Michael Cruise

Hepatic adenomas with synchronous or metachronous fibrolamellar carcinomas: both are characterized by LFABP loss.

Rare hepatic adenomas are associated with synchronous or metachronous fibrolamellar carcinomas. The morphology of these adenomas has not been well described and they have not been subclassifed using the current molecular classification schema. We examined four hepatic adenomas co-occurring with or preceding a diagnosis of fibrolamellar carcinoma in three patients. On histological examination, three of the adenomas showed the typical morphology of HNF1-α inactivated adenomas, whereas one showed a myxoid adenoma morphology. All of the adenomas were negative for PRKACA rearrangements by Fluorescence in situ Hybridization (FISH) analysis. All four of the adenomas showed complete loss or significant reduction of liver fatty acid binding protein (LFABP) expression by immunohistochemistry. Interestingly, the fibrolamellar carcinomas in each case also showed loss of LFABP by immunohistochemistry. One of the fibrolamellar carcinomas was negative for PRKACA rearrangements by FISH, whereas the others were positive. To investigate if LFBAP loss is typical of fibrolamellar carcinomas in general, an additional cohort of tumors was studied (n=19). All 19 fibrolamellar carcinomas showed the expected PRKACA rearrangements and immunostains showed loss of LFABP in each case, consistent with HNF1-α inactivation. To validate this observation, mass spectrometry-based proteomics was performed on tumor-normal pairs of six fibrolamellar carcinomas and showed an average 10-fold reduction in LFABP protein levels, compared with matched normal liver tissue. In conclusion, hepatic adenomas co-occurring with fibrolamellar carcinomas show LFABP loss and are negative for PRKACA rearrangements, indicating they are genetically distinct lesions. These data also demonstrate that LFABP loss, which characterizes HNF1-α inactivation, is a consistent feature of fibrolamellar carcinoma, indicating HNF1-α inactivation is an important event in fibrolamellar carcinoma pathogenesis.

Molecular testing for the clinical diagnosis of fibrolamellar carcinoma

Fibrolamellar carcinoma has a distinctive morphology and immunophenotype, including cytokeratin 7 and CD68 co-expression. Despite the distinct findings, accurate diagnosis of fibrolamellar carcinoma continues to be a challenge. Recently, fibrolamellar carcinomas were found to harbor a characteristic somatic gene fusion, DNAJB1–PRKACA. A break-apart fluorescence in situ hybridization (FISH) assay was designed to detect this fusion event and to examine its diagnostic performance in a large, multicenter, multinational study. Cases initially classified as fibrolamellar carcinoma based on histological features were reviewed from 124 patients. Upon central review, 104 of the 124 cases were classified histologically as typical of fibrolamellar carcinoma, 12 cases as ‘possible fibrolamellar carcinoma’ and 8 cases as ‘unlikely to be fibrolamellar carcinoma’. PRKACA FISH was positive for rearrangement in 102 of 103 (99%) typical fibrolamellar carcinomas, 9 of 12 ‘possible fibrolamellar carcinomas’ and 0 of 8 cases ‘unlikely to be fibrolamellar carcinomas’. Within the morphologically typical group of fibrolamellar carcinomas, two tumors with unusual FISH patterns were also identified. Both cases had the fusion gene DNAJB1–PRKACA, but one also had amplification of the fusion gene and one had heterozygous deletion of the normal PRKACA locus. In addition, 88 conventional hepatocellular carcinomas were evaluated with PRKACA FISH and all were negative. These findings demonstrate that FISH for the PRKACA rearrangement is a clinically useful tool to confirm the diagnosis of fibrolamellar carcinoma, with high sensitivity and specificity. A diagnosis of fibrolamellar carcinoma is more accurate when based on morphology plus confirmatory testing than when based on morphology alone.

Anaplastic lymphoma kinase positive large B-cell lymphoma: Literature review and report of an endoscopic fine needle aspiration case with tigroid backgrounds mimicking seminoma

Anaplastic lymphoma kinase‐positive large B‐cell lymphoma (ALK+ LBCL) is a rare distinct type of non‐Hodgkins lymphoma that arises in association with alterations of the ALK gene. This distinct disease entity is typically associated with an aggressive clinical course and appears in light microscopic preparations as a monomorphic population of large, immunoblast‐like cells. In this report, we describe a case of ALK+ LBCL diagnosed by transgastric endoscopic ultrasound‐guided fine needle aspiration (EUS FNA) of splenic hilar lymph nodes. Modified Giemsa stained direct smears from the FNA sample demonstrated large lesional cells with foamy cytoplasm and macronucleoli admixed with small lymphocytes in tigroid backgrounds, mimicking the cytologic appearance of seminoma. Ancillary immunohistochemical studies subsequently confirmed the diagnosis of ALK+ LBCL with the lesional cells being immunoreactive for CD138, VS38c, MUM1, ALK1, and lambda light chain. The cohesiveness of the cells, the cellular morphology, and the tigroid backgrounds were all pitfalls for accurate diagnosis of this rare specific type of lymphoid malignancy by cytology. To our knowledge this is the first case report detailing the diagnosis of ALK+ LBCL by EUS FNA and the first report describing a glycogen‐rich tigroid background in direct FNA smears. Establishing a refined diagnosis in cases of this rare form of LBCL is necessary, as therapies targeting ALK may be of value in clinical management. Diagn. Cytopathol. 2017;45:148–155.

Endoscopic ultrasound guided 22 gauge core needle biopsy for the diagnosis of Autoimmune pancreatitis

BACKGROUND It is difficult to obtain adequate tissue sample for diagnosing autoimmune pancreatitis (AIP) with the help of traditional EUS-guided FNA. As per ICDC guidelines, EUS-guided FNA is not recommended for diagnosing AIP(1). We herein present a report of 2 cases of using a new flexible 22 gauge (G) core biopsy needle (SharkCore, Medtronic, Sunnydale, Calif) for diagnosing AIP. METHODS This is a report of 2 cases reviewed retrospectively which had used 22G core biopsy needle for obtaining histo-pathological samples for diagnosing AIP. The cases were reviewed with both endoscopist and a pathologist to determine if the diagnostic criteria were met. RESULTS Both the cases had adequate tissue sample obtained to make a clear diagnosis of AIP. Pathology showed changes of chronic pancreatitis with atrophy and storiform pattern of fibrosis with a dense lymphoplasmacytic infiltrate in both cases along with identification of IgG4 cells. CONCLUSION EUS-guided fine needle biopsy (FNB) using the SharkCore needle can be used reliably for diagnosing AIP. More studies need to be performed to validate this further.

Simultaneous Clear Cell Sarcomas of the Duodenum and Jejunum

Clear cell sarcoma (CCS) is an uncommon tumor that usually presents as an extremity mass but can rarely manifest as a gastrointestinal tumor with a diverse spectrum of symptoms, most commonly related to a mass effect or ulceration. Herein we report a case in which two separate tumors, one in the duodenum and the other in the jejunum, present concurrently. The subject presented with symptomatic anemia and underwent imaging and endoscopic studies that culminated in the discovery of the two lesions. He subsequently underwent operative treatment with resection of both tumors and made an unremarkable recovery. The resection specimen consisted of two separate clear cell sarcomas with negative margins. Under microscopic evaluation, they demonstrated nested growths of epithelioid cells with scattered spindled cells infiltrating the enteric wall. The neoplastic cells were positive for S100 with scattered expression of Melan A. Florescence in situ hybridization revealed a translocation at the EWRS1 locus. He was disease-free for 30 months following the procedure; then he developed a rapidly progressing metastatic disease with subsequent death 4 months later.

Chronic cholecystitis with Cystoisospora belli in an immunocompetent patient

A 47-year-old woman presented with a history of vague abdominal pain for several years, which worsened over the past 2 months, with pain more prominent in the right upper quadrant. She also had a history of peptic ulcer disease. The ultrasound scan of right upper quadrant revealed normal gallbladder and oesophagogastroduodenoscopy was unremarkable. A 99mtechnetium labelled hepato iminodiacetic acid (HIDA) scan with cholecystokinin provocation demonstrated a decreased gallbladder ejection fraction (EF) of 32%. On this basis, the patient was diagnosed with biliary dyskinesia and underwent an elective laparoscopic cholecystectomy. Histopathological analysis revealed chronic cholecystitis with Cystoisospora belli identified in the gallbladder wall. Cystoisospora has been identified to cause an opportunistic acalculous cholecystitis among immunocompromised hosts, especially those with AIDS. This is the first case report of chronic cholecystitis due to C. belli in an immunocompetent patient.

Cancer-predicting transcriptomic and epigenetic signatures revealed for ulcerative colitis in patient-derived epithelial organoids

Ulcerative colitis (UC) is a prevalent form of inflammatory bowel disease (IBD) whose pathogenic mechanisms remain unclear. Elucidating these mechanisms is important to reduce UC symptoms and to prevent UC progression into colitis-associated colon cancer (CAC). Our goal was to develop and validate faithful, human-derived, UC models and analyze them at histologic, transcriptomic and epigenetic levels to allow mechanistic studies of UC and CAC pathogenesis. We generated patient-derived primary-organoid cultures from UC and non-IBD colonic epithelium. We phenotyped them histologically and used next-generation-sequencing approaches to profile whole transcriptomes and epigenomes of organoids and primary tissues. Tissue organization and expression of mucin 2 (MUC2) and lysozyme (LYZ) demonstrated histologic faithfulness of organoids to healthy and diseased colonic epithelium. Transcriptomic analyses showed increased expression of inflammatory pathways in UC patient-derived organoids and tissues. Profiling for active enhancers using the H3K27ac histone modification revealed UC-derived organoid enrichment for pathways indicative of gastrointestinal cancer, including S100 calcium-binding protein P (S100P), and revealed novel markers for GI cancer, including both LYZ and neuropeptide S receptor 1 (NPSR1). Immunolocalization showed increased levels of LYZ, S100P, and NPSR1 proteins in UC and CAC. In conclusion, primary colonic organoid cultures from UC and non-IBD patients can be established that faithfully represent diseased or normal colonic states. These models reveal precancerous molecular pathways that are already activated in UC. The findings demonstrate the suitability of primary organoids for dissecting UC and CAC pathogenic mechanisms and suggest new targets for therapeutic intervention.

Endoscopic ultrasound FNA: An illustrated review of spindle cell neoplasms of the upper gastrointestinal tract including a novel case of gastric plexiform fibromyxoma

Plexiform fibromyxoma (PF) is a recently‐described and rare mesenchymal neoplasm of the gastric wall. A few small case series reports of this spindle cell entity exist in the surgical pathology literature, but to our knowledge no prior endoscopic ultrasound guided fine needle aspiration cytology examples have been reported. In clinical practice, mural gastrointestinal (GI) lesions are often initially evaluated by endoscopic ultrasound guided (EUS) fine needle aspiration (FNA). In addition, newer EUS fine needle biopsy techniques also allow for reliable retrieval of core tissue samples with intact cellular architecture, making EUS histopathologic analyses possible. We report a combined EUS FNA and core biopsy case of PF and correlate the findings with imaging results. The cytomorphology of PF is described and illustrated, and important entities in the differential diagnosis of upper GI spindle cell lesions (including GI stromal tumor, leiomyoma, schwannoma, carcinoid tumor, desmoid‐type fibromatosis, and inflammatory fibroid polyp) are reviewed. Illustrated examples of relevant cytomorphologic, cell block histomorphologic and immunohistochemical characteristics are emphasized.

Pancreatic metastasis from an osseous solitary fibrous tumour

A 73-year-old man presented with a right-sided chest wall mass that showed an epitheloid neoplasm with mild cytologic atypia on core needle biopsy. He underwent surgical resection, and final pathology revealed solitary fibrous tumour/hemangiopericytoma with negative margins. Three years after surgical resection, the patient presented with fatigue, abdominal pain, weight loss and mildly elevated liver function tests. Further workup revealed a 1.2 cm hypervascular mass in the neck of the pancreas. This case report summarises the surgical treatment and outcomes for a patient who presented with this rare tumour.

Abstract A141: The vigorous immune microenvironment of microsatellite instable colon cancer isbalanced by multiple counter-inhibitory checkpoints

We examined the immune microenvironment of primary colorectal cancer (CRC) using immunohistochemistry, laser capture microdissection/qRT-PCR, flow cytometry and functional analysis of tumor infiltrating lymphocytes. A subset of CRC displayed high infiltration with activated CD8+ CTL as well as activated Th1 cells characterized by IFN-gamma production and the Th1 transcription factor Tbet. Parallel analysis of tumor genotypes revealed that virtually all of the tumors with this active Th1/CTL microenvironment had defects in mismatch repair, as evidenced by microsatellite instability (MSI). Counterbalancing this active Th1/CTL microenvironment, MSI tumors selectively demonstrated highly up-regulated expression of multiple immune checkpoints, including five - PD-1, PD-L1, CTLA-4, LAG-3 and IDO - currently being targeted clinically with inhibitors. These findings link tumor genotype with the immune microenvironment, and explain why MSI tumors are not naturally eliminated despite a hostile Th1/CTL microenvironment. They further suggest that blockade of specific checkpoints may be selectively efficacious in the MSI subset of CRC. Our findings are the first to demonstrate a link between a genetically defined subtype of cancer and its corresponding expression of immune checkpoints in the tumor microenvironment. The mismatch repair defective subset of CRC selectively up-regulates at least 5 checkpoint molecules that are targets of inhibitors currently being clinically tested. Furthermore, our results were clinically validated in a phase 2 study at Hopkins which showed mismatch-repair status as a predictor of clinical benefit to immune checkpoint blockade with pembrolizumab. Citation Format: Nicolas J. Llosa, Franck Housseau, Elizabeth Wick, Hechenbleikner Lizzy, Michael Cruise, Robert Anders, Cynthia Sears, Drew M. Pardoll, Hongni Fan, Nicholas Siegel, Lee Blosser, Ada Tam, Hao Wang. The vigorous immune microenvironment of microsatellite instable colon cancer isbalanced by multiple counter-inhibitory checkpoints. [abstract]. In: Proceedings of the CRI-CIMT-EATI-AACR Inaugural International Cancer Immunotherapy Conference: Translating Science into Survival; September 16-19, 2015; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2016;4(1 Suppl):Abstract nr A141.