The response of pancreatic acinar cell carcinoma to platinum and olaparib therapy in a germline BRCA2 variant carrier: case report and literature review.

A 73-year-old Japanese man with a history of distal biliary cancer treated by pancreatoduodenectomy developed pancreatic acinar cell carcinoma (PACC) treated by remnant pancreatectomy and adjuvant chemotherapy. Thirteen months after surgery, multiple liver metastases developed and FOLFOX chemotherapy was initiated. Based on the PACC diagnosis and a positive family history for breast and ovarian cancer genetic testing was performed which revealed a pathogenic germline BRCA2 variant (c.8629G > T, p.Glu2877Ter). Olaparib therapy was initiated and the metastases responded well (partial response). PACC is a BRCA2-associated cancer which may respond well to PARP inhibitors.

A Japanese Family Meeting the Clinical Diagnostic Criteria for MEN1 with a MEN1 Variant of Uncertain Significance.

Multiple gastroenteric, pancreatic, and pituitary neuroendocrine neoplasms (NENs) were diagnosed in a 74-year-old man with a history of primary hyperparathyroidism (PHPT). Germline testing demonstrated a variant of MEN1 (c.1694T>A, p.L565Q), whose pathogenicity was classified as a variant of uncertain significance (VUS) according to the ACMG/AMP guidelines. The same germline variant was detected in the patient's son and daughter, who also showed PHPT or hypercalcemia and met the clinical diagnostic criteria for multiple endocrine neoplasia type 1 (MEN1). During surveillance of the son, multiple pancreatic tumors suggestive of NENs were detected. The pathogenicity of the current MEN1 variant was re-evaluated as likely pathogenic, based on additional family data.

Discordance of microsatellite instability and mismatch repair immunochemistry occurs depending on the cancer type.

Microsatellite instability (MSI) and deficiency of mismatch repair (dMMR) are key markers for predicting the response of immune checkpoint inhibitors (ICIs) and screening for Lynch syndrome (LS). This study examined the incidences of and factors associated with the concordance of MSI and MMR in human cancers. A total of 518 formalin-fixed cancer tissues were analyzed for MSI and MMR immunohistochemistry (IHC). MSI was analyzed by a PCR-based method using Promega markers. Concordance with MMR expression and factors associated with concordance were analyzed. In 2 colorectal cancer samples, MMR IHC failed due to inadequate staining conditions. In the remaining 516 cancers, a high level of MSI (MSI-H) was identified in 113 cases, and dMMR was identified in 112. The concordance of MSI and MMR IHC was 98.3%. Only 9 cases (4 pancreatobiliary, 3 colorectal, and 2 endometrial cancers) were discordant. Of the 113 MSI-H cases, 4 (3.5%) were proficient MMR (pMMR); of the 403 microsatellite stability (MSS) cases, 5 (1.2%) were dMMR. The independent factors associated with MSI-H/dMMR included meeting Amsterdam II criteria, assay purpose, and sampling method. Multivariate analysis revealed that cancer type (gastrointestinal cancers or others) was associated with concordance of MSI and MMR IHC. Three LS cases with pancreatic or endometrial cancer demonstrated MSS and dMMR, and one biliary cancer showed MSI-H and pMMR. Discordance between MSI and MMR IHC occasionally occurs in pancreaticobiliary and endometrial cancers. When suspected, both MSI and MMR IHC should be done to judge the ICI indication and screen for LS.

Microsatellite instability is biased in Amsterdam II-defined Lynch-related cancer cases with family history but is rare in other cancers: a summary of 1000 analyses.

BACKGROUND: Microsatellite instability (MSI) is a key marker for predicting the response of immune checkpoint inhibitors (ICIs) and for screening Lynch syndrome (LS). AIM: This study aimed to see the characteristics of cancers with high level of MSI (MSI-H) in genetic medicine and precision medicine. METHODS: This study analyzed the incidence of MSI-H in 1000 cancers and compared according to several clinical and demographic factors. RESULTS: The incidence of MSI-H was highest in endometrial cancers (26.7%, 20/75), followed by small intestine (20%, 3/15) and colorectal cancers (CRCs)(13.7%, 64/466); the sum of these three cancers (15.6%) was significantly higher than that of other types (2.5%)(P < 0.0001). MSI-H was associated with LS-related cancers (P < 0.0001), younger age (P = 0.009), and family history, but not with smoking, drinking, or serum hepatitis virus markers. In CRC cases, MSI-H was significantly associated with a family history of LS-related cancer (P < 0.0001), Amsterdam II criteria [odds ratio (OR): 5.96], right side CRCs (OR: 4.89), and multiplicity (OR: 3.31). However, MSI-H was very rare in pancreatic (0.6%, 1/162) and biliary cancers (1.6%, 1/64) and was null in 25 familial pancreatic cancers. MSI-H was more recognized in cancers analyzed for genetic counseling (33.3%) than in those for ICI companion diagnostics (3.1%)(P < 0.0001). Even in CRCs, MSI-H was limited to 3.3% when analyzed for drug use. CONCLUSIONS: MSI-H was predominantly recognized in LS-related cancer cases with specific family histories and younger age. MSI-H was limited to a small proportion in precision medicine especially for non-LS-related cancer cases.

Efficacy of endoscopic samplings during initial biliary drainage for cases of pancreatic head cancer: United diagnostic yields of multiple pathological samplings.

BACKGROUND/OBJECTIVES: The diagnostic ability of endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) has been fully studied; however, the efficacy of other endoscopic samplings (OESs) is less clear. The aim of this study was to examine the diagnostic efficacies of OESs for pancreatic head cancer (PHC). METHODS: The diagnostic efficacies of endoscopic samplings were retrospectively analyzed in 448 PHC cases and 63 cases of mass-forming pancreatitis (MFP) during initial transpapillary biliary drainage. The OESs included duodenal biopsy (118 PHCs and 50 MFPs), biliary biopsy (218 and 51) with cytology (368 and 53), and pancreatic duct biopsy (23 and 13) with cytology (56 and 43). EUS-FNA was conducted in a different session (149 and 62). Factors associated with OES sensitivity were analyzed. The sensitivity of biliary biopsy was compared between 1.95 mm and 1.8 mm forceps. RESULTS: Cancer cells were confirmed in 87.9% of the EUS-FNA samplings and in 64.1% (268/418) obtained by combined OESs (average 1.7 OES types per case): 68.6% by duodenal biopsy, 59.6% by biliary biopsy, 32.6% by biliary cytology, 73.9% by pancreatic duct biopsy, and 33.9% by pancreatic duct cytology. No MFP cases revealed cancer by any sampling. OESs did not increase adverse events. Duodenal stenosis, serum bilirubin, tumor size, and pancreatic juice amounts were associated with OES sensitivity. Biliary biopsy had the same sensitivity with different forceps. CONCLUSION: EUS-FNA was the most diagnostic protocol; however, OESs can be safely applied during the initial biliary drainage to reduce the demand for EUS-FNA while providing good diagnostic yields.

Comparison of five-phase computed tomography images of type 1 autoimmune pancreatitis and pancreatic cancer: Emphasis on cases with atypical images.

BACKGROUND/OBJECTIVES: International consensus diagnostic criteria (ICDC) include characteristic images of autoimmune pancreatitis (AIP); however, reports on atypical cases are increasing. The aims of this study were to compare CT findings between AIP and pancreatic cancer (PC), and to analyze type 1 AIPs showing atypical images. METHODS: Five-phase CT images were compared between 80 type 1-AIP lesions and 80 size- and location-matched PCs in the case-control study. Atypical AIPs were diagnosed based on the four ICDC items. RESULTS: ICDC items were recognized in most AIP lesions; pancreatic enlargement (87.7%), narrowing of the main pancreatic duct (98.8%), delayed enhancement (100%), and no marked upstream-duct dilation (97.5%). CT values of AIPs increased rapidly until the pancreatic phase and decreased afterward, while those of PCs gradually increased until the delayed phase (P < 0.0001). Atypical images were recognized in 14.8% of AIPs, commonly without pancreatic enlargement (18.5 mm) and sometimes mimicking intraductal neoplasms. The CT values and their ratios were different between atypical AIPs and size-matched PCs most significantly in the pancreatic phase, but similar in the delayed phase. CONCLUSIONS: Ordinary type 1 AIPs can be diagnosed with the ICDC, but atypical AIPs represented a small fraction. "Delayed enhancement" is characteristic to ordinary AIPs, however, "pancreatic-phase enhancement" is more diagnostic for atypical AIPs.

Osteoclast-like Giant Cell-type Pancreatic Anaplastic Carcinoma Presenting with a Duodenal Polypoid Lesion.

Osteoclast-like giant cell-type (OCGC) anaplastic carcinoma is a rare variant of pancreatic ductal adenocarcinoma, and its imaging characteristics and progression pattern have not been fully clarified. The patient was a 73-year-old man who had been incidentally found to have a pancreatic head tumor. Computed tomography demonstrated a 3-cm marginally enhanced mass at the pancreatic head, continuing toward the duodenum. Diffusion-weighted magnetic resonance imaging showed a retained diffusion capacity. Duodenoscopy revealed a 1.5-cm polypoid lesion, covered by a dirty coat, near the major papilla. Surgical material revealed OCGC pancreatic anaplastic carcinoma protruding to the duodenum, accompanied by multiple hemorrhagic foci and hemosiderin precipitations.

A Large Carcinosarcoma of the Gallbladder Accompanied by Pancreaticobiliary Maljunction: A Case with a Six-year Survival.

Pancreatobiliary maljunction (PBM) is a rare congenital malformation, often associated with adenocarcinoma. However, PBM accompanying gallbladder carcinosarcoma has rarely been reported. A 72-year-old woman was referred to our hospital, complaining of abdominal pain. Computed tomography showed a polypoid mass in the gallbladder. Endoscopic retrograde cholangiopancreatography showed PBM, and aspirated bile demonstrated elevated levels of pancreatic-type amylase (26,780 U/L) and cancer cells. Extended cholecystectomy was performed. Histologically, the tumor had adenocarcinoma, squamous cell carcinoma and sarcoma components. Despite the large tumor size (84 mm) and intra-vessel cancer permeations, this patient has been healthy for 73 months since the surgery.

A Splenic Epithelial Cyst: Increased Size, Exacerbation of Symptoms, and Elevated Levels of Serum Carcinogenic Antigen 19-9 after 6-year Follow-up.

A 58-year-old man, who had presented with a large cyst between the pancreatic tail and splenic hilum 6 years previously, was referred to our hospital with exacerbation of abdominal distention. Computed tomography revealed a well-demarcated, unilocular cyst, with a beak sign for the pancreas, without wall thickening or nodules suggestive of a non-neoplastic cyst. Compared with 6 years previously, the cyst had increased in size from 14.7 cm to 19.5 cm, and the serum carcinogenic antigen 19-9 level had increased from 635 U/mL to 1,918 U/mL. To prevent spontaneous rupture, laparotomy was performed, and the cyst was pathologically diagnosed as a splenic epithelial cyst.