Cytological Ki-67 in pancreatic endocrine tumors: a new "must"?

Endoscopic Ultrasound-Guided Fine-Needle Aspiration of Pancreatic Neuroendocrine Tumors with Rapid On-Site Evaluation: Single-Center Experience

INTRODUCTION

Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) is a highly sensitive and accurate method for identifying pancreatic neuroendocrine tumors (PanNETs). However, research on grading and assessing the Ki67 proliferation index in FNA samples is limited.

METHODS

This study analyzed 335 EUS-FNA cases performed between 2016 and 2022, of which 12 cases of PanNET were further evaluated. The morphology, Ki-67 index, and grading (G) of cell blocks (CBs) obtained from the PanNET aspirations were compared to those of the resected material.

RESULTS

Out of 12 PanNET's with rapid on-site evaluation (ROSE), in FNA samples and CB, 7 (58.3%) cases were G1, while 5 (41.7%) cases were G2. On the other hand, on resection of these cases, 6 (50%) were diagnosed as G1, 5 (41.7%) cases were G2, and 1 case (8.3%) was G3. The average Ki-67 index in CB was 2.92 (min: 1 - max: 10), while in resections it was 4.67 (min: 1 - max: 22). Only 2 (16.6%) showed a discordance between grade and Ki-67, resulting in an overall concordance of over 80%. On average, 1.83 needle passes were made (range: 1-3), while the average number of slides and CBs were 9.33 (range: 1-24) and 2.17 (range: 1-6), respectively. There were no significant differences in the number of passes, slides, or CBs between the consistent and discordant groups.

CONCLUSION

Optimal counting techniques and sensitivity for Ki67 are crucial in grading PanNETs in both aspiration and resection materials. The grade and Ki-67 index demonstrated high concordance when comparing CB and resection. However, in low-volume centers, ROSE support can be beneficial in obtaining sufficient slides and CB for an adequate diagnosis.

MRI radiomics for early prediction of response to vaccine therapy in a transgenic mouse model of pancreatic ductal adenocarcinoma

BACKGROUND

There is a lack of well-established clinical tools for predicting dendritic cell (DC) vaccination response of pancreatic ductal adenocarcinoma (PDAC). DC vaccine treatment efficiency was demonstrated using histological analysis in pre-clinical studies; however, its usage was limited due to invasiveness. In this study, we aimed to investigate the potential of MRI texture features for detection of early immunotherapeutic response as well as overall survival (OS) of PDAC subjects following dendritic cell (DC) vaccine treatment in LSL-KrasG12D;LSL-Trp53R172H;Pdx-1-Cre (KPC) transgenic mouse model of pancreatic ductal adenocarcinoma (PDAC).

MATERIALS AND METHODS

KPC mice were treated with DC vaccines, and tumor growth was dynamically monitored. A total of a hundred and fifty-two image features of T2-weighted MRI images were analyzed using a kernel-based support vector machine model to detect treatment effects following the first and third weeks of the treatment. Moreover, univariate analysis was performed to describe the association between MRI texture and survival of KPC mice as well as histological tumor biomarkers.

RESULTS

OS for mice in the treatment group was 54.8 ± 22.54 days while the control group had 35.39 ± 17.17 days. A subset of three MRI features distinguished treatment effects starting from the first week with increasing accuracy throughout the treatment (75% to 94%). Besides, we observed that short-run emphasis of approximate wavelet coefficients had a positive correlation with the survival of the KPC mice (r = 0.78, p < 0.001). Additionally, tissue-specific MRI texture features showed positive association with fibrosis percentage (r = 0.84, p < 0.002), CK19 positive percentage (r = - 0.97, p < 0.001), and Ki67 positive cells (r = 0.81, p < 0.02) as histological disease biomarkers.

CONCLUSION

Our results demonstrate that MRI texture features can be used as imaging biomarkers for early detection of therapeutic response following DC vaccination in the KPC mouse model of PDAC. Besides, MRI texture can be utilized to characterize tumor microenvironment reflected with histology analysis.

Differential diagnosis between pancreatic neuroendocrine and solid pseudopapillary neoplasms on endoscopic ultrasound-guided fine-needle aspiration. An immunohistochemical study

OBJECTIVES

To evaluate the role of applying a limited panel of immunohistochemical stains on the cellblock preparation from samples obtained by endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) in the aim of differentiating solid pseudopapillary neoplasms (SPNs) from neuroendocrine tumors (NETs). 

METHODS

We retrospectively retrieved all the EUS-FNAs of the pancreas that have a diagnosis of NET or SPN that were performed at 2 tertiary care hospitals in Riyadh, Kingdom of Saudi Arabia from May 2004 to December 2014. Diff-Quik, Papanicolaou, and Immunohistochemistry stains on cellblock preparations were performed.  

RESULTS

Twenty cases were available (16 pancreatic neuroendocrine tumors (pNETs) and 4 SPNs). The pNETs were immunoreactive for synaptophysin, chromogranin A and CD56 while E-cadherin was diffusely to focally cytoplasmic positive. β-catenin was negative or showed focal cytoplasmic immunoreactivity. In comparison, SPNs were positive for vimentin, CD10, CD-56, focally positive for progesterone receptors and synaptophysin, and revealed nuclear immunostaining for β-catenin. They were negative for chromogranin A and E-cadherin. 

CONCLUSION

Based on EUS-FNA samples, nuclear immunoreactivity for β-catenin with loss of membranous immunostaining for E-Cadherin can potentially facilitate differentiating SPNs from pNETs.

Concurrent insulinoma and impaired glucose tolerance suspected as owing to obesity

An obese 68-year-old woman was admitted for examination of fasting hypoglycaemia. A prolonged 18 h fast reduced her plasma glucose without suppressing insulin secretion, while plasma β-hydroxybutyrate levels were suppressed. Despite the prolonged fast, the glucose response to glucagon was increased by 25 mg/dL (1.39 mM) glucose, which is compatible with insulinoma. A 75 g oral glucose tolerance test (75 g OGTT) showed impaired glucose tolerance. An abdominal CT scan revealed a mass lesion in the uncinate process of the pancreas, a finding consistent with the results of angiography and selective artery calcium injection test. The patient then underwent a pancreaticoduodenectomy; the pancreatic mass was histologically diagnosed as benign insulinoma. After surgery, a prolonged 24 h fast caused no hypoglycaemia and the glucose tolerance capacity in 75 g OGTT improved. Eight months after surgery, the patient's body weight had reduced by 10 kg. This is therefore a case of concurrent insulinoma and impaired glucose tolerance.