Three Distinct Stroma Types in Human Pancreatic Cancer Identified by Image Analysis of Fibroblast Subpopulations and Collagen

PURPOSE

Cancer-associated fibroblasts have emerged to be highly heterogenous and can play multifaceted roles in dictating pancreatic ductal adenocarcinoma (PDAC) progression, immunosuppression, and therapeutic response, highlighting the need for a deeper understanding of stromal heterogeneity between patients and even within a single tumor. We hypothesized that image analysis of fibroblast subpopulations and collagen in PDAC tissues might guide stroma-based patient stratification to predict clinical outcomes and tumor characteristics.

EXPERIMENTAL DESIGN

A novel multiplex IHC-based image analysis system was established to digitally differentiate fibroblast subpopulations. Using whole-tissue slides from 215 treatment-naïve PDACs, we performed concurrent quantification of principal fibroblast subpopulations and collagen and defined three stroma types: collagen-rich stroma, fibroblast activation protein α (FAP)-dominant fibroblast-rich stroma, and α smooth muscle actin (ACTA2)-dominant fibroblast-rich stroma. These stroma types were assessed for the associations with cancer-specific survival by multivariable Cox regression analyses and with clinicopathologic factors, including CD8⁺ cell density.

RESULTS

FAP-dominant fibroblasts and ACTA2-dominant fibroblasts represented the principal distinct fibroblast subpopulations in tumor stroma. Stroma types were associated with patient survival, SMAD4 status, and transcriptome signatures. Compared with FAP-dominant fibroblast-rich stroma, collagen-rich stroma correlated with prolonged survival [HR, 0.57; 95% confidence interval (CI), 0.33-0.99], while ACTA2-dominant fibroblast-rich stroma exhibited poorer prognosis (HR, 1.65; 95% CI, 1.06-2.58). FAP-dominant fibroblast-rich stroma was additionally characterized by restricted CD8⁺ cell infiltrates and intense neutrophil infiltration.

CONCLUSIONS

This study identified three distinct stroma types differentially associated with survival, immunity, and molecular features, thereby underscoring the importance of stromal heterogeneity in subtyping pancreatic cancers and supporting the development of antistromal therapies.

Clinicopathological features of hepatocellular carcinoma with fatty change: Tumors with macrovesicular steatosis have better prognosis and aberrant expression patterns of perilipin and adipophilin

The clinicopathological characteristics of steatosis in hepatocellular carcinoma (HCC) remain unclear. Here, we elucidate the features of macrovesicular steatosis (MaS) and microvesicular steatosis (MiS) in HCC and their relationships with background liver steatosis. A total of 165 HCC lesions were classified as MaS-HCC, MiS-HCC, or conventional HCC (cHCC) according to the cutoff value of 30% MaS or MiS in tumor cells. We analyzed the clinicopathological differences among these groups. MaS-HCC had less portal vein invasion, a higher proportion of HCC with intratumoral fibrosis, and a lower cumulative risk of recurrence than MiS-HCC or cHCC. Moreover, both MaS-HCC and MiS-HCC had lower incidences of hepatitis virus infection and higher levels of HbA1c than cHCC. Background liver steatosis was also higher in MaS-HCC than in cHCC. Immunohistochemical expression of perilipin (Plin1) and adipophilin (ADRP), major proteins expressed on lipid droplet membranes, revealed that almost all lipid droplets in HCC were Plin1 negative, whereas those in background liver were positive. In contrast, ADRP was expressed on lipid droplets in both HCC and background liver. We concluded that MaS-HCC and MiS-HCC were associated with metabolic abnormalities but exhibited different biologic behaviors. Furthermore, lipid droplets in HCC were pathophysiologically different from those in background liver.

Late-onset visceral varicella-zoster virus infection presented as acute liver failure after allogeneic hematopoietic stem cell transplantation

Although much less common than localized zoster, initial presentation of varicella-zoster virus (VZV) as visceral infection can occur especially after allogeneic hematopoietic stem cell transplantation (HSCT). We herein report a case of post-transplant visceral VZV infection presenting as fatal acute liver failure. It developed 4 years after allogeneic HSCT when a long-term prophylactic anti-VZV agent administration was discontinued. VZV should be listed as a causative pathogen of acute liver failure even years after allogeneic HSCT. Indication for, and duration of anti-VZV prophylaxis should be further investigated.

Concurrent presentation of an intraductal tubulopapillary neoplasm and intraductal papillary mucinous neoplasm in the branch duct of the pancreas, with a superior mesenteric artery aneurysm: a case report

Background

Since the concept of intraductal tubulopapillary neoplasm (ITPN) was introduced in the current World Health Organization classification of tumors, the number of reports of ITPN occurrence has increased gradually. However, ITPN is usually located in the main pancreatic duct, with few reports of a branch duct ITPN. As a result, imaging protocols for the diagnosis of a branch duct ITPN have not been established.

Case presentation

We report a case of a concurrent presentation of a branch duct ITPN and intraductal papillary mucinous neoplasm (IPMN) in the head of the pancreas, with a superior mesenteric artery (SMA) aneurysm. Initially, the cystic masses in the pancreatic head were diagnosed as branch duct IPMNs, with treatment consisting of a pylorus-preserving pancreaticoduodenectomy, in combination with an aneurysmectomy performed for treatment of the SMA aneurysm. Pathological examination confirmed these cysts were a combination of branch-type ITPN and IPMN. The patient recovered from the treatment without complication, with no evidence of recurrence over a period of 34 months post-surgery.

Conclusion

This case report of a synchronous presentation of an ITPN and IPMN indicates the difficulty in differentiating these two types of neoplasms in the branch duct of the pancreatic head.

KRAS mutations in cell-free DNA from preoperative and postoperative sera as a pancreatic cancer marker: a retrospective study

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) has very poor prognosis despite existing multimodal therapies. This study aimed to investigate whether KRAS mutations at codons 12/13 in cell-free DNA (cfDNA) from preoperative and postoperative sera from patients with PDAC can serve as a predictive biomarker for treatment response and outcomes after surgery.

METHODS

Preoperative and postoperative serum samples obtained from 45 patients with PDAC whom underwent curative pancreatectomy at our institution between January 2013 and July 2016 were retrospectively analysed. Peptide nucleic acid-directed PCR clamping was used to identify KRAS mutations in cfDNA.

RESULTS

Among the 45 patients enrolled, 11 (24.4%) and 20 (44.4%) had KRAS mutations in cfDNA from preoperative and postoperative sera, respectively. Multivariate analysis revealed that KRAS mutations in postoperative serum (hazard ratio (HR)=2.919; 95% confidence interval (CI)=1.109-5.621; P=0.027) are an independent prognostic factor for disease-free survival. Furthermore, the shift from wild-type KRAS in preoperative to mutant KRAS in postoperative cfDNA (HR=9.419; 95% Cl=2.015-44.036; P=0.004) was an independent prognostic factor for overall survival.

CONCLUSIONS

Changes in KRAS mutation status between preoperative and postoperative cfDNA may be a useful predictive biomarker for survival and treatment response.

Two cases of pancreatic ductal adenocarcinoma with intrapancreatic metastasis

There are no standardized diagnostic criteria for intrapancreatic metastasis of pancreatic ductal adenocarcinoma (PDAC). Here, we report two cases of patients with PDAC who were pathologically diagnosed as harboring intrapancreatic metastasis. In both cases, the main lesions were located in the pancreatic body, and no other lesion was detected preoperatively. The patients were diagnosed with pancreatic body cancers and distal pancreatectomy was performed. Pathological findings revealed microscopic cancer nests, which had connections to neither the main lesion nor the premalignant lesion in the pancreatic tail parenchyma. In both cases, the histological type of the daughter lesion was quite similar to that of the main lesion. Hence, we diagnosed the daughter lesions as metastatic foci in the pancreas. Although intrapancreatic metastasis of PDAC has been regarded as a poor prognostic factor, few reports of intrapancreatic metastasis are available. This article reports two such cases and provides a review of the literature.

Anisakiasis mimics cancer recurrence: two cases of extragastrointestinal anisakiasis suspected to be recurrence of gynecological cancer on PET-CT and molecular biological investigation

BACKGROUND

We report two cases of anisakiasis lesions that were initially suspected to be recurrence of gynecological cancer by positron emission tomography-computed tomography (PET-CT). Both cases were extragastrointestinal anisakiasis that is very rare.

CASE PRESENTATION

The first case was a patient with endometrial cancer. At 19 months after surgery, a new low density area of 2 cm in diameter in liver segment 4 was found on follow-up CT. In PET-CT, the lesion had abnormal (18)fluoro-deoxyglucose (FDG) uptake with elevation in the delayed phase, with no other site showing FDG uptake. Partial liver resection was performed. A pathological examination revealed no evidence of malignancy, but showed necrotic granuloma with severe eosinophil infiltration and an irregular material with a lumen structure in the center. Parasitosis was suspected and consultation with the National Institute of Infectious Diseases (NIID) showed the larvae to be Anisakis simplex sensu stricto by genetic examination. The second case was a patient with low-grade endometrial stromal sarcoma (LG-ESS). At 8 months after surgery, swelling of the mediastinal lymph nodes was detected on CT and peripheral T-cell lymphoma was diagnosed by biopsy. A new peritoneal lesion with abnormal FDG uptake was detected on pre-treatment PET-CT and this lesion was increased in size on post-treatment PET-CT. Tumorectomy was performed based on suspected dissemination of LG-ESS recurrence. The findings in a pathological examination were similar to the first case and we again consulted the NIID. The larvae was identified as Anisakis pegreffi, which is a rare pathogen in humans. Having experienced these rare cases, we investigated the mechanisms of FDG uptake in parasitosis lesions by immunohistochemical staining using antibodies to glucose transporter type 1 (GLUT-1) and hexokinase type 2 (HK-2). While infiltrated eosinophils were negative, macrophages demonstrated positive for both antibodies. Therefore, mechanisms behind FDG uptake may involve macrophages, which is common among various granulomas. This is the first report to investigate parasitosis in such a way.

CONCLUSION

These cases suggest that anisakiasis is a potential differential diagnosis for a lesion with FDG uptake in PET-CT, and that it is difficult to distinguish this disease from a recurrent tumor using PET-CT alone.

Early hepatocellular carcinoma with high-grade atypia in small vaguely nodular lesions

Multistep hepatocarcinogenesis progresses from dysplastic nodules to early hepatocellular carcinoma (eHCC) and to advanced HCC. The aim of the present study was to investigate the detailed histopathological features of eHCC. We investigated 66 small vaguely nodular lesions resected from 40 patients. The degree of cellular and structural atypia and stromal invasion were assessed. The immunohistochemical expression of HCC‐related markers adenylate cyclase‐associated protein 2 (CAP2), heat shock protein 70 (HSP70), Bmi‐1, CD34 and h‐caldesmon were evaluated. Of the 66 nodules, 10 were diagnosed as low‐grade dysplastic nodules (LGDN), 10 as high‐grade dysplastic nodules (HGDN) and 46 as eHCC. Among the 46 eHCC, 18 nodules (39.1%) showed marked stromal invasion and/or the presence of the scirrhous component and were subclassified as high‐grade eHCC (HGeHCC). The remaining 28 eHCC, which lacked these features, were subclassified as low‐grade eHCC (LGeHCC) and were examined further. HGeHCC showed high levels of cellular and structural atypia and large tumor size. The immunohistochemical expression of CAP2 and the area of sinusoidal vascularization showed increases from LGDN to HGeHCC. The density of arterial tumor vessels was high in HGeHCC compared with other nodule types. Cluster analysis of these parameters subclassified 65 nodules into HGeHCC‐dominant, LGeHCC and HGDN‐dominant, and LGDN‐dominant groups. These results indicate the increased malignant potential of HGeHCC and suggest that it is already a transitional stage to advanced HCC. We consider that our grading classification system may be valuable for considering treatment strategies for eHCC around 2 cm in diameter.

Two Cases of Pathological Complete Response to Neoadjuvant Chemoradiation Therapy in Pancreatic Cancer

Neoadjuvant chemoradiation therapy (NACRT) is increasingly used in patients with a potentially or borderline resectable pancreatic ductal adenocarcinoma (PDA) and it has been shown to improve survival and reduce locoregional metastatic disease. It is rare for patients with PDA to have a pathological complete response (pCR) to NACRT, but such patients reportedly have a good prognosis. We report the clinicopathological findings of two cases of pCR to NACRT in PDA. Both patients underwent pancreatectomy after NACRT (5-fluorouracil, mitomycin C, cisplatin, and radiation). Neither had residual invasive carcinoma and both showed extensive fibrotic regions with several ducts regarded as having pancreatic intraepithelial neoplasia 3/carcinoma in situ in their post-therapy specimens. It is noteworthy that both patients had a history of a second primary cancer. They both had comparatively good outcomes: one lived for 9 years after the initial pancreatectomy and the other is still alive without recurrence after 2 years.

Cystic tumor of the liver without ovarian-like stroma or bile duct communication: two case reports and a review of the literature

We report two cases of cystic neoplasm of the liver with mucinous epithelium in which both ovarian-like stroma and bile duct communication were absent. The first case was a 41-year-old woman. She underwent right trisegmentectomy due to a multilocular cystic lesion, 15 cm in diameter, with papillary nodular components in the medial segment and right lobe. Histologically, arborizing papillae were seen in the papillary lesion. The constituent neoplastic cells had sufficient cytoarchitectural atypia to be classified as high-grade dysplasia. The second case was a 60-year-old woman. She underwent left lobectomy due to a unilocular cystic lesion, 17 cm in diameter, in the left lobe. Histologically, the cyst wall was lined by low columnar epithelia with slight cellular atypia. In both cases, neither ovarian-like stroma nor bile duct communications were found throughout the resected specimen. According to the most recent World Health Organization (WHO) classification in 2010, cystic tumors of the liver with mucinous epithelium are classified as mucinous cystic neoplasms when ovarian-like stromata are found, and as intraductal papillary neoplasm of bile duct when bile duct communication exists. Therefore, we diagnosed the cystic tumors as ‘biliary cystadenoma’ according to the past WHO classification scheme from 2000. We believe that the combined absence of both ovarian-like stroma and bile duct communication is possible in mucinous cystic tumors of the liver. Herein, we have described the clinicopathologic features of the two cases and reviewed past cases in the literature.