Not all “mucinous carcinomas” are equal: time to redefine and reinvestigate the biologic significance of mucin types and patterns in the GI tract

Comparison of clinicopathological characteristics and survival outcomes between gallbladder mucinous adenocarcinoma and gallbladder adenocarcinoma: A propensity score-matched study

BACKGROUND

Gallbladder mucinous adenocarcinoma (GBMAC) is a rare subtype of gallbladder adenocarcinoma (GBAC), with limited knowledge of its survival outcomes from small case series and single-center retrospective analysis.

AIM

To compare the clinicopathological characteristics of GBMAC with typical GBAC and its prognostic factors to gain insights into this field.

METHODS

This study was conducted using data from the Surveillance, Epidemiology, and End Results database, including cases of GBMAC and typical GBAC diagnosed from 2010 to 2017. The Pearson chi-square test or Fisher exact test was used to examine the differences in clinicopathological features between these two cohorts. In addition, propensity score matching (PSM) analysis was performed to balance the selection biases. Univariate and multivariate Cox hazards regression analyses were performed to determine independent prognostic factors for cancer-specific survival (CSS) and overall survival (OS). The Kaplan-Meier curves and log-rank tests were used to assess the OS and CSS of GBMAC and typical GBAC patients.

RESULTS

The clinicopathological and demographic characteristics of GBMAC were different from typical GBAC. They included a larger proportion of patients with unmarried status, advanced American Joint Committee on Cancer (AJCC) stage, higher T stage, higher N1 stage rate and lower N0 and N2 stage rates (P < 0.05). Multivariate analyses demonstrated that surgery [OS: Hazard ratio (HR) = 2.27, P = 0.0037; CSS: HR = 2.05, P = 0.0151], chemotherapy (OS: HR = 6.41, P < 0.001; CSS: HR = 5.24, P < 0.001) and advanced AJCC stage (OS: Stage IV: HR = 28.99, P = 0.0046; CSS: Stage III: HR = 12.31, P = 0.015; stage IV: HR = 32.69, P = 0.0015) were independent prognostic indicators for OS and CSS of GBMAC patients. Furthermore, after PSM analysis, there was no significant difference between GBMAC and matched typical GBAC patients regarding OS (P = 0.82) and CSS (P = 0.69).

CONCLUSION

The biological behaviors of GBMAC are aggressive and significantly different from that of typical GBAC. However, they show similar survival prognoses. Surgery, chemotherapy, and lower AJCC stage were associated with better survival outcomes. Further research is needed in the future to verify these results.

Frequency and clinicopathologic associations of DNA mismatch repair protein deficiency in ampullary carcinoma: Routine testing is indicated

BACKGROUND

The significance of DNA mismatch repair (MMR) deficiency in ampullary cancers (ACs) has not been established.

METHODS

In total, 127 ACs with invasive carcinomas measuring ≥3 mmthat had adequate tissue were analyzed immunohistochemically.

RESULTS

MMR loss was detected in 18% of ACs (higher than in colorectal cancers). Twelve tumors with MLH1-PMS2 loss were negative for BRAF V600E mutation, suggesting a Lynch syndrome association. MMR-deficient tumors (n = 23), comparedwith MMR-intact tumors (n = 104), showed a striking male predominance (male:female ratio, 4.7). Although the deficient tumors had slightly larger invasion size (2.7 vs 2.1 cm), they also had more expansile growth and less invasiveness, including less perineural invasion, and they ultimately had lower tumor (T) classification and less lymph node metastasis (30% vs 53%; P = .04). More important, patients who had MMR-deficient tumors had better clinical outcomes, with a 5-year overall survival rate of 68% versus 45% (P = .03), which was even more pronounced in those who had higher Tclassification (5-year overall survival, 69% vs 34%; P = .04). MMR deficiencyhad a statistically significant association with medullary phenotype, pushing-border invasion, and tumor-infiltrating immune cells, and it occurred more frequently in ampullary-duodenal type tumors. Programed cell death-ligand 1 (PD-L1) levels analyzed in the 22 MMR-deficient ACs revealed that all medullary carcinomas were positive. Nonmedullary MMR-deficient carcinomas expressed PD-L1 in 33% of tumors cells according to the criteria for a combined positive score ≥1, but all were negative according to the tumor proportion score≥1 method.

CONCLUSIONS

In ACs, MMR deficiency is even more frequent (18%) than in colon cancer and often has a Lynch-suggestive profile, thus routine testing is warranted. Male gender, pushing-border infiltration, ampullary-duodenal origin, medullary histology, and tumor-related inflammation have a significantly higher association with MMR deficiency. MMR-deficient tumors have less aggressive behavior. PD-L1 expression is common in medullary-phenotype ACs, thus immunotherapy should be considered at least for this group.

Pathological aspects of mucinous cholangiocarcinoma: A single-center experience and systematic review

Cholangiocarcinoma is a malignant neoplasm originating from the biliary epithelium. Its incidence is highest in Southeast Asia, especially in Thailand. Mucinous intrahepatic cholangiocarcinoma (mucinous iCCA), characterized by an abundant extracellular mucin pool accounting for at least 50% of total tumor volume, is an extremely rare variant of such malignancy and is notorious for rapid progression and dismal prognosis. We conducted an 11-year retrospective analysis of resected mucinous iCCAs from our institution with a systematic review on mucinous iCCAs and combined hepatocellular-mucinous cholangiocarcinoma (cHCC-mCCA). There were four resected mucinous iCCA specimens at our institution (prevalence = 0.5%). Most of the patients were male. The clinicopathological characteristics were variable. The diagnosis of mucinous iCCAs could not be rendered without pathological evaluation. Either intraductal papillary neoplasm or biliary intraepithelial neoplasia was present in three out of four cases. One patient passed away at 11 months following liver resection. A total of 19 mucinous iCCAs and four cHCC-mCCAs from previously published literature were analyzed. The 1-year mortality rate of mucinous iCCAs from our series and published literature is 35%. The present study confirmed that mucinous iCCA is an exceedingly uncommon variant of iCCA. The differential diagnoses include metastatic carcinoma with mucinous component and cHCC-mCCA.

Mucinous intrahepatic cholangiocarcinoma: a distinct variant

Mucinous variant of intrahepatic cholangiocarcinoma (iCC) is rare, and its clinicopathological features and prognosis are far less clear. Six patients who had iCCs with more than 50% of mucinous component and 79 conventional iCCs were included in the study. The mean size of mucinous and conventional iCCs was 6.2 and 6.0 cm, respectively. Most patients (83%) with mucinous iCC presented at T3 stage or above compared with 28% of the conventional group (P < .01). Three patients with mucinous iCC (50%) died within 1 year. The average survival time of patients with mucinous iCCs was significantly reduced compared with that of the conventional group (9 months versus 2 years; P < .001). Immunohistochemistry was performed on 6 mucinous and 12 conventional iCCs with matched age, sex, and stage, which revealed positive immunoreactivity in MUC1 (83% versus 58%), MUC2 (33% versus 17%), MUC5AC (100% versus 42%), MUC6 (50% versus 0), CK7 (83% versus 83%), CK20 (0 versus 17%), CDX2 (17% versus 0), p53 (67% versus 67%), Smad4 (67% versus 58%), and EGFR (83% versus 42%) in mucinous and conventional iCCs, respectively. Molecular studies showed one mucinous iCC with KRAS G12C mutation and no BRAF or IDH1/2 mutations. Mucinous iCC is a unique variant that constitutes 7% of iCCs. It is more immunoreactive for MUC1, MUC2, MUC5AC, and MUC6. Unlike adenocarcinomas of colorectal primary, mucinous iCCs are often CK7+/CK20-/CDX2- and microsatellite stable. Patients with mucinous iCC likely present at advanced stage upon diagnosis with shorter survival time compared with the conventional counterparts.

Prevalence of local recurrence of colorectal cancer at the Iranian Cancer Institute

BACKGROUND

Although a great deal of progress has been made in the management of colorectal cancer in terms of neoadjuvant modalities, surgical techniques and adjuvant therapies, the recurrence of tumors remains an enigmatic complication in patients. A better understanding of colorectal cancer and of factors that lead to recurrence of disease can provide helpful information for designing more effective screening and surveillance methods.

AIM

To investigate the factors that may lead to local recurrence of colorectal cancers.

MATERIALS AND METHODS

The current retrospective case study evaluated 617 patients admitted to the Iranian Cancer Institute (the largest referral cancer center in the country) from 1995 to 2009 with confirmed colorectal cancer. Patients with distant metastasis, or with pathology other than adenocarcinoma and no follow-up, were excluded (175 patients). The remainder (442) included 294 (66.5%) with rectal cancer and 148 (33.5%) with colon cancer. The median duration of follow-up was 26 months.

RESULTS

The total rate of recurrence was 17.4%, comprising 19.6% and 16.3% recurrence rates in colon and rectal cancer, respectively.

CONCLUSIONS

Recurrence of colorectal cancer was significantly correlated to tumor grade (p<0.008).

Mucinous carcinomas of the gallbladder: clinicopathologic analysis of 15 cases identified in 606 carcinomas

CONTEXT

There are virtually no data in the literature regarding the incidence, patterns, and clinicopathologic characteristics of mucinous carcinomas (MCs) of the gallbladder (GB).

OBJECTIVE

To determine the incidence of mucinous differentiation in invasive GB carcinomas and the clinicopathologic characteristics of those that qualify as MC.

DESIGN

Primary invasive GB carcinomas (n  =  606) were reviewed for mucinous differentiation. Some degree of mucin production was identified in 40 cases (6.6%); however, only 15 (2.5%) were qualified for the World Health Organization definition of MC (stromal mucin deposition constituting >50% of the tumor).

RESULTS

The mean age was 65 years, and the female to male ratio was 1.1 (versus 3.9 for conventional pancreatobiliary-type GB adenocarcinomas; P  =  .04). A significant proportion of the cases (8 of 12, 67%) presented with the clinical picture and intraoperative findings that were interpreted as acute cholecystitis. Mean and median tumor sizes were larger than those of conventional adenocarcinomas (4.8 and 3.4 cm versus 2.9 and 2.5 cm, respectively; P  =  .01). Most (13 of 15, 87%) cases presented with pT3 tumors (versus 48% for ordinary GB carcinomas; P  =  .01). Two cases had almost an exclusive colloid pattern (>90% composed of well-defined stromal mucin nodules that contained scanty carcinoma cells, most of which were floating within the mucin). Eight cases were of mixed-mucinous type, showing a mixture of colloid and noncolloid patterns. Five others had prominent signet-ring cells, both floating within the mucin (which constituted >50% of the tumor by definition) and infiltrating into the stroma as individual signet-ring cells in some areas. Immunohistochemical analysis performed on the 7 cases that had available tissue revealed CK7 in 4 of 7 (57%), CK20 in 2 of 7 (29%), MUC1 in 4 of 7 (57%), MUC2 in 6 of 7 (86%), CDX2 in 1 of 7 (14%), MUC5AC in 6 of 7 (86%), MUC6 in 0 of 7 (0%), and loss of E-cadherin in 6 of 7 (86%). The MLH1 and MSH2 were retained in 6 of 7 cases (100%). Follow-up information was available for 13 cases: 11 (85%) died of disease (1-37 months) and 2 (15%) were alive (23 months and 1 month). Overall survival of MCs was significantly worse than that of conventional adenocarcinomas (13 versus 26 months; P  =  .01); however, that did not seem to be independent of stage.

CONCLUSIONS

Mucinous carcinomas constitute 2.5% of GB carcinomas. They present with an acute cholecystitis-type picture. Most MCs are a mixed-mucinous, not pure colloid, type. They are typically large and advanced tumors at the time of diagnosis and thus exhibit more-aggressive behavior than do ordinary GB carcinomas. Immunophenotypically, they differ from conventional GB adenocarcinomas by MUC2 positivity, from intestinal carcinomas by an often inverse CK7/20 profile, from pancreatic mucinous carcinomas by CDX2 negativity, and from mammary colloid carcinomas by a lack of MUC6. Unlike gastrointestinal MCs, they appear to be microsatellite stable.