High-grade precursor lesions can be used as surrogate markers to identify the epicenter of periampullary carcinomas

Comparison of Ampullary and Pancreatic Adenocarcinomas: Smaller Invasion, Common Adenomatous Components, Resectability, and Histology are Factors for Improved Survival for Patients with Ampullary Adenocarcinoma

BACKGROUND

The information on the clinicopathologic/outcome differences between ampullary adenocarcinoma (AC) and pancreatic adenocarcinoma (PC) has been conflicting to the extent that it still is questioned whether ACs need to be recognized separately from PCs.

METHODS

The characteristics of 413 ACs were compared with those of 547 PCs.

RESULTS

The ACs had a better prognosis than the PCs (5-year survival, 57 % vs 23 %; p < 0.001). Even the pancreatobiliary (PB)-type ACs had a better prognosis (5-year survival, 46 % vs 23 %; p < 0.001). Several differences also were identified as contributing factors: (1) the preinvasive adenomatous component often constituted a significant proportion of the mass in ACs (>50 % of the tumor in 16 % vs 1.5 %; p < 0.001); (2) the mean size of the carcinoma was smaller in ACs (2.5 vs 3.2 cm; p < 0.001): when matched for invasion size, the survival advantage of AC was minimized, and when matched for invasion size larger than 2 cm, the survival advantage of AC lost its statistical significance; (3) lymph node (LN) metastases were less common in ACs (49 % vs 71 %; p < 0.001); (4) the definitive R1 rate was lower in ACs (4 % vs 23.5 %; p < 0.001); and (5) non-PB and non-tubular adenocarcinoma types were more common in ACs (17 % vs 3 %; p < 0.001).

CONCLUSIONS

Comparatively, ACs have better clinical survival than PCs. Potential contributing factors are the relative abundance of the preinvasive component, smaller invasion, lower LN metastasis rate, higher resectability, and common occurrence of less aggressive histologic phenotypes (intestinal, medullary, mucinous). However, this survival advantage is sustained even in PB-type ACs, highlighting the importance of accurately determining the site of origin.

Pancreatic Intraepithelial Neoplasia (PanIN) as a Morphologic Marker of Pancreatobiliary Type of Ampullary Carcinoma

The classification of ampullary adenocarcinoma into intestinal and pancreatobiliary sub-types has been found to be important in predicting prognosis and determining therapeutic strategy. Due to considerable inter-observer variability in sub-typing based solely on morphology, higher frequency of poorly differentiated cancers and low incidence of the disease, the histomorphologic classification of ampullary adenocarcinoma remains one of the grey zones in surgical pathology. Pan-IN is a well recognized precursor to pancreatic adenocarcinoma. Three studies have shown concurrent Pan-IN in patients with ampullary carcinoma, but their association with the two sub-types has not yet been reported. Fourteen cases of surgical resection for ampullary adenocarcinoma were retrieved from the archives. The cases were classified into two groups based on the presence or absence of concomitant Pan-IN. All the cases were stained for CK7, CK 20, Villin and CDX 2 and were classified as intestinal or pancreatobiliary types based on the staining pattern. All the 10 cases with Pan-IN stained negative for CDX2 and were classified as pancreatobiliary type (p = 0.01). Of the cases without Pan-IN, 3 were classified as intestinal sub-type based on morphology and CDX2 positivity and 1 was classified as pancreatobiliary type. Concomitant Pan-IN was present in 91% of pancreatobiliary type of ampullary adenocarcinoma. The grade of Pan-IN did not influence the grade or stage of the adenocarcinoma (p > 0.05). The co-occurrence of Pan-IN in a high percentage of the pancreatobiliary sub-type and its complete absence in the intestinal sub-type may serve as a strong differentiator between the two sub-types.

Clinicopathologic and Prognostic Significance of Gallbladder and Cystic Duct Invasion in Distal Bile Duct Carcinoma

Context.—

The roles of the gallbladder and cystic duct (CD) invasions in distal bile duct carcinoma (DBDC) have not been well elucidated.

Objective.—

To define the characteristics and prognostic significance of gallbladder or CD invasions in patients with DBDC.

Design.—

Organ invasion patterns with clinicopathologic features were assessed in 258 resected DBDCs.

Results.—

CD invasions (N = 31) were associated with frequent concomitant pancreatic and/or duodenal invasions (23 of 31, 74%) and showed stromal infiltration (16 of 31, 52%) and intraductal cancerization (15 of 31, 48%) patterns. In only 2 cases, invasions with intraductal cancerization were observed in the gallbladder neck. Conversely, all pancreatic (N = 175) and duodenal (83) invasions developed through stromal infiltration. CD invasions were associated with larger tumor size (P = .001), bile duct margin positivity (P = .001), perineural invasions (P = .04), and higher N categories (P = .007). Patients with pancreatic or duodenal invasions had significantly lower survival rates than those without pancreatic (median, 31.0 versus 93.9 months) or duodenal (27.5 versus 56.8 months, P &lt; .001, both) invasions. However, those with gallbladder or CD invasions did not have different survival times (P = .13). Patients with concomitant gallbladder/CD and pancreatic/duodenal invasions demonstrated significantly lower survival rates than those without organ invasions (P &lt; .001).

Conclusions.—

Gallbladder invasions were rare in DBDCs as neck invasions with intraductal cancerization. CD invasions occurred by stromal infiltrations and intraductal cancerization, whereas all pancreatic and duodenal invasions had stromal infiltration patterns. Gallbladder and/or CD invasions did not affect survival rates of patients with DBDC, while pancreatic and duodenal invasions affected survival rates. Therefore, these differences in survival rates may originate from the different invasive patterns of DBDCs.