recent publications have identified positive associations between numbers of lymph nodes pathologically examined and five-year overall survival (5-yr OS) in colon cancer. However, focused examinations of relationships between survival of rectal cancer and lymph node counts are less common. We conducted a single institution, retrospective review of rectal cancer resections to determine whether lymph node counts correlated with 5-yr OS and to explore the relationship between lymph node counts and various clinical and pathologic factors. METHODS: A retrospective review of our institutional tumor registry identified 159 patients with AJCC Stage 1, 2, or 3 rectal cancers that underwent surgical resection at our institution over eleven years. Univariate analysis was used to explore the relationship between lymph node counts and age, AJCC Stage, time period of diagnosis, preoperative radiotherapy, and performance of TME. Survival analysis was performed by the Kaplan-Meier method and the Cox proportional hazards model. RESULTS: In univariate analysis, there was an association between increased lymph node counts and age <70, higher stage, and diagnosis during the later portion of the study period [all P-values <0.05]. Lymph node counts were not associated with survival in Kaplan-Meier analysis or in multivariate Cox proportional hazards analysis. CONCLUSIONS: Increasing lymph node counts improve survival and the accuracy of colorectal cancer staging. The body of literature recommends identical minimum lymph node counts in both colon and rectal cancer. In our study, which exclusively examined rectal cancer, we could not demonstrate that increased lymph node counts were associated with improved survival.

Lymphatic mapping and sentinel node analysis to optimize laparoscopic resection and staging of colorectal cancer: an update.

BACKGROUND: Laparoscopic colectomy for colorectal cancer (CRC) has been criticized because of the potential for inadequate nodal dissection and incomplete staging. Lymphatic mapping (LM) and sentinel lymph node (SLN) analysis can improve the accuracy of staging in open colectomy, but its utility during laparoscopic colectomy is unknown. METHODS: Between 1996 and 2002, 30 patients with clinically localized colorectal neoplasms or premalignant polyps underwent subserosal or submucosal injection of isosulfan blue dye via a colonoscope, via a percutaneously inserted spinal needle, or through a hand port. Blue-stained lymphatics were visualized through the laparoscope and followed to the SLN, which was tagged. The colectomy was completed in standard fashion. All lymph nodes were stained by hematoxylin and eosin, and multiple sections of each SLN were examined by immunohistochemical (IHC) staining using cytokeratin antibody. RESULTS: An SLN was identified laparoscopically in all patients. The SLN accurately predicted the tumor status of the nodal basin in 93% of cases. In 8 cases (29%), an unexpected lymphatic drainage pattern altered the extent of mesenteric resection, and in 4 cases (14%), tumor deposits were identified only by IHC and limited to the SLN. CONCLUSIONS: This study, which updates a preliminary report (Am Surg. 2002;68:561-565) confirms that SLN mapping during laparoscopic colon resection can alter the margins of resection and may improve staging by allowing a focused pathologic examination of the SLN, although direct comparison with the "gold standard" of open CRC with adequate lymphadenectomy will be required. Better ultrastaging of CRC lymph nodes may more accurately assign patients to prospective protocols to assess the significance of nodal micrometastases or isolated tumor cells.

Colorectal carcinoma nodal staging. Frequency and nature of cytokeratin-positive cells in sentinel and nonsentinel lymph nodes.

CONTEXT: Nodal staging accuracy is important for prognosis and selection of patients for chemotherapy. Sentinel lymph node (SLN) mapping improves staging accuracy in breast cancer and melanoma and is being investigated for colorectal carcinoma. OBJECTIVE: To assess pathologic aspects of SLN staging for colon cancer. DESIGN: Sentinel lymph nodes were identified with a dual surgeon-pathologist technique in 51 colorectal carcinomas and 12 adenomas. The frequency of cytokeratin (CK)-positive cells in mesenteric lymph nodes, both SLN and non-SLN, was determined along with their immunohistochemical characteristics. RESULTS: The median number of SLNs was 3; the median number of total nodes was 14. The CK-positive cell clusters were detected in the SLNs of 10 (29%) of 34 SLN-negative patients. Adjusted per patient, SLNs were significantly more likely to contain CK-positive cells than non-SLNs (P <.001). Cell clusters, cytologic atypia, and/or coexpression of tumor and epithelial markers p53 and E-cadherin were supportive of carcinoma cells. Single CK-positive cells only, however, could not be definitively characterized as isolated tumor cells; these cells generally lacked malignant cytologic features and coexpression of tumor and epithelial markers and in 2 cases represented mesothelial cells with calretinin immunoreactivity. Colorectal adenomas were associated with a rare SLN CK-positive cell in 1 (8%) of 12 cases. CONCLUSIONS: Sentinel lymph node staging with CK-immunohistochemical analysis for colorectal carcinomas is highly sensitive for detection of nodal tumor cells. Cohesive cell clusters can be reliably reported as isolated tumor cells. Single CK-positive cells should be interpreted with caution, because they may occasionally represent benign epithelial or mesothelial cells.