Divergent Lineage Markers in Anaplastic Thyroid Carcinoma.

Anaplastic thyroid carcinoma (ATC) often results from dedifferentiation of differentiated thyroid carcinoma (DTC), and the diagnosis is not difficult, as the tumor is seen to progress from a recognized DTC. However, in some cases, the diagnosis based on biopsy of limited tissue or resection of a completely undifferentiated tumor relies on immunohistochemical biomarkers and is usually a diagnosis of exclusion. To examine the biomarker profile of ATC and to determine whether divergent lineage markers can complicate this process, we examined the expression of a number of biomarkers in a series of ATCs. Cases retrieved from the department laboratory information system were included if there was evidence of an accurate diagnosis based on the presence of a coexisting or antecedent DTC or in cases where the immunoprofile was consistent with thyroid origin in a non-equivocal clinical setting. Questionable cases were excluded. We identified 36 cases for analysis. Tissue sections were stained for PAX8, TTF1, BRAFV600E, NRASQ61R, TRK, and p53, as well as p40, CDX2, SATB2, GATA3, CD117, CD163, SALL4, SMARCA4, PRAME, SOX10, ERG and HEPPAR1. As expected, all 36 ATCs were negative for TTF1 except for one showing focal, weak expression. Thirteen expressed PAX8 with variable intensity. BRAFV600E was positive in 10/34 tumors and equivocal in 3; NRASQ61R was positive in 12, and TRK was positive in 1 case. Staining for p53 was diffusely positive in 14 and completely negative in 19, with only 3 cases showing a wild-type pattern. We found aberrant expression of GATA3 in 11/36 cases, SATB2 in 8/36, CD117 in 2/35, and SALL4 in 1/30. CD163 expression was identified in tumor cells in 10/30 cases with variable intensity; in the other tumors, interpretation was obscured by abundant histiocytes. P40 was positive in 5 cases with squamoid morphology. CDX2 was negative in 35 tested cases. PRAME was identified in 1 of 33 cases. Stains for SOX10, ERG, and HEPPAR1 were negative in 33 cases. Twenty tested cases showed retained SMARCA4 expression. We conclude that ATCs express a number of divergent lineage markers that can cause diagnostic dilemmas, as they are also features of other tumors in the differential diagnosis of high-grade midline neck malignancies.

The adherence to the American Association for the Study of Liver Diseases 2018 guidelines in the management of hepatocellular carcinoma and its impact on survival.

Introduction: In two Korean and Italian studies, the adherence rate (AR) to ASSLD 2005 guidelines in the management of hepatocellular carcinoma (HCC) was 60%. In a US study, the AR to American Association for the Study of Liver Disease (AASLD) 2005 guidelines was 73.3%, 26.8%, 25.3%, and 58.8% for patients with Barcelona Clinic Liver Cancer (BCLC) Stage A, B, C, and D, respectively, and nonadherence to guidelines was associated with longer overall survival (OS) in patients with BCLC Stage D. Here, we explored the AR to AASLD 2018 guidelines and its impact on OS. Methods: Between 2017 and 2019, 148 unique treatment-naïve patients with HCC were identified. Patients were staged according to the BCLC staging system and their AR to AASLD 2018 guidelines was noted. OS was estimated using Kaplan-Meier method. Survivals among patients from different groups was compared using Log-rank test. Results: The overall AR to AASLD 2018 guidelines was 83%. The AR for BCLC Stages 0, A, B, C, and D were 100%, 97%, 77%, 77%, and 38%, respectively. In patients with BCLC Stage D, the OS of patients treated with modalities adherent versus nonadherent to AASLD 2018 guidelines was 0.03 vs. 5.2 months (P = 0.0005). Otherwise, adherence versus nonadherence to AASLD 2018 guidelines showed no statistically significant differences in OS for patients with BCLC Stages 0, A, B, and C. Conclusion: The overall AR to AASLD 2018 guidelines was 83%. Nonadherence to AASLD 2018 guidelines in patients with BCLC Stage D translated into better OS.

Discordance Between Conventional and Detailed Lymph Node Analysis in Resected, Node-negative Pancreatic or Ampullary Adenocarcinomas and Association With Adverse Survival Outcomes: A Single-institution Analysis.

OBJECTIVE: To assess the frequency of occult metastases (OM) in patients with resected pancreatic ductal adenocarcinoma (PDAC) or ampullary adenocarcinoma (AA) discovered on detailed pathologic examination on lymph nodes (LNs) previously considered negative by conventional analysis and to examine the association between OM and overall survival (OS). BACKGROUND: Poor prognosis of patients with no pathologic evidence of LN metastases may be due to OM that is not detected on conventional LN analysis. METHODS: Patients with LN-negative resected PDAC or AA (2010-2020) were identified from our institutional database. Original hematoxylin and eosin ( H and E ) slides were reanalyzed. In addition, selected LN were analyzed by H and E (3 sections/LN) and pan-cytokeratin (AE1-AE3/PCK26) immunohistochemistry. RESULTS: A total of 598 LNs from 74 LN-negative patients were reexamined. Nineteen patients (25.7%) had OM; 9 (47.4%) were found with immunohistochemistry but not on H and E . The number of positive LNs ranged from 1 to 3. No clinicodemographic, pathologic, or treatment-related factors were associated with OM. On conventional LN analysis, 3/19 patients (15.8%) had stage IA, 9/34 (26.5%) had stage IB, and 7/19 (36.8%) had stage IIA. On detailed LN analysis, 11/19 patients (57.9%) were upstaged to IIB, whereas 8/19 (42.1%) had isolated tumor cells only (N0i+). OM was associated with shorter OS (median OS: 22.3 vs 50.5 months; hazard ratio=3.95, 95% CI: 1.58-9.86). CONCLUSIONS: There is a 26% discordance rate between conventional and detailed LN pathologic analysis in resected PDAC and AA. The presence of OM is associated with shorter OS.

Retinoblastoma Expression and Targeting by CDK4/6 Inhibitors in Small Cell Lung Cancer.

The canonical model of "small cell lung cancer" (SCLC) depicts tumors arising from dual inactivation of TP53 and RB1. However, many genomic studies have persistently identified tumors with no RB1 mutations. Here, we examined RB1 protein expression and function in SCLC. RB1 expression was examined by IHC analysis of 62 human SCLC tumors. These studies showed that ∼14% of SCLC tumors expressed abundant RB1 protein, which is associated with neuroendocrine gene expression and is enriched in YAP1 expression, but no other lineage proteins that stratify SCLC. SCLC cells and xenograft tumors with RB1 protein expression were sensitive to growth inhibition by the CDK4/6 inhibitor palbociclib, and this inhibition was shown to be dependent on RB1 expression by CRISPR knockout. Furthermore, a patient with biopsy-validated wild-type RB1 SCLC who received the CDK4/6 inhibitor abemaciclib demonstrated a dramatic decrease in mutant TP53 ctDNA allelic fraction from 62.1% to 0.4% and decreased tumor mass on CT scans. Importantly, IHC of the diagnostic biopsy specimen showed RB1 positivity. Finally, we identified a transcriptomics-based RB1 loss-of-function signature that discriminates between SCLC cells with or without RB1 protein expression and validated it in the patient who was responsive to abemaciclib, suggesting its potential use to predict CDK4/6 inhibitor response in patients with SCLC. Our study demonstrates that RB1 protein is an actionable target in a subgroup of SCLC, a cancer that exhibits no currently targetable mutations.

Ablation of PDE4B protects from Pseudomonas aeruginosa-induced acute lung injury in mice by ameliorating the cytostorm and associated hypothermia.

Pseudomonas aeruginosa is a frequent cause of hospital-acquired lung infections characterized by hyperinflammation, antibiotic resistance, and high morbidity/mortality. Here, we show that the genetic ablation of one cAMP-phosphodiesterase 4 subtype, PDE4B, is sufficient to protect mice from acute lung injury induced by P aeruginosa infection as it reduces pulmonary and systemic levels of pro-inflammatory cytokines, as well as pulmonary vascular leakage and mortality. Surprisingly, despite dampening immune responses, bacterial clearance in the lungs of PDE4B-KO mice is significantly improved compared to WT controls. In wildtypes, P aeruginosa-infection produces high systemic levels of several cytokines, including TNF-α, IL-1ß, and IL-6, that act as cryogens and render the animals hypothermic. This, in turn, diminishes their ability to clear the bacteria. Ablation of PDE4B curbs both the initial production of acute response cytokines, including TNF-α and IL-1ß, as well as their downstream signaling, specifically the induction of the secondary-response cytokine IL-6. This synergistic action protects PDE4B-KO mice from the deleterious effects of the P aeruginosa-induced cytostorm, while concurrently improving bacterial clearance, rather than being immunosuppressive. These benefits of PDE4B ablation are in contrast to the effects resulting from treatment with PAN-PDE4 inhibitors, which have been shown to increase bacterial burden and dissemination. Thus, PDE4B represents a promising therapeutic target in settings of P aeruginosa lung infections.

The impact of neoadjuvant concurrent chemoradiation on exosomal markers (CD63 and CD9) expression and their prognostic significance in patients with rectal adenocarcinoma.

INTRODUCTION: Exosomes have pivotal roles in cancer development. The impact of neoadjuvant concurrent chemoradiation (NCCR) on exosomal markers (CD63 and CD9) expression and their prognostic significance in patients with rectal adenocarcinoma are yet to be explored. MATERIALS AND METHODS: Between 2015 and 2018, 33 patients had rectal adenocarcinoma treated with NCCR and had pre-NCCR biopsy and post-NCCR resected rectum. CD63 and CD9 expression was assessed by immunohistochemistry (IHC). The short-term surrogate endpoint neoadjuvant rectal (NAR) score was used for assessment of prognostic significance. Un-Paired t-test was used for statistical analysis. RESULTS: The mean tumor CD63 and CD9 scores in pre-NCCR biopsy vs. post-NCCR resected rectum were 106 vs. 165 (P = 0.0022) and 136 vs. 215 (P < 0.0001) respectively. The mean tumor CD63 and CD9 scores respectively in pre-NCCR biopsy was 99 and 130 in patients with low-intermediate NAR score compared to 117 and 144 in patients with high NAR score (P = 0.4934) (P = 0.5519). The mean tumor CD63 and CD9 scores respectively in post-NCCR resected rectum was 155 and 205 in patients with low-intermediate NAR score compared to 180 and 230 in patients with high NAR score (P = 0.3793) (P = 0.2837). CONCLUSIONS: The expression of the exosomal markers (CD63 and CD9) increased in patients with rectal adenocarcinoma after treatment with NCCR. The exosomal markers (CD63 and CD9) may have a prognostic significance. There was a trend for higher CD63 and CD9 expression in patients with high NAR score compared with low-intermediate NAR scores. The lack of statistical significance is likely due to the small sample size.

Clinicopathologic Characteristics of Young Patients with Oral Squamous Cell Carcinoma.

Oral squamous cell carcinoma (OSCC) occasionally occurs in young patients and is likely to be distinct from OSCC in older patients. In this retrospective study, we described the clinicopathologic features and outcome of 150 OSCCs that were diagnosed in patients 40-year-old or younger. Most patients (63%) were non-smokers. The most common site of the primary tumor was oral tongue (n = 131, 87%), followed by gingiva (n = 9), buccal mucosa (n = 8) and lip (n = 2). The median patients' age at presentation was 34 (range: 16-40). Seven patients (5%) had Fanconi anemia with the gingiva being the most common location (4/7, 57%). All OSCCs were of keratinizing type. All cases tested for high-risk HPV (n = 34) were negative. On univariate analysis, high tumor budding was associated with decreased overall survival (OS) and distant metastasis free survival (DMFS), pattern of invasion correlated with OS and tumors with high stromal tumor infiltrating lymphocytes (sTIL) were associated with improved locoregional recurrence free survival (LRFS). Compared with patients 31 to 40-year-old, OSCC in the younger group was associated with significant less alcohol consumption (p = 0.011) and decreased DSS (p = 0.003) and DMFS (p = 0.023). On multivariate analysis, younger age (30 years or younger) was an independent prognostic factor for worse OS and DSS, whereas histologic grade was an independent prognostic factor for DSS. In summary, most OSCC in young patients occurred in non-smokers and did not occur in association with Fanconi anemia. Independent prognostic factors included age at presentation (30 years or younger) for OS and DSS, and histologic grade for DSS.

Immunochemistry in the work-up of mesothelioma and its differential diagnosis and mimickers.

The differential diagnosis in cellular effusions with cytological atypia often includes malignant mesothelioma (MM), reactive mesothelial proliferation, and malignancies of metastatic origin, particularly carcinomas. The International Reporting System for Serous Fluid recently established guidelines for reporting MM. In conjunction with the cytomorphologic evaluation, the role of immunochemistry (IC) was emphasized as a very useful tool in the workup of serous fluids, especially with the availability of novel markers. Utilizing a panel of markers, IC allows the characterization of the cells, whether mesothelial or not, and when mesothelial origin is established, IC can frequently assist in delineating its benign or malignant nature. IC can also confirm metastatic disease, allowing the identification of the primary origin in most cases. This review summarizes the current status of IC and its role in the diagnosis of MM and its differential diagnosis in serous fluids.

A Comparative Study of 22G versus 19G Needles for EUS-Guided Biopsies for Parenchymal Liver Disease: Are Thinner Needles Better?

BACKGROUND AND AIMS: Data on comparative efficacy of various available endoscopic ultrasound-guided liver biopsy (EUS-LB) needles are limited. We sought to compare the performance of a novel Franseen-tip 22G fine-needle biopsy (FNB) device to that of 19G needle platforms for liver parenchyma. METHODS: Consecutive patients referred for EUS and suspected to have hepatic parenchymal disease underwent EUS-LB using different EUS needles and were included in this retrospective study. Two blinded expert liver pathologists independently reviewed and reported on: total number of tissue fragments, length of longest fragment, number of complete and incomplete portal tracts (CPT and IPT), and specimen adequacy. RESULTS: A 22G Franseen-tip needle (A) was used in 30 patients; 19G Tru-Cut needle (B) in 50 patients; 19G reverse beveled non-Tru-Cut needle (C) in 27 patients; and a 19G flexible non-Tru-Cut needle (D) in 28 patients. In the order of needles, A, B, C and D, > 10 tissue fragments were obtained in 100%, 6%, 82%, and 96% samples, the mean number of CPTs was 6.9; 3.0; 7.3; and 16.9, length of longest fragment was 3.8, 4. 7, 3.9, and 8.4 mm, and specimen adequacy was 66.7%, 46%, 82.1%, and 81.5%, respectively. A positive correlation was obtained between number of CPTs and length of longest fragment in samples accrued by 19G needles. CONCLUSION: EUS-LB specimens using 22G Franseen-tip needle appear highly fragmented, leading to inferior specimen adequacy compared to 19G non-Tru-Cut needles. We also report on using length of longest fragment as an additional criterion for specimen adequacy as it positively correlates with number of CPTs standard.

Malignant Peritoneal Mesothelioma Arising in Young Adults With Long-standing Indwelling Intra-abdominal Shunt Catheters.

Only 50% to 70% of patients with mesothelioma report asbestos exposure. Other exposures (eg, radiation) play a role in some cases, but some patients have no obvious cause. We describe a series of patients with long-standing indwelling intra-abdominal shunt catheters who developed malignant peritoneal mesothelioma, suggesting a novel association. We identified 7 patients who had shunts and subsequently developed mesothelioma (5 women; median age: 31 y, range: 18 to 45 y). Clinical history and pathology materials were reviewed, and RNA sequencing was performed. Clinical presentations varied; 6 patients had hydrocephalus and a ventriculoperitoneal shunt, and 1 patient had portal hypertension and a portoatrial shunt. The median duration of shunt therapy in 5 cases was 29 years (range: 12 to 35 y); the remaining 2 patients also had shunts for many years, but specific details were unavailable. Two patients had radiotherapy for malignancies in childhood. One had an alleged exposure to asbestos and 1 had prior exposure to talc. The rest had no known risk factors. Histologically, all tumors were purely epithelioid. Treatments included surgical debulking, chemotherapy, and palliative care. All 7 died of disease (median survival: 7 mo, range: 1 to 18 mo). Molecular testing showed loss of NF2 and CDKN2A/B and a BAP1 mutation in 1 case, and no genomic alterations associated with mesothelioma in 2 cases. Peritoneal mesothelioma may represent a complication of long-standing indwelling shunt catheters. The mechanism is unknown, but chronic peritoneal irritation may play a role. Albeit rare, mesothelioma should be considered in patients with a shunt who present with new ascites.

Usefulness of Restaging Pelvis Magnetic Resonance Imaging After Neoadjuvant Concurrent Chemoradiotherapy in Patients With Locally Advanced Rectal Cancer.

INTRODUCTION: In patients with locally advanced rectal cancer, restaging pelvis magnetic resonance imaging (MRI) after neoadjuvant concurrent chemoradiotherapy is recommended despite its limited accuracy in predicting pathologic T (ypT) and N (ypN) stage. Neoadjuvant rectal (NAR) score is a novel short-term surrogate endpoint for disease-free survival (DFS) and overall survival (OS). We tested the agreement between restaging MRI T (yT) and N (yN) with ypT and ypN stages, respectively, and explored the prognostic significance of restaging MRI NAR (mNAR) score. PATIENTS AND METHODS: Between 2014 and 2018, 43 patients with locally advanced rectal cancer completed neoadjuvant concurrent chemoradiotherapy, had a restaging MRI, and underwent surgery. Weighted kappa was used to test the agreement between yT and yN with ypT and ypN, respectively. A kappa value of less than 0.5 was deemed unacceptable. Paired t test was used to compare NAR and mNAR mean scores. Survival was estimated by Kaplan-Meier curves. RESULTS: Restaging MRI could not predict ypT stage (slight agreement, κ = 0.111) or ypN stage (fair agreement, κ = 0.278). The mean mNAR score was higher than the mean NAR score (20 vs. 16, P = .0079). The median DFS for patients with low-intermediate NAR and high NAR was not reached vs. 30 months (P = .0063). The median OS for patients with low-intermediate NAR and high NAR was not reached vs. 40 months (P = .0056). There was a trend for longer DFS and OS in patients with low-intermediate mNAR scores (not reached in both groups, P = .058) compared to patients with high mNAR scores (not reached in both groups, P = .15). CONCLUSION: Restaging MRI could not predict ypT and ypN stage. The mean mNAR score was higher than the mean NAR score. There was a trend for longer DFS and OS in patients with low-intermediate mNAR scores compared to patients with high mNAR scores.

Misinterpreted Myoepithelial Carcinoma of Salivary Gland: A Challenging and Potentially Significant Pitfall.

Myoepithelial carcinoma (MECA) is an underrecognized challenging entity with a broad morphologic spectrum. Misinterpreting MECA is not uncommon as distinguishing it from its mimics, especially cellular myoepithelial-rich pleomorphic adenoma (PA), can be difficult. We described 21 histologically challenging cases of MECAs (16 MECA ex-PA and 5 MECA de novo). All MECAs ex-PA were intracapsular or minimally invasive except for 3 cases. Eighteen (86%) were initially misinterpreted as benign neoplasms, including PA (10), atypical PA (5), and myoepithelioma (3). The remaining 3 were initially diagnosed as malignant (MECA ex-PA) but were histologically challenging. Histologic features that were found most helpful in recognizing the malignant nature of MECA included: uniformly cellular myoepithelial proliferation with an expansile nodular lobulated pattern (all cases) and alternate hypocellular and hypercellular zonal distribution (76% of cases). Among the 16 MECA patients with follow-up, 14 (87.5%) progressed: 10 developed local recurrence and 5 distant metastases. In contrast, only one of 33 patients with cellular PA (control group) recurred locally. Ten of the 14 MECAs that progressed were MECA ex-PA, and 12 (85%) had an initial benign diagnosis. Two patients with MECA ex-PA died of their disease; one had an initial diagnosis of PA. MECA is a histologically challenging entity that closely mimics PA and seems to carry a significant risk of recurrence. Areas of clonal appearing cellular myoepithelial growth with an expansile nodular lobulated pattern and zonal cellular distribution distinguish the majority of MECAs and may serve as useful diagnostic histologic features to differentiate MECA from its benign mimics.

Malignant Peritoneal Mesothelioma in the setting of a Ventriculo-Peritoneal Shunt: A novel clinical presentation.

We report a case of malignant peritoneal mesothelioma (MPM) in a 31-year-old male with history of cerebral palsy, hydrocephalus, and ventriculoperitoneal shunt (VPS) placed since infancy. He presented with fever, abdominal pain and distension. Computed tomography scan revealed a thick-walled rim-enhancing fluid collection, interpreted as pseudocyst. Intraoperatively, diffuse nodular peritoneal thickening with adhesions was demonstrated. The resection specimen consisted of multiple membranous fragments displaying firm nodules. Microscopic examination revealed a tumefactive malignant-appearing epithelioid proliferation involving the peritoneum, focally invading the underlying fat. Immunohistochemically, the tumor cells expressed keratin AE1/AE3, CK7, CK5/6, Calretinin, WT1 and D2-40, and were negative for CEA and MOC31. The findings were consistent with MPM, epithelioid type. The patient's condition continued to decline with increasing abdominal distension during the month following the original diagnosis. While atypical mesothelial hyperplasia has been described in association with long standing VPS, well-documented cases of MPM have not been previously reported in such context.

Comparison of Risk Stratification Models to Predict Recurrence and Survival in Pleuropulmonary Solitary Fibrous Tumor.

INTRODUCTION: Solitary fibrous tumors (SFTs) are rare mesenchymal neoplasms. Most follow a benign course, but a subset will recur or metastasize. Various risk stratification schemes have been proposed for SFTs, but none has been universally endorsed and few have focused on pleuropulmonary SFTs. METHODS: Histologic sections from surgically resected pleuropulmonary SFTs were examined, with confirmatory immunohistochemistry. Patients were risk-stratified by using four prediction models as proposed by de Perrot, Demicco (original and modified), and Tapias. Kaplan-Meier analysis was used to estimate overall survival (OS) and progression-free survival (PFS). RESULTS: The 147 study patients included 78 females (53.1%) with a median age of 61.5 years (range 25-87). The median follow-up was 5.5 years (range 0-33). Recurrence or metastasis occurred in 15 patients (10.2%), with five deaths from disease. Significant predictors of worse OS included male sex, age at least 55 years, tumor size at least 10 cm, nonpedunculated growth, severe atypia, necrosis, and mitotic count of at least four per 10 high-power fields. Predictors of recurrence included tumor size of at least 10 cm, severe atypia, necrosis, at least four mitoses per 10 high-power fields, and Ki67 labeling index of at least 2%. All systems predicted PFS, but only the Demicco and Tapias systems significantly predicted OS. The modified Demicco system provided the best discrimination for PFS (C-statistic = 0.80 compared with 0.78). CONCLUSION: The risk scoring systems proposed by Tapias et al. and Demicco et al. were both predictive of OS and PFS. The Demicco system has the advantages of simplicity and applicability to SFTs from other sites, as well as provision of the best discrimination for PFS, and thus may be the best system to apply in general practice.

Is ALK-gene rearrangement overlooked in primary gastrointestinal T-cell lymphomas? About two cases.

A 41-year-old male patient with a history of ankylosing spondylitis and Crohn disease, treated with immunomodulators and disease-modifying drugs, was diagnosed with a primary intestinal T-cell lymphoma that followed a 7.5-year-course. This transmural proliferation lacked cytological characteristics of anaplastic large cell lymphoma (ALCL), and was CD8-positive, and CD30- and anaplastic lymphoma kinase (ALK)-negative by immunohistochemistry (IHC). However, ALK-gene rearrangement (ALK-gr) was detected by fluorescence in situ hybridization (FISH) in both initial and persistent disease. The possibility of indolent T-cell lymphoproliferative disease of the gastrointestinal tract with atypical features (transmural involvement) related to ALK-gr was suggested. A previous case of aggressive 'enteropathy-associated ALCL' in the context of celiac disease was recently reported, which also lacked anaplastic morphology, and where CD30 and ALK expression was incidentally demonstrated by IHC, and ALK-gr subsequently confirmed by FISH. These two recent cases represent two distinct rare entities pertaining to the group of primary intestinal T-cell lymphomas, and they both show unexpected ALK-gr. This suggests that ALK-gr has been overlooked in the group of primary intestinal T-cell lymphomas. Performing IHC and FISH tests for ALK-gr in primary gastrointestinal T-cell lymphomas might be of importance, particularly with the advancement of targeted therapy that could impact treatment and prognosis.

Micronodular thymic neoplasms: case series and literature review with emphasis on the spectrum of differentiation.

We report nine cases of micronodular thymoma with lymphoid B-cell hyperplasia and one case of micronodular thymic carcinoma with lymphoid hyperplasia from our institution. For a better understanding of these rare tumors, clinical records, and histological features of these cases were reviewed, with detailed review of additional 64 literature cases of micronodular thymic neoplasms. The joint analysis identified 64 cases of micronodular thymoma with lymphoid B-cell hyperplasia and 9 cases of micronodular thymic carcinoma with lymphoid hyperplasia. Both groups revealed slight male predilection, with male:female ratio of 1.3:1 and 5:4, and occurred at >40 years of age, with a mean of 64 (41-83) and 62 (42-78) years, respectively. Myasthenia gravis was noted in 3/64 (5%) and 1/9 (11%) patients, respectively. Other systemic, disimmune, or hematologic disorders were noted in 6/64 (9%) and 1/9 (11%) patients, respectively. Components of conventional thymoma were reported in 11/64 (17%) micronodular thymomas with lymphoid B-cell hyperplasia, with transitional morphology between the two components in most of them. Cellular morphology was predominantly spindle in micronodular thymoma with lymphoid B-cell hyperplasia when specified (30/43), and epithelioid in micronodular thymic carcinoma with lymphoid hyperplasia (6/9), and cytological atypia was more encountered in the latter. Dedifferentiation/transformation from micronodular thymoma with lymphoid B-cell hyperplasia to micronodular thymic carcinoma with lymphoid hyperplasia seems to occur in a small subset of cases. Three cases of micronodular thymomas with lymphoid B-cell hyperplasia were described with co-existent low-grade B-cell lymphomas. Follow-up data were available for 30 micronodular thymomas with lymphoid B-cell hyperplasia and 6 micronodular thymic carcinomas with lymphoid hyperplasia, with a mean of 47 (0.2-180) months and 23 (3-39) months, respectively. Patients were alive without disease, except for five micronodular thymoma with lymphoid B-cell hyperplasia patients (dead from unrelated causes), and one micronodular thymic carcinoma with lymphoid hyperplasia patient (dead of disease).

One hundred thirteen consecutive transgastric liver biopsies for hepatic parenchymal diseases: a single-institution study.

The transgastric approach is a novel method for obtaining liver biopsies in patients undergoing upper gastrointestinal endosonography. Avoidance of vascular puncture and ability to acquire tissue in patients with obesity or ascites offers a practice niche for this technique. Although several series have reported on specimen adequacy, biopsy core length, and number of portal tracts, none has addressed the diagnostic challenges presented by the fragmented nature of these specimens. We systematically evaluated 113 transgastric liver biopsies obtained for diagnosis of parenchymal liver disease by 3 needle types and compared them with 100 percutaneous and 100 transjugular liver biopsies, respectively. Parameters recorded were number of tissue cores, sizes of longest and shortest cores, numbers of complete and incomplete portal tracts, morphologic characteristics, and adequacy of specimen for diagnosis and staging. In contrast to percutaneous and transjugular liver biopsies, transgastric biopsies often contained >10 tissue fragments and smaller tissue cores. In addition, 2 of the 3 types of transgastric needles obtained less numbers of complete portal tracts. Transjugular biopsies were also smaller and contained less number of complete portal tracts than percutaneous specimens but, unlike transgastric biopsies, only rarely contained >10 tissue fragments. Specimen adequacy for diagnosis and staging was 80%, 100%, and 98% for transgastric, percutaneous, and transjugular biopsies, respectively. Difference in specimen adequacy is related to tissue fragmentation of transgastric liver biopsies rather than biopsy core length or numbers of complete portal tracts. Tissue fragmentation is particularly challenging for staging chronic liver disease.

Torsion of the gonad in the pediatric population: spectrum of histologic findings with focus on aspects specific to neonates and infants.

Histopathologic findings of gonadal torsion in neonates and infants (GTNI) are poorly defined in the literature. We describe herein the histopathologic spectrum of GT with emphasis on the pediatric population and on features specific for NI (≤1 year of age). Twenty-four cases of GTNI (6 females/18 males), 33 cases of GT in an older pediatric population (OPP) (19 females/14 males), and 43 cases of GT in adults (35 females/8 males) were found in our pathology files between 2003 and 2011. Our findings disclosed 2 categories of GT: 1) the group of NI, and 2) that of OPP and adults who share a similar presentation as acute hemorrhagic necrosis of the gonad. Although findings in NI were rather uniform, a few differences were demonstrated between the 2 genders. All GTNI revealed calcifications, fibrosis, siderophages, and extensive necrosis. However, prominent necrotizing palisaded granulomatas were seen in most (4 of 6) cases of ovarian torsion but not in the testicular counterpart. Furthermore, complete gonad regression was encountered exclusively in neonatal testicular torsion cases. In conclusion, 1) pathologic findings in GT are distinctly different between NI and OPP, the latter being more comparable to adults, presenting with acute hemorrhagic necrosis; 2) the distinctive findings in GTNI of both genders include calcifications, siderophages, and fibrosis, in addition to background necrosis; 3) of particular note, complete gonadal regression is seen only in the testis in GTNI; and 4) necrotizing palisaded granulomatas are unique to the ovarian subgroup and are often extensive, obscuring the nature of the process.

Primary dural lymphoma: a novel concept of heterogeneous disease.

Spinal primary dural lymphoma (PDL) is uncommon with a total of 37 previous well-documented cases reported, including one diagnosed in the authors' institution. More recently we encountered an additional case of spinal PDL that, similarly to our previous case, was grade 1-2 follicular B-cell PDL. Our two cases were diagnosed over a 3-year interval in a 72-year-old female and a 74-year-old male, respectively. An exhaustive literature review on PDL was performed consequently to reveal that: (i) spinal and cerebral sites of involvement by PDL are constantly mutually exclusive; and (ii) unlike cerebral PDL, which is usually of marginal zone B-cell type, only two of the 38 cases of spinal PDL were diagnosed as such, diffuse large B-cell lymphoma being the most commonly encountered type in the spine. This divergence infers that, in contrast to the prevailing concept that PDL is a unique disease group, PDL appears to be rather heterogeneous with a difference in predilection of lymphoma type for the anatomical site of dural involvement. Such a site-specific lymphoma-type predilection phenomenon, well-recognized in other organ systems, has not been acknowledged in PDL. This report brings new insights into PDL, and may contribute to a better understanding of nervous system pathophysiology and lymphoma classification.

Micropapillary carcinoma: new variant of prostatic acinar adenocarcinoma.

A micropapillary variant of prostatic acinar adenocarcinoma has not been reported in the literature. Herein, we report a case of a 50-year-old patient who presented with an elevated prostate-specific antigen concentration and was subsequently diagnosed with prostatic acinar adenocarcinoma on biopsy. Radical prostatectomy specimen revealed prostatic carcinoma with Gleason score 4 + 5  =  9/10, with micropapillary component constituting 80% of tumor volume. Immunohistochemical studies of the prostate carcinoma showed a homogeneously positive prostate-specific antigen and α-methylacyl-CoA racemase, high-molecular-weight cytokeratin, and p63 protein cocktail pattern of staining in both micropapillary and conventional components. Pelvic lymph nodes were negative for metastatic disease. In contrast to the aggressive behavior of micropapillary carcinomas of other organs, the disease in our patient has thus far followed a more benign course, with low stage on presentation and a 2-year follow-up free of disease. However, prognostic correlation should be established on large series in order to assign this variant to a grade category within the Gleason scheme.