Does a Positive Appendiceal Resection Margin in Low-Grade Appendiceal Mucinous Neoplasms, Warrant Additional Surgery? Our Institution Experience and Literature Review.

BACKGROUND: Management of low-grade appendiceal mucinous neoplasm (LAMN) with positive resection margin is controversial. Some guidelines recommend surgical reexcision, whereas others recommend a conservative approach. The purpose of our study was to determine whether involvement of the resection margin by LAMN is a risk factor for local recurrence requiring additional surgery. DESIGN: This is a retrospective study (January 2000-December 2020) of uncomplicated LAMNs with neoplastic epithelium or dissecting mucin at the resection margin. For cases treated with additional surgery, the presence of residual tumor was evaluated. Clinical follow-up was attained in all cases. We also conducted a literature review. RESULTS: The study investigated 98 patients. Eight with median age of 67 (range: 45-91) years had a LAMN involving the resection margin (8.2%). Five of eight LAMNs (62.5%) with neoplastic epithelium at the margin underwent surgery, and no residual neoplasm was identified. The other three cases were followed conservatively, and no patient developed recurrence (follow-up: 18-69 months with a mean of 45 months). In a review of the literature, we identified 52 LAMNs with positive margin. Although three cases had acellular mucin and one residual LAMN in the reexcision specimen (7.7%), neither of these four cases or any of the other 46 followed conservatively had recurrence of disease. CONCLUSIONS: These data suggest that for patients with uncomplicated LAMN confined to the appendix, the involvement of the appendiceal margin does not necessary lead to recurrence of LAMN, and a conservative management is a reasonable alternative.

Solitary fibrous tumor occurring in the colon as submucosal mesenchymal lesion: report of two cases and review of the literature.

Solitary fibrous tumor (SFT) is a rare mesenchymal neoplasm most often arising from the pleura and rarely in extra-pleural locations, including the gastrointestinal tract. We describe two cases of a SFT presenting as submucosal colonic lesion and review the literature on this lesion. One submucosal lesion was localized in the cecum and was 10 mm in size. The second lesion presented as a 17 mm submucosal rectal lesion. Both lesions presented as well-circumscribed submucosal lesions arranged in short fascicles, blending with abundant collagenous stroma. In both cases, the spindle cells were positive for CD34, STAT6 and CD99, and molecular studies showed NAB2:STAT6 fusion supporting the diagnosis of SFT. Both patients are alive and well 10 and 5 years post-excision, respectively. In conclusion, SFT can occur in the colon as a submucosal lesion and should be included in the differential diagnosis of colonic mesenchymal lesions.

Gastroblastoma with a novel ACTB::GLI1 gene fusion in a 19-year-old male.

Gastroblastoma is a rare gastric biphasic tumor composed of mesenchymal and epithelial elements in variable proportions. These tumors usually arise in the gastric antrum of children and young adults and are reported to harbor a recurrent MALAT1::GLI1 fusion. Herein we report a case of gastroblastoma in a 19-year-old male who presented with intermittent epigastric abdominal discomfort. Antrectomy revealed a 5.6-cm multi-lobulated, tan-pink mass with solid and focally cystic areas involving the submucosa, muscularis propria, and subserosa. All tumor cells demonstrated immunoreactivity for GLI-1, CD56, and vimentin; epithelial elements expressed pancytokeratins (AE1/AE3 and Oscar), and mesenchymal cells demonstrated focal positivity for CD10. Next generation sequencing revealed a novel ACTB::GLI1 fusion without evidence of the recurrent MALAT1::GLI1 fusion. Nine months after surgery, the patient is well without evidence of recurrence or metastases. To our knowledge, this is the first case of gastroblastoma harboring this novel ACTB::GLI1 fusion.

Blastomas of the digestive system in adults: A review.

Blastomas, characterized by a mixture of mesenchymal, epithelial, and undifferentiated blastematous components, are rare malignant neoplasms originating from precursor blast cells. This review focuses on digestive system blastomas in adult patients, including gastroblastoma, hepatoblastoma, and pancreatoblastoma. Gastroblastoma is a biphasic, epitheliomesenchymal tumor, with only sixteen cases reported to date. In addition to the characteristic histology, metastasis-associated lung adenocarcinoma transcript 1 - glioma-associated oncogene homolog 1 gene fusion is typical, although recently novel ewing sarcoma breakpoint region 1 - c-terminal binding protein 1 and patched 1 - glioma-associated oncogene homolog 2 fusions have been described. Hepatoblastoma is exceptionally rare in adults and can show a variety of histologic patterns which may cause diagnostic difficulty. Pancreatoblastoma, primarily a pediatric tumor, displays acinar differentiation and squamoid nests with other lines of differentiation also present, especially neuroendocrine. Diagnostic approaches for these blastomas include a combination of imaging modalities, histopathological examination, and molecular profiling. The treatment generally involves surgical resection, which may be supplemented by chemotherapy or radiotherapy in some cases. Prognoses vary with gastroblastoma generally showing favorable outcomes post-surgery whereas hepatoblastoma and pancreatoblastoma often have poorer outcomes, particularly in the setting of metastases. This review highlights the complexity of diagnosing and managing these rare adult blastomas as well as the need for ongoing research to better understand their pathogenesis and improve treatment strategies.

Corrigendum to "Localized Biphasic Malignant Peritoneal Mesothelioma with Rhabdoid Features Involving the Liver: Case Report and Review of the Literature".

[This corrects the article DOI: 10.1155/2019/2732674.].

Paraganglia of the Gallbladder: An Underrecognized Incidental Finding and Potential Diagnostic Pitfall.

CONTEXT.­: The identification of paraganglia (PG) in the gallbladder (GB) is infrequent, and easily overlooked as it is not something routinely reported. Occasionally they may be misinterpreted as neoplastic cells, such as low-grade carcinomas, germ cell tumors, or because of their close resemblance to neuroendocrine cells, as low-grade neuroendocrine neoplasms. OBJECTIVE.­: To evaluate the incidence and histological features of PG of the GB in patients that underwent cholecystectomy, and discuss the potential misinterpretation of these benign structures as clusters of neoplastic cells. DESIGN.­: A retrospective study of cholecystectomy specimens performed during a 6-month period were reviewed for identification of PG. Immunohistochemical studies for chromogranin, synaptophysin, S100, and cytokeratin AE1/AE3 were performed in selected cases. RESULTS.­: A total of 365 GBs were reviewed and in 16 cases (4.4%) PG was identified within the subserosal connective tissue of the GB wall or cystic duct adjacent to small capillaries, nerves, and ganglia. They consisted of well-demarcated, lobular structures ranging in size from 0.2 to 0.5 cm, which were predominantly composed of chief cells, with strong expression for chromogranin and synaptophysin and negative CKAE1/AE3, and a minor component of S100-positive sustentacular cells. CONCLUSIONS.­: PG is an uncommon finding with a prevalence of 4.4% in our study. Awareness of their location, histologic features, and immunohistochemical profile may help practicing pathologists to confirm their benign nature, avoid a misdiagnosis of malignancy, and prevent unnecessary diagnostic work-up and treatment.

Intraductal tubulopapillary neoplasms of the pancreas and biliary tract: The black swan of hepatobiliary surgery.

Intraductal tubulopapillary neoplasms (ITPNs) of the pancreas and biliary tract are rare pre-malignant entities of the biliary tract and pancreas that are difficult to diagnose preoperatively. While there are imaging characteristics that can differentiate these lesions from more common entities like adenocarcinoma or intraductal papillary mucinous neoplasms (IPMN), ITPNs are not always distinctive. Herein we present two cases of ITPN, one of biliary and the other of pancreatic origin, which had a preoperative diagnosis of cholangiocarcinoma and IPMN, respectively. We discuss our findings in these cases, patient presentation and course, review the radiographic and pathologic findings, and propose a more effective approach to the preoperative workup and diagnosis of ITPN based on our review of the contemporary literature.

Gastric Desmoid Fibromatosis - Report of a Rare Mimic of Gastrointestinal Stromal Tumor.

Desmoid fibromatosis (DF) involving the gastrointestinal tract is extremely rare. Its intramural location and occasional expansile growth pattern within the bowel wall may mimic a gastrointestinal stromal tumor (GIST). Due to the different disease behaviors and management, it is important to make a correct diagnosis before further treatment. We present an extremely rare case of a gastric DF that on imaging appeared as a discrete intramural mass mimicking a GIST and that was preoperatively correctly diagnosed as a DF based on its cytomorphologic, immunohistochemical, and molecular profiles. The patient is a 71-year-old female who presented with dysphagia and unintentional weight loss. A mass was identified at the gastric fundus. Endoscopic ultrasound-guided fine-needle aspirate (FNA) and biopsy (FNB) were performed. The FNA showed a few small aggregates of cytologically bland spindle-shaped cells with elongated nuclei. The FNB yielded small fragments of tissue composed of bland spindle cells demonstrating nuclear and cytoplasmic immunostain for ß-catenin and focal stain for smooth muscle actin (SMA) and desmin. CD117, DOG1, CD34, caldesmon, S100, cytokeratin AE1/AE3, signal transducer and activator of transcription 6 (STAT6), MUC4, progesterone receptor (PR), and anaplastic lymphoma kinase (ALK) were negative, and MIB-1 showed a very low proliferation activity index. Molecular studies performed by targeted next-generation sequencing showed activating mutations in CTNNB1. These results excluded a GIST and confirmed the diagnosis of a gastric DF. Although it is very rare, DF must be included in the differential diagnosis of discrete intramural gastric spindle cell lesions. A definitive diagnosis can be made preoperatively if enough lesional material is available for appropriate immunohistochemical and molecular studies.

Utility and Limitations of Albumin mRNA In Situ Hybridization Detection in the Diagnosis of Hepatobiliary Lesions and Metastatic Carcinoma to the Liver.

Albumin messenger RNA (mRNA) in situ hybridization is a sensitive and specific biomarker for hepatocellular carcinoma (HCC). Intrahepatic cholangiocarcinoma (ICC) shows variable sensitivity, whereas extrahepatic cholangiocarcinoma (ECC) and metastatic carcinoma are generally negative. We studied the clinical utility and limitations of albumin mRNA detection in a cohort of HCCs, ICCs, ECCs, bile duct adenomas, bile duct hamartomas, and metastatic carcinomas to the liver; and investigated the variability in sensitivity observed for this biomarker in ICCs. We identified 122 cases of hepatobiliary lesions and metastatic carcinomas. Albumin mRNA detection was performed using RNAscope run on formalin-fixed, paraffin-embedded tissue sections. ICCs were categorized according to the classification proposed by Hayashi and colleagues into the small duct, large duct, and indeterminate subtypes. Albumin mRNA was detected in all 17 HCCs and focally in 6/8 (75%) of bile duct adenomas. All 28 nonhepatic carcinomas, 13 bile duct hamartomas, and 9 ECCs were negative. Albumin mRNA was found in 38/47 (80.9%) of ICC with 35/37 (94.6%) in the small duct subtype, 2/3 (66.7%) in the indeterminate subtype, and 1/7 (14.3%) of the large duct subtype (P<0.003). Albumin mRNA detection is a sensitive and specific biomarker for HCCs. It is highly sensitive and moderately specific in the diagnosis of ICC with small gland morphology, but not ICCs with large duct morphology and in metastatic carcinoma. The variability in the sensitivity of albumin mRNA expression in ICCs may depend on the subtypes of ICC.

Drug and herbal/dietary supplements-induced liver injury: A tertiary care center experience.

BACKGROUND: Drug-induced liver injury (DILI) and herbal/dietary supplements (HDS) related liver injury present unique diagnostic challenges. Collaboration between the clinician and the pathologist is required for an accurate diagnosis and management. AIM: To report our experience on the clinical-pathological findings of hepatic injury caused by drugs/HDS. METHODS: A retrospective review of clinically proven cases of DILI/HDS who presented to our institution from January 1, 2013 to December 31, 2017 was performed. Slides were reviewed for histopathological patterns of injury and correlated with the causative agent. Out of 600 patients presenting with unexplained rise in liver enzymes undergoing biopsy, 107 were suspected to have DILI/HDS. Of these, 53 had a directly linked exposure to drug/herbal supplements. Fifteen patients were excluded for concurrent known liver disease. Thirty-eight patients with clinically proven DILI/HDS were finally included. RESULTS: Thirty-eight cases of DILI/HDS with a male:female of 1:1.5 and mean age of 51 ± 3 years were identified. DILI was identified in 84.2% cases while HDS injury in 15.8%. Acute hepatitis (42.1%) was the most common pattern of injury while granulomatous hepatitis (2.6%) was the least common. We found one case of acute-cholestasis due to rivaroxaban and two cases of cholestatic-hepatitis due to rizatriptan and trimethobenzamide-hydrochloride that, to the best of our knowledge, have not been previously reported. One case of steatohepatitis due to trimethoprim-sulfamethoxazole and three unusual cases of cholestatic-hepatitis with bile duct injury and steatosis due to dronedarone, C4-Extreme and hydroxycut, were also seen. Of our cohort, 81.6% of the patients fared well with discontinuation of drug and 18.4% underwent transplant; of which 42.9% were deceased. CONCLUSION: We describe the clinical findings, histopathological patterns of injury and clinical outcomes caused by drugs. In particular, we report a few previously unreported/ rarely observed clinical and histopathological patterns of hepatic injury.

Localized Biphasic Malignant Peritoneal Mesothelioma with Rhabdoid Features Involving the Liver: Case Report and Review of the Literature.

INTRODUCTION: Localized malignant mesotheliomas, defined as sharply circumscribed tumors of the serosal membrane with the microscopic appearance of diffuse malignant mesothelioma, are rare tumors; their behavior and prognosis are uncertain. Intrahepatic mesotheliomas are postulated to arise from mesothelial cells of Glisson's capsule. CASE PRESENTATION: A 69-year-old female with no history of asbestos exposure presented with a one-month history of increasing abdominal pain associated with constitutional symptoms. Computerized Tomography (CT) scan of the abdomen and pelvis revealed a sizable soft tissue mass within the right paracolic gutter, abutting the inferior hepatic margin, the lateral abdominal wall, and descending colon. Ultrasound-guided biopsy of the mass suggested a poorly differentiated hepatocellular carcinoma. There was no disease elsewhere on PET scan. Surgical resection of the mass was performed. Pathological assessment suggested the tumor to be arising from the liver with invasion of the liver, abdominal wall musculature, and the adventitial surface of the ascending colon. A final diagnosis of localized biphasic malignant peritoneal mesothelioma with rhabdoid features was rendered based on morphology and the result of immunohistochemical studies. The abdominal wall margin was positive. The patient progressed over the course of 6 months despite receiving adjuvant chemotherapy and immunotherapy with metastases and a decline in performance status and was transitioned to hospice. CONCLUSION: Localized malignant peritoneal mesotheliomas are rare tumors that may present clinically as a liver mass and simulate primary hepatic or secondary tumors. Definitive diagnosis is obtained by surgical resection in most cases. The clinical outcome is variable with most cases having a poor outcome.

Duodenal Epithelial Polyps: A Clinicopathologic Review.

CONTEXT.­: Duodenal epithelial polyps are reported in 1.5% to 3% of individuals referred for upper endoscopy. Most duodenal epithelial polyps are asymptomatic and nonneoplastic; however, a small subset is neoplastic and may progress to adenocarcinoma. Recent advances in immunohistochemical and molecular techniques have helped further characterize these polyps, shedding light on their origin, classification, and risk of progression to adenocarcinoma. OBJECTIVE.­: To provide a comprehensive clinicopathologic review of nonneoplastic and neoplastic duodenal epithelial polyps, with particular emphasis on recent developments in classification schemes and risk stratification based upon immunohistochemical and molecular profiles. DATA SOURCES.­: This review is based on peer-reviewed literature and the authors' experiences. CONCLUSIONS.­: In this review we provide an update on the clinicopathologic, immunohistochemical, and molecular features of duodenal epithelial polyps and discuss the surveillance recommendations and treatment options available. Particular attention should be placed on recognizing duodenal adenomas with intestinal, gastric, and serrated phenotype, as they have an increased risk of malignant transformation if not completely excised.

A large inflammatory fibroid polyp of the rectum removed by transanal excision.

Inflammatory fibroid polyps (IFP) are rare benign lesions arising from the submucosa of the gastrointestinal tract, most commonly found in the stomach and small intestine. IFPs are very rarely found in the rectum, with only a few reported cases, and their presentation is quite varied. The patient is a 53 year old male who underwent routine screening colonoscopy, during which a lobular mass of the proximal rectum was discovered. The patient subsequently underwent an endoscopic ultrasound (EUS) with fine needle aspiration (FNA) biopsy. Pathology displayed scant spindle cells with benign glandular epithelium suspicious for a spindle cell neoplasm. The mass was excised transanally. The morphological and immunohistochemical findings supported the diagnosis of inflammatory fibroid polyp. Although this is not a malignant tumor, the treatment and surveillance guidelines have not been determined and there is no standard of care.

S100A4 protein and mesothelin expression in dysplasia and carcinoma of the extrahepatic bile duct.

We evaluated the expression of S100A4 protein and mesothelin in dysplasia and carcinoma of the extrahepatic bile duct (EBD) and their potential use as adjuncts for differentiating carcinomatous and significant high-grade dysplastic epithelium from reactive or inflammatory glandular atypia of the EBD. We used immunohistochemical analysis on formalin-fixed tissue sections from 10 cases of carcinoma, 6 cases of high-grade dysphasia (HGD), 4 cases of low-grade dysplasia (LGD), and 10 cases of benign or reactive or inflammatory epithelium from the EBD. Expression of S100A4 protein was observed in 8 invasive carcinomas (80%), 5 HGD/carcinoma in situ cases (83%), and 0 LGDs. Mesothelin was expressed in 5 (50%) of 10 adenocarcinomas, 1 (17%) of 6 HGD/adenocarcinoma in situ cases, and 0 LGDs. No case of normal or reactive epithelium was positive for S100A4 protein or mesothelin. Mesothelin has moderate sensitivity and high specificity, whereas S100A4 protein is sensitive and specific for the identification of carcinoma and HGD of the EBD. S100A4 protein alone or combined with mesothelin can be used as an adjunct in differentiating carcinomatous and significant high-grade dysplastic epithelium from LGD and reactive or inflammatory glandular atypia of the EBD.

Expression of K homology domain containing protein overexpressed in cancer in pancreatic FNA for diagnosing adenocarcinoma of pancreas.

We evaluated the immunocytochemical (ICC) expression of K homology domain containing protein overexpressed in cancer (KOC) in pancreatic endoscopic ultrasound-guided fine needle aspirates (EUS-FNAs) to assess its potential use as an adjunct in differentiating nonneoplastic (GI epithelium) and benign neoplastic epithelia (benign epithelial pancreatic neoplasms) from pancreatic adenocarcinoma cells. Forty-eight cases of EUS-FNAs with histological and/or clinical follow-up data were selected for this study. Alcohol-fixed and PAP-stained slides were stained with monoclonal antibody to KOC/L523S (clone 69.1). Results were recorded as negative or positive. KOC expression was present in 35/40 (88%) of adenocarcinomas (Ac) and was negative in all eight benign cases. The sensitivity and specificity were as follows: cytology 85 and 100%, KOC 88 and 100%; combination of cytology and KOC 95 and 100%. We conclude that KOC ICC expression on alcohol-fixed smears along with cytology improves the sensitivity of EUS-FNAs in the diagnosis of pancreatic Ac, and KOC reactivity is especially useful in differentiating Ac from nonneoplastic gastrointestinal epithelium and benign neoplastic epithelia.

Identification of Signet Ring Cell Change in Colonic Subserosa in the Setting of Clostridium difficile Colitis.

Signet ring cell change of intestinal epithelial cells is a rare but well-known mimicker of signet ring cell carcinoma and is often associated with ischemic and/or pseudomembranous colitis. Instead, signet ring cell change involving nonepithelial cells in the subserosa of the intestine is an extremely rare finding with only a single case report in the literature to date. We report a new case of benign signet ring cell change localized in the subserosa of the large bowel incidentally identified in a resection specimen for Clostridium difficile colitis mimicking a metastatic signet ring cell carcinoma. Based on the morphologic features and immunohistochemical profile, we propose that these signet ring cells may possibly represent modified/degenerated fat cells. Furthermore, we discuss how to differentiate benign signet ring cells from a signet ring cell carcinoma.

IMP3 Immunoreactivity is More Sensitive Than AMACR in Detecting Dysplastic Epithelium and Early Adenocarcinoma in Barrett Esophagus.

CONTEXT: α-methylacyl coenzyme A racemase (AMACR) and insulin-like growth factor-II mRNA-binding protein 3 (IMP3) are 2 markers helpful in detecting difficult cases of dysplasia in Barrett esophagus (BE). However, no comparison studies have been performed to assess their performance in the same patient population. OBJECTIVES: The aim of our study was to compare the immunohistochemical expression of IMP3 and AMACR in dysplastic lesions and early adenocarcinoma (EAC) arising in BE and evaluate their sensitivity and specificity. DESIGN: A total of 98 cases [BE negative for dysplasia, n=24; indefinite for dysplasia (BE-IND), n=18; low-grade dysplasia (LGD), n=24; high-grade dysplasia (HGD), n=16; and EAC, n=16] were immunostained for AMACR and IMP3 and evaluated for the degree, the extent, and the intensity of staining. RESULTS: No immunoreactivity for AMACR or IMP3 was observed in all 24 cases of BE negative for dyplasia. One of 18 (5.5%) cases of BE-IND was positive for IMP3, but all were negative for AMACR. AMACR and IMP3 were positive in 16.7% versus 41.7 % of the cases with BE-LGD, 25% versus 62.5% of BE-HGD, and 62.5% versus 93.7% of EAC, respectively. The sensitivity of AMACR and IMP3 for the detection of dysplasia in BE is 16.7% and 41.7% for LGD, 25% and 62.5% for HGD, and 62.5% and 93.7% in EAC, respectively. The specificity is 100% for both markers. In addition, a comparison of the intensity of reactivity shows a better result with IMP3 (36/98, 36.7%) than with AMACR (18/98, 18.4%) (P<0.001). CONCLUSIONS: IMP3 has a similar specificity, but a better sensitivity, intensity, and extent of reactivity in comparison with AMACR, and may be used as an alternative to AMACR, in support of the diagnosis of BE-dysplasia and EAC.

Perivascular Epithelioid Cell Tumor (PEComa) of Pancreas Diagnosed Preoperatively by Endoscopic Ultrasound-Guided Fine-Needle Aspiration: A Case Report and Review of Literature.

Perivascular epithelioid cell tumors (PEComas) of the pancreas are extremely rare mesenchymal tumors and to our knowledge, only 17 cases have been reported in the English literature to date. We report our experience with a new case of primary pancreatic PEComa diagnosed preoperatively by endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) complemented by tissue cell block and immunohistochemistry. The patient was a 54-year-old female whose chief complaint was intermittent severe right upper quadrant abdominal pain. Computed-tomography (CT) imaging revealed a mass between the head and the body of the pancreas. EUS-FNA smear preparation was obtained but was nondiagnostic. However, examination of the tissue cell block showed sheets of epithelioid cells with abundant eosinophilic cytoplasm and immunohistochemistry studies revealed positivity for both melanocytic (HMB-45 and Melan-A) and smooth muscle markers (actin and desmin). A diagnosis of PEComa was made and an uncomplicated middle pancreatectomy was performed. Our case and review of the literature demonstrates that EUS-FNA complemented with tissue cell block increases cellular yield, improved preoperative diagnostic accuracy, and may assist the surgeon in planning conservative surgical management. Diagn. Cytopathol. 2017;45:59-65. © 2016 Wiley Periodicals, Inc.