Subgrading of G2 Pancreatic Neuroendocrine Tumors as 2A (Ki67 3% to < 10%) Versus 2B (10% to ≤ 20%) Identifies Behaviorally Distinct Subsets in Keeping with the Evolving Management Protocols.

BACKGROUND: Grade 1/2 PanNETs are mostly managed similarly, typically without any adjunct treatment with the belief that their overall metastasis rate is low. In oncology literature, Ki67-index of 10% is increasingly being used as the cutoff in stratifying patients to different protocols, although there are no systematic pathology-based studies supporting this approach. METHODS: Ki67-index was correlated with clinicopathologic parameters in 190 resected PanNETs. A validation cohort (n = 145) was separately analyzed. RESULTS: In initial cohort, maximally selected rank statistics method revealed 12% to be the discriminatory cutoff (close to 10% rule of thumb). G2b cases had liver/distant metastasis rate of almost threefold higher than that of G2a and showed significantly higher frequency of all histopathologic signs of aggressiveness (tumor size, perineural/vascular invasion, infiltrative growth pattern, lymph node metastasis). In validation cohort, these figures were as striking. When all cases were analyzed together, compared with G1, the G2b category had nine times higher liver/distant metastasis rate (6.1 vs. 58.5%; p < 0.001) and three times higher lymph node metastasis rate (20.5 vs. 65.1%; p < 0.001). CONCLUSIONS: G2b PanNETs act very similar to G3, supporting management protocols that regard them as potential therapy candidates. Concerning local management, metastatic behavior in G2b cases indicate they may not be as amenable for conservative approaches, such as watchful waiting or enucleation. This substaging should be considered into diagnostic guidelines, and clinical trials need to be devised to determine the more appropriate management protocols for G2b (10% to ≤ 20%) group, which shows liver/distant metastasis in more than half of the cases, which at minimum warrants closer follow-up.

Investigation of the usefulness of a bile duct biopsy and bile cytology using a hyperspectral camera and machine learning.

To improve the efficiency of pathological diagnoses, the development of automatic pathological diagnostic systems using artificial intelligence (AI) is progressing; however, problems include the low interpretability of AI technology and the need for large amounts of data. We herein report the usefulness of a general-purpose method that combines a hyperspectral camera with machine learning. As a result of analyzing bile duct biopsy and bile cytology specimens, which are especially difficult to determine as benign or malignant, using multiple machine learning models, both were able to identify benign or malignant cells with an accuracy rate of more than 80% (93.3% for bile duct biopsy specimens and 83.2% for bile cytology specimens). This method has the potential to contribute to the diagnosis and treatment of bile duct cancer and is expected to be widely applied and utilized in general pathological diagnoses.

Interobserver agreement of pathologic classification and grading of tumoral intraductal pre-invasive neoplasms of the bile duct.

Current WHO terminology and recent publications have classified tumoral (grossly visible) intraductal pre-invasive neoplasms of bile duct (TIDN) into three categories: intraductal papillary neoplasm of bile duct (IPNB), intraductal papillary oncocytic neoplasm (IOPN), and intraductal tubulopapillary neoplasm (ITPN). A total of 227 cases of TIDN and related lesions ≥3 mm in height were examined by 10 biliary pathologists referring to these 3 categories and two pathologic gradings: two-tiered system (low- and high-grade dysplasia) and modified types 1 and 2 subclassification. Among them, IPNB was the most frequent (183 cases), followed by IOPN (28 cases), while ITPN was rare (2 cases), and interobserver agreement in this classification was "substantial" (κ-value, 0.657). The interobserver agreement of two-tiered grading system of TIDN was "slight" (κ-value, 0.201), while that of modified types 1 and 2 subclassification was "moderate" (κ-value, 0.515), and 42 % were of type 1, and 58 % were of type 2. Type 1 TIDN showed occasional stromal invasion (6.7 %), whereas type 2 TIDN was frequently associated with stromal invasion (49.6 %) (p < 0.01). In conclusion, the classification of TIDN into three categories and modified types 1 and 2 subclassification are a practically applicable classification and grading system for TIDN.

Sweat-gland carcinoma with neuroendocrine differentiation (SCAND): a clinicopathologic study of 13 cases with genetic analysis.

Low-grade neuroendocrine carcinoma of the skin (LGNECS) was proposed in 2017 as a new primary cutaneous neoplasm with neuroendocrine differentiation; however, it is not yet well known due to its rarity. Herein, we perform a detailed clinicopathologic analysis of 13 cases as well as panel DNA sequencing in three cases. The study included 12 males and 1 female with a median age of 71 (43-85) years. All lesions occurred on the ventral trunk. The mean tumor size was 2.2 (0.8-11.0) cm. The histopathology resembled that of well-differentiated neuroendocrine tumors (NETs) in other organs, but intraepidermal pagetoid spreading was seen in 8 (61.5%) cases and stromal mucin deposits in 4 (30.8%). Immunoreactivity for CK7, CK19, EMA, BerEP4, CEA, chromogranin A, synaptophysin, INSM1, GCDFP15, GATA3, ER, and bcl-2 were present in varying degrees in all tested cases. PTEN c.165-1G>A splice site mutation was detected by panel sequencing in one case, and GATA3 P409fs*99 and SETD2 R1708fs*4 in another case. Lymph node metastasis was seen significantly in cases with tumor size >2.0 cm [8/8 (100%) vs. 1/5 (20%)]. All three cases with size >3.0 cm were in unresectable advanced-stage [3/3 (100%) vs. 1/10 (10%)], and two of the three patients succumbed to the disease. The two cases of death revealed mild nuclear atypia (mitosis: 1/10 HPFs) and moderate nuclear atypia (2/10 HPFs). Thus, tumor size would be a better prognostic factor than nuclear atypia, mitotic count, and Ki67 index, unlike in NETs. These clinicopathologic and immunohistochemical features would represent the characteristics as skin adnexal tumors with apocrine/eccrine differentiation rather than NETs; therefore, we rename it as sweat-gland carcinoma with neuroendocrine differentiation (SCAND).

Pancreatic hamartoma: detection of harbouring NAB2::STAT6 fusion gene.

Hamartomas in the pancreas are rare and are often histologically and morphologically similar to solitary fibrous tumours (SFTs). We examined the differences between hamartomas and SFTs at the molecular level. METHODS AND RESULTS: Thirteen patients histopathologically diagnosed with pancreatic hamartoma were included in the study. We also performed STAT6 immunohistochemistry (IHC), which is used in the diagnosis of SFT. Furthermore, for the three cases in which RNA was extracted, reverse transcription polymerase chain reaction to search for NAB2::STAT6 fusions was used. Macroscopically, 13 patients had well-demarcated tumour lesions. Histologically, no islets of Langerhans were observed in the lesions, acinar tissue and ducts were unevenly distributed and elastic fibres were not observed around the ducts by Elastica van Gieson staining. One case contained a lipomatous hamartoma composed mainly of adipose tissue. Seven of the 13 cases demonstrated expression of STAT6 in the nuclei of intervening spindle cells. NAB2::STAT6 fusions were observed in two of the three cases in which RNA was extracted. These two cases also demonstrated STAT6 expression in spindle cells using STAT6 IHC. In one case of lipomatous hamartoma, we did not confirm NAB2::STAT6 fusion or STAT6 expression in STAT6 IHC. CONCLUSION: Of the 13 patients histopathologically diagnosed with hamartoma, two demonstrated NAB2::STAT6 fusions, suggesting the existence of pancreatic hamartomas with molecular-level components identical to those of SFT.

Can the location of the mural nodule indicate benign or malignant in branch duct-type intraductal papillary mucinous neoplasm of the pancreas?

BACKGROUND/OBJECTIVES: Intraductal papillary mucinous neoplasms (IPMNs) are classified into main duct (MD)-type IPMNs, branch duct (BD)-type IPMNs, and mixed type IPMNs. While MD-type IPMN has a high risk of malignancy and should therefore be considered for resection if the patient is fit, BD-type IPMN needs to be carefully judged for surgical indication. The decision to resect BD-type IPMN is often based on international consensus Fukuoka guidelines 2017, but further investigation is required. In this study, we focused on whether the location of the mural nodule (MN) could be an indicator of malignancy. METHODS: We enrolled 17 cases who had been diagnosed BD-type IPMNs which were surgically resected from January 2016 to December 2019. These cases were classified into benign and malignant group. Subsequently, a clinicopathological study was conducted based on the localization of MN (MN-central type or MN-peripheral type). RESULTS: Although MN was found in 57% (4/11) in the benign group, 88% (7/8) was noted in the malignant group, indicating the presence of MN to be more common in the malignant group. Those with MN consisted of 6 cases of MN-central type and 5 cases of MN-peripheral type. All cases of central type were malignant compared to only one case of the peripheral group being confirmed on histology as cancer. CONCLUSION: BD-IPMN with central mural nodule should be considered high risk for malignancy.

Molecular alterations associated with metastases of solid pseudopapillary neoplasms of the pancreas.

Solid pseudopapillary neoplasms (SPN) of the pancreas are rare, low-grade malignant neoplasms that metastasise to the liver or peritoneum in 10-15% of cases. They almost invariably present somatic activating mutations of CTNNB1. No comprehensive molecular characterisation of metastatic disease has been conducted to date. We performed whole-exome sequencing and copy-number variation (CNV) analysis of 10 primary SPN and comparative sequencing of five matched primary/metastatic tumour specimens by high-coverage targeted sequencing of 409 genes. In addition to CTNNB1-activating mutations, we found inactivating mutations of epigenetic regulators (KDM6A, TET1, BAP1) associated with metastatic disease. Most of these alterations were shared between primary and metastatic lesions, suggesting that they occurred before dissemination. Differently from mutations, the majority of CNVs were not shared among lesions from the same patients and affected genes involved in metabolic and pro-proliferative pathways. Immunostaining of 27 SPNs showed that loss or reduction of KDM6A and BAP1 expression was significantly enriched in metastatic SPNs. Consistent with an increased transcriptional response to hypoxia in pancreatic adenocarcinomas bearing KDM6A inactivation, we showed that mutation or reduced KDM6A expression in SPNs is associated with increased expression of the HIF1α-regulated protein GLUT1 at both primary and metastatic sites. Our results suggest that BAP1 and KDM6A function is a barrier to the development of metastasis in a subset of SPNs, which might open novel avenues for the treatment of this disease. © 2018 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

Guidance for diagnosing autoimmune pancreatitis with biopsy tissues.

The biopsy-based diagnosis of autoimmune pancreatitis (AIP) is difficult but is becoming imperative for pathologists due to the increased amount of endoscopic ultrasound-guided biopsy tissue. To cope with this challenge, we propose guidance for the biopsy diagnosis of type 1 AIP. This guidance is for pathologists and comprises three main parts. The first part includes basic issues on tissue acquisition, staining, and final diagnosis, and is intended for gastroenterologists as well. The second part is a practical guide for diagnosing type 1 AIP based on the AIP clinical diagnostic criteria 2018. Inconsistent histological findings, tips for evaluating IgG4 immunostaining and key histological features including the ductal lesion and others are explained. Storiform fibrosis and obliterative phlebitis are diagnostic hallmarks but are sometimes equivocal. Storiform fibrosis is defined as spindle-shaped cells, inflammatory cells and fine collagen fibers forming a flowing arrangement. Obliterative phlebitis is defined as fibrous venous obliteration with inflammatory cells. Examples of each are provided. The third part describes the differentiation of AIP from pancreatic ductal adenocarcinoma (PDAC), focusing on histological features of acinar-ductal metaplasia in AIP, which is an important mimicker of PDAC. This guidance will help standardize pathology reports of pancreatic biopsies for diagnosing type 1 AIP.

[Six cases of anaplastic pancreatic carcinoma diagnosed by endoscopic ultrasound-guided fine needle aspiration].

Anaplastic pancreatic carcinoma is a rare form of pancreatic cancer with an extremely poor prognosis. Its diagnosis is often based on surgical specimens and few reports have described the use of endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) for diagnosis. In this study, we examined six patients (mean age, 70.5 years;sex ratio, 1:1) who were diagnosed with anaplastic pancreatic carcinoma using EUS-FNA. The carcinomas were located in the pancreatic head, body, and tail in one, three, and two patients, respectively. The mean tumor diameter was 49.2mm. Five patients opted for best supportive care due to poor performance status and one underwent chemotherapy (GEM+nab-PTX). The median survival was 40.5 (14-98) days. The characteristic imaging findings of anaplastic pancreatic carcinoma, including central necrosis, marginal contrast enhancement, cystic findings, and internal calcification, were frequently observed in the patients. Anaplastic pancreatic carcinoma can also be diagnosed using biopsy tissue;however, a pathologist's consultation is required to differentiate the disease based on imaging findings for an accurate diagnosis.

A case of rectal neuroendocrine carcinoma in a patient with long-standing ulcerative colitis involving alterations of the p16-Rb pathway.

The patient was a 54-year-old male who had been suffering from extensive ulcerative colitis (UC) for 17 years. Colonoscopy revealed an elevated lesion in the affected rectum, and its biopsy demonstrated neuroendocrine carcinoma (NEC). The surgical specimen obtained on laparoscopic high anterior resection showed extensive active inflammatory and dysplastic lesions and three grossly visible multifocal malignant lesions: a polypoid fungating tumor of NEC (type 1, 20 mm in diameter, pT3) that had been preoperatively noticed, a polypoid fungating tumor of adenocarcinoma (type 1, 22 mm, pT2) and a protruded sessile polypoid tumor (0-Is, 5 mm, pTis) of adenocarcinoma. The NEC was adjacently accompanied by dysplasia-carcinoma sequential lesions and showed a diffuse immunohistochemical overexpression of p53 and p16 proteins and the loss of Rb with no abnormal immunohistochemical staining of microsatellite instability markers and no KRAS mutations. Fifteen months later, the patient showed liver metastasis from the NEC component, followed by bone and spinal metastasis; he died 22 months after the initial diagnosis. A rare case of lethal NEC arising from long-standing extensive UC was reported. The NEC appeared to be UC-related, not incidental, and complicated by progression from dysplasia to carcinoma involving alterations of the p16-Rb pathway.

Magnetic Resonance Imaging of a Urethral Caruncle and the Pathologic Correlation: A Report of 3 Cases.

A urethral caruncle is the most common disease of the urethra in postmenopausal women. A definitive diagnosis can usually be reached based on physical examination. Cross-sectional imaging is performed when malignant urethral tumor is suspected, such as a urethral carcinoma. No articles have discussed the detailed imaging of urethral caruncles. We present 3 patients with symptomatic urethral caruncles who underwent magnetic resonance imaging preoperatively.

Pathologic Evaluation and Reporting of Intraductal Papillary Mucinous Neoplasms of the Pancreas and Other Tumoral Intraepithelial Neoplasms of Pancreatobiliary Tract: Recommendations of Verona Consensus Meeting.

BACKGROUND: There are no established guidelines for pathologic diagnosis/reporting of intraductal papillary mucinous neoplasms (IPMNs). DESIGN: An international multidisciplinary group, brought together by the Verona Pancreas Group in Italy-2013, was tasked to devise recommendations. RESULTS: (1) Crucial to rule out invasive carcinoma with extensive (if not complete) sampling. (2) Invasive component is to be documented in a full synoptic report including its size, type, grade, and stage. (3) The term "minimally invasive" should be avoided; instead, invasion size with stage and substaging of T1 (1a, b, c; ≤ 0.5, > 0.5-≤ 1, > 1 cm) is to be documented. (4) Largest diameter of the invasion, not the distance from the nearest duct, is to be used. (5) A category of "indeterminate/(suspicious) for invasion" is acceptable for rare cases. (6) The term "malignant" IPMN should be avoided. (7) The highest grade of dysplasia in the non-invasive component is to be documented separately. (8) Lesion size is to be correlated with imaging findings in cysts with rupture. (9) The main duct diameter and, if possible, its involvement are to be documented; however, it is not required to provide main versus branch duct classification in the resected tumor. (10) Subtyping as gastric/intestinal/pancreatobiliary/oncocytic/mixed is of value. (11) Frozen section is to be performed highly selectively, with appreciation of its shortcomings. (12) These principles also apply to other similar tumoral intraepithelial neoplasms (mucinous cystic neoplasms, intra-ampullary, and intra-biliary/cholecystic). CONCLUSIONS: These recommendations will ensure proper communication of salient tumor characteristics to the management teams, accurate comparison of data between analyses, and development of more effective management algorithms.

Ampullary carcinoma is often of mixed or hybrid histologic type: an analysis of reproducibility and clinical relevance of classification as pancreatobiliary versus intestinal in 232 cases.

Histologic classification of ampullary carcinomas as intestinal versus pancreatobiliary is rapidly becoming a part of management algorithms, with immunohistochemical classification schemes also being devised using this classification scheme as their basis. However, data on the reproducibility and prognostic relevance of this classification system are limited. In this study, five observers independently evaluated 232 resected ampullary carcinomas with invasive component >3 mm. Overall interobserver agreement was 'fair' (κ 0.39; P<0.001) with complete agreement in 23%. Using agreement by 3/5 observers as 'consensus' 40% of cases were classified as 'mixed' pancreatobiliary and intestinal. When observers were asked to provide a final diagnosis based on the predominant pattern in cases initially classified as mixed, there was 'moderate' agreement (κ 0.44; P<0.0001) with 5/5 agreeing in 35%. Cases classified as pancreatobiliary by consensus (including those with pure-pancreatobiliary or mixed-predominantly pancreatobiliary features) had shorter overall (median 41 months) and 5-year survival (38%) than those classified as pure-intestinal/mixed-predominantly intestinal (80 months and 57%, respectively; P=0.026); however, on multivariate analysis this was not independent of established prognostic parameters. Interestingly, when compared with 476 cases of pancreatic ductal adenocarcinomas, the pancreatobiliary-type ampullary carcinomas had better survival (16 versus 41 months, P<0.001), even when matched by size and node status. In conclusion, presumably because of the various cell types comprising the region, ampullary carcinomas frequently show mixed phenotypes and intratumoral heterogeneity, which should be considered when devising management protocols. Caution is especially warranted when applying this histologic classification to biopsies and tissue microarrays. While ampullary carcinomas with more pancreatobiliary morphology have a worse prognosis than intestinal ones this does not appear to be an independent prognostic factor. However, pancreatobiliary-type ampullary carcinomas have a much better prognosis than their pancreatic counterparts.

Intrapancreatic distal common bile duct carcinoma: Analysis, staging considerations, and comparison with pancreatic ductal and ampullary adenocarcinomas.

Distal common bile duct carcinoma is a poorly characterized entity for reasons such as variable terminology and difficulty in determining site of origin of intrapancreatic lesions. We compared clinicopathologic features of pancreatobiliary-type adenocarcinomas within the pancreas, but arising from the distal common bile duct, with those of pancreatic and ampullary origin. Upon careful review of 1017 pancreatoduodenectomy specimens with primary adenocarcinoma, 52 (5%) qualified as intrapancreatic distal common bile duct carcinoma. Five associated with an intraductal papillary neoplasm were excluded; the remaining 47 were compared to 109 pancreatic ductal adenocarcinomas and 133 ampullary carcinomas. Distal common bile duct carcinoma patients had a younger median age (58 years) than pancreatic ductal adenocarcinoma patients (65 years) and ampullary carcinoma patients (68 years). Distal common bile duct carcinoma was intermediate between pancreatic ductal adenocarcinoma and ampullary carcinoma with regard to tumor size and rates of node metastases and margin positivity. Median survival was better than for pancreatic ductal adenocarcinoma (P=0.0010) but worse than for ampullary carcinoma (P=0.0006). Distal common bile duct carcinoma often formed an even band around the common bile duct and commonly showed intraglandular neutrophil-rich debris and a small tubular pattern. Poor prognostic indicators included node metastasis (P=0.0010), lymphovascular invasion (P=0.0299), and margin positivity (P=0.0069). Categorizing the tumors based on size also had prognostic relevance (P=0.0096), unlike categorization based on anatomic structures invaded. Primary distal common bile duct carcinoma is seen in younger patients than pancreatic ductal adenocarcinoma or ampullary carcinoma. Its prognosis is significantly better than pancreatic ductal adenocarcinoma and worse than ampullary carcinoma, at least partly because of differences in clinical presentation. Use of size-based criteria for staging appears to improve its prognostic relevance. Invasive pancreatobiliary-type distal common bile duct carcinomas are uncommon in the West and have substantial clinicopathologic differences from carcinomas arising from the pancreas and ampulla.

Calculation of the Ki67 index in pancreatic neuroendocrine tumors: a comparative analysis of four counting methodologies.

Ki67 index is now an essential part of classification of pancreatic neuroendocrine tumors. However, its adaptation into daily practice has been fraught with challenges related to counting methodology. In this study, three reviewers used four counting methodologies to calculate Ki67 index in 68 well-differentiated pancreatic neuroendocrine tumors: (1) 'eye-ball' estimation, which has been advocated as reliable and is widely used; (2) automated counting by image analyzer; (3) manual eye-counting (eye under a microscope without a grid); and (4) manual count of camera-captured/printed image. Pearson's correlation (R) was used to measure pair-wise correlation among three reviewers using all four methodologies. Average level of agreement was calculated using mean of R values. The results showed that: (1) 'eye-balling' was least expensive and fastest (average time <1 min) but had poor reliability and reproducibility. (2) Automated count was the most expensive and least practical with major impact on turnaround time (limited by machine and personnel accessibility), and, more importantly, had inaccuracies in overcounting unwanted material. (3) Manual eye count had no additional cost, averaged 6 min, but proved impractical and poorly reproducible. (4) Camera-captured/printed image was most reliable, had highest reproducibility, but took longer than 'eye-balling'. In conclusion, based on its comparatively low cost/benefit ratio and reproducibility, camera-captured/printed image appears to be the most practical for calculating Ki67 index. Although automated counting is generally advertised as the gold standard for index calculation, in this study it was not as accurate or cost-effective as camera-captured/printed image and was highly operator-dependent. 'Eye-balling' produces highly inaccurate and unreliable results, and is not recommended for routine use.

Substaging Nodal Status in Ampullary Carcinomas has Significant Prognostic Value: Proposed Revised Staging Based on an Analysis of 313 Well-Characterized Cases.

BACKGROUND: Current nodal staging (N-staging) of ampullary carcinoma in the TNM staging system distinguishes between node-negative (N0) and node-positive (N1) disease but does not consider the metastatic lymph node (LN) number. METHODS: Overall, 313 patients who underwent pancreatoduodenectomy for ampullary adenocarcinoma were categorized as N0, N1 (1-2 metastatic LNs), or N2 (≥3 metastatic LNs), as proposed by Kang et al. Clinicopathological features and overall survival (OS) of the three groups were compared. RESULTS: The median number of LNs examined was 11, and LN metastasis was present in 142 cases (45 %). When LN-positive cases were re-classified according to the proposed staging system, 82 were N1 (26 %) and 60 were N2 (19 %). There was a significant correlation between proposed N-stage and lymphovascular invasion, perineural invasion, increased tumor size (each p < 0.001), and surgical margin positivity (p = 0.001). The median OS in LN-negative cases was significantly longer than that in LN-positive cases (107.5 vs. 32 months; p < 0.001). Patients with N1 and N2 disease had median survivals of 40 and 24.5 months, respectively (p < 0.0001). In addition, 1-, 3-, and 5-year survivals were 88, 76, 62 %, respectively, for N0; 90, 55, 31.5 %, respectively, for N1; and 68, 34, 30 %, respectively for N2 (p < 0.001). Even with multivariate modeling, the association between higher proposed N stage and shorter survival persisted (hazard ratio 1.6 for N1 and 1.9 for N2; p = 0.018). CONCLUSIONS: Classification of nodal status in ampullary carcinomas based on the number of metastatic LNs has a significant prognostic value. A revised N-staging classification system should be incorporated into the TNM staging of ampullary cancers.

A case of Degos disease: demonstration of C5b-9-mediated vascular injury.

A 68-year-old Japanese male presented with atrophic erythematous white lesions with peripheral dark reddish rims on his back. Multiple ulcers were detected from his stomach to his large intestine using endoscopy. Although the patient was given high doses of a steroid, aspirin, dipyridamole, and intravenous immunoglobulin therapy, he died of gastrointestinal hemorrhage, perforation and septic shock. An autopsy examination revealed pauci-inflammatory thrombotic microangiopathy with endothelial cell injury, fibrous occlusive arteriopathy, and vascular C5b-9 deposition in the wall of the gastrointestinal tract from the esophagus to the large intestine as well as in the dermis of the skin.