A 23-gene expression signature was recently developed as an adjunct to histopathology to differentiate melanocytic nevi from melanoma. The current study correlated the gene expression signature scores to actual clinical outcomes in cases from the first validation study. RNA was extracted from 127 archival formalin-fixed paraffin-embedded tissue sections of melanocytic lesions. Gene expression was measured using quantitative reverse-transcription polymerase chain reaction, and a weighting algorithm was used to generate a numeric score. Gene expression test results were compared to histopathological diagnoses and development of local recurrence, sentinel lymph node metastases, and distant metastases. Sixty-five lesions were diagnosed histopathologically as melanoma. Fourteen developed metastases. Gene expression test results were malignant in 61 of 65 (93.8%) lesions (including all lesions that metastasized), indeterminate in 2 of 65 (3.1%) lesions, and benign in 2 of 65 (3.1%) lesions. The remaining 62 lesions were diagnosed as benign by histopathology. Gene expression test results were benign in 48 of 62 (77.4%), indeterminate in 7 of 62 (11.3%), and malignant in 7 of 62 (11.3%). There was a strong correlation between the gene expression signature test results and clinical outcomes. All lesions that metastasized were correctly identified by the test as malignant melanoma.

BackgroundAccurate diagnosis of melanoma remains histologically challenging. Dermal mitoses support malignancy, but are only occasionally seen in melanomas. As melanomagenesis is thought to begin at the dermal-epidermal junction, we investigated the significance of epidermal melanocytic mitoses (EMM) in a spectrum of lesions with molecular characterization.MethodsEpidermal mitoses density (EMD) was evaluated in 46 straightforward lesions (24 benign and 22 malignant) and 30 challenging lesions with expert interpretation, fluorescence in situ hybridization and myPath-score characterization (12 favor-benign, 9 favor-malignant and 9 ambiguous). EMD was correlated with clinicopathologic parameters and myPath.ResultsIn straightforward cases, 25% nevi and 77% melanomas had EM. Median EMD was significantly lower in nevi vs. melanomas (0/mm vs. 0.04/mm, p = 0.001). EMD (0.01/mm-cutoff) had 77% sensitivity, 79% specificity discriminating melanomas from nevi. In challenging cases, 17% favor-benign, 67% favor-malignant and 78% ambiguous lesions had EM. EMD (0.01/mm-cutoff) had 67% sensitivity, 82% specificity on 21 non-ambiguous lesions, similar to myPath. EMD was less accurate in Spitzoid lesions, which have high EMD and dermal mitoses.ConclusionWhile EMD is not an adequate single criterion in diagnosing melanoma, our results validate its discriminatory potential, suggesting that EM should prompt closer investigation for malignancy. Expanded studies with clinical follow up are warranted to further assess the EM utility in classifying melanocytic lesions.

Melanoma accounts for most skin cancer-related deaths and has an increasing incidence. Accurate diagnosis and distinction from atypical nevi can be at times difficult using light microscopy alone. Fluorescence in situ hybridization (FISH) and melanoma gene expression score (myPath, Myriad Genetics) have emerged as ancillary tools to further aid in this differential diagnosis. Our aim in this study was to correlate FISH results, gene expression score, consensus histopathologic impression and clinical outcome on a series of 117 challenging melanocytic lesions collected from three separate institutions. The lesions were separated into two groups: 39 histopathologically unequivocal lesions (15 malignant, 24 benign) and 78 challenging lesions interpreted by expert consensus (27 favor malignant, 30 favor benign, and 21 ambiguous). Melanoma-FISH was performed using probes for 6p25, 11q13, 8q24, and 9p21/CEP9 and scored according to established criteria. Analysis by myPath gene expression score was performed and interpreted by the manufacturer as ‘benign', ‘indeterminate,' or ‘malignant'. In the unequivocal group, melanoma-FISH and myPath score showed 97 and 83% agreement with the histopathologic diagnosis, respectively, with 93 and 62% sensitivity, 100 and 95% specificity, and 80% inter-test agreement. In the challenging group, FISH and the myPath score showed 70 and 64% agreement with the histopathologic interpretation, respectively, with 70% inter-test agreement and similar sensitivities and specificities. The inter-test agreement was 73% overall, excluding indeterminate results. Discordant test results occurred in 27/117 cases from both unequivocal and challenging groups. Melanoma-FISH and gene expression score are valuable ancillary tools, though both have limitations and return discordant results in a subset of cases. Follow-up studies with more extensive clinical outcome data are warranted to establish the accuracy of these tests for the classification of melanocytic lesions.

Background: Pathologic complete response (pCR) after neoadjuvant chemotherapy for breast cancer is associated with improved prognosis in aggressive tumor subtypes, including ERBB2-positive tumors. Recent adoption of pCR as a surrogate endpoint for clinical trials in early stage breast cancer in the neoadjuvant setting highlights the need for biomarkers that, alone or in combination, help predict the likelihood of response to treatment.Methods: Biopsy specimens from 29 patients with invasive ductal carcinoma treated with trastuzumab-based therapy prior to definitive resection and pathologic staging were evaluated by dual color bright field in situ hybridization (dual ISH) using probes for MET, TOP2A, PTEN, and PIK3CA genes, each paired with centromeric probes to their respective chromosomes (chromosomes 7, 17, 10, and 3). Ki-67 expression was assessed by immunohistochemistry (IHC). Various parameters describing copy number alterations were evaluated for each gene and centromere probe to identify the optimal parameters for clinical relevance. Combinations of ISH parameters and IHC expression for Ki-67 were also evaluated.Results: Of the four genes and their respective chromosomes evaluated by ISH, two gene copy number parameters provided statistically significant associations with pCR: MET gain or loss relative to chromosome 7 (AUC = 0.791, sensitivity = 92 % and specificity = 67 % at optimal cutoff, p = 0.0032) and gain of PTEN (AUC = 0.674, sensitivity = 38 % and specificity = 100 % at optimal cutoff, p = 0.039). Ki-67 expression was also found to associate significantly with pCR (AUC = 0.726, sensitivity = 100 % and specificity = 42 % at optimal cutoff, p = 0.0098). Combining gain or loss of MET relative to chromosome 7 with Ki-67 expression further improved the association with pCR (AUC = 0.847, sensitivity = 92 % and specificity = 83 % at optimal cutoffs, p = 0.0006).Conclusions: An immunogenotypic signature of low complexity comprising MET relative copy number and Ki-67 expression generated by dual ISH and IHC may help predict pCR in ERBB2-positive breast cancer treated with neoadjuvant chemotherapy and trastuzumab. These findings require validation in additional patient cohorts.

Malignant peripheral nerve sheath tumors are rare soft tissue sarcomas with histological and immunohistochemical similarities to spindle cell melanoma. Although spindle cell melanoma is significantly more common, both tumors may express S100 and lack staining for HMB-45, Melan-A or MITF. Here we present a case of superficial malignant peripheral nerve sheath tumor with diffuse S100 positivity arising in a subtle neurofibroma in close proximity to an intradermal melanocytic nevus. This configuration had led to prior misdiagnosis as a desmoplastic melanoma arising in the nevus and to sentinel lymph node biopsy. Identification of the background neurofibroma, as well as CD34 positivity raised consideration of a low grade malignant peripheral nerve sheath tumor, which was confirmed via observation of Schwannian differentiation on electron microscopy. The importance of distinguishing these two tumors is stressed owing to the difference in management.

Stenotrophomas maltophilia is an opportunistic Gram‐negative bacillus and an important cause of nosocomial infections, particularly in immunosuppressed individuals. Although infections with this organism are most often in the form of pneumonia, bacteremia and endocarditis, awareness of the impact of S. maltophilia skin infections has been increasing. Here we describe a case of S. maltophilia cellulitis in a 65‐year‐old man with severe neutropenia and purpuric skin lesions to highlight the critical histopathological findings and correlate them with the clinical manifestations of the skin infection with this organism. Because identification of S. maltophilia can be challenging and infections are difficult to manage, this case illustrates essential considerations regarding the multifaceted histopathological, dermatological, clinical and microbiological aspects of the diagnosis and treatment of S. maltophilia cellulitis in a severely immunocompromised patient. Cognizance of the increasing incidence of nosocomial infections with uncommon microorganisms such as S. maltophilia is necessary when presented with atypical cutaneous manifestations, particularly in immunocompromised patients.

Introduction:Overexpression of MET receptor tyrosine kinase and its ligand hepatocyte growth factor (HGF) and MET gene amplification have been well-documented in non–small-cell lung cancer (NSCLC). Activated MET signaling plays an important role in human cancer tumorigenesis, metastasis, and drug resistance. However, the deregulation of MET/HGF pathway in NSCLC harboring ALK gene rearrangement (ALK[+]), which is sensitive to dual ALK and MET inhibitor Crizotinib, has not been reported.Methods:We performed systematic analysis of MET/HGF expression by immunohistochemistry (IHC) and MET gene amplification by dual color, dual hapten bright field in situ hybridization in 19 ALK(+) and 73 ALK(−) NSCLC tumor tissues from those who had clinical ALK rearrangement test done at the Cleveland Clinic from August 2010 to January 2013. IHC scoring was interpreted on a standard four-tier system.Results:The percentage of MET IHC score 0, 1+, 2+, and 3+ were 5.5%, 27.8%, 50.0%, and 16.7% in ALK(+) group, compared with 28.8%, 33.9%, 23.7%, and 13.6% in ALK(−) group, respectively. The MET high expression (IHC score 2 or 3) was significantly higher in ALK(+) group statistically (66.7% versus 37.3%, p = 0.03). HGF-high expression (IHC score 2 or 3) was 33.3% in ALK(+) and 15.8% in ALK(−) (p = 0.17). We identified eight cases in ALK(−) and one case in ALK(+) tumor who had MET gene amplification (18.4% versus 7.1%, p = 0.43) by dual color, dual hapten bright field in situ hybridization. No significant correlation between MET protein receptor expression and gene amplification was identified.Conclusions:Our study demonstrated for the first time that MET receptor expression, but not MET gene amplification, is significantly increased in ALK(+) NSCLC. MET gene amplification is a relatively rare event in this unique population compared with ALK(−) NSCLC.

Introduction: Endobronchial ultrasound (EBUS)-guided sampling of the mediastinum has traditionally been performed by fine needle aspiration (FNA) for cytologic evaluation. The ProCore fine needle biopsy, used primarily to obtain intra-abdominal tissue core biopsies, has not been widely used for EBUS. The aim of this study was to evaluate our experience with EBUS-Procore of mediastinal nodes, and to compare its diagnostic utilization to that of conventional EBUS-FNA. Material and Methods: A retrospective review of all EBUS cases of mediastinal masses using a ProCore needle from December 2013 to March 2014 was performed. Patient demographics, anatomic site, number of procedure passes, on-site immediate evaluation, final pathology reports, and ancillary test results were recorded. All specimen slides and cell blocks were evaluated scoring lesion and contamination cellularity (0 Z acellular, 1 Z scant, 2 Z moderate, and 3 Z abundant). Results: There were 18 EBUS cases of mediastinal lymph nodes using Procore in patients (12 female, 6 male) of average age 57 years (range, 3380 years). FNA was followed by Procore biopsy in all cases, except one where only Procore was performed. Cases included benign (granulomas), atypical, and malignant (carcinoma) diagnoses. More FNAs were satisfactory (with 2 unsatisfactory cases) than Procores (with 7 unsatisfactory cases). The 2 non-diagnostic FNA cases remained unsatisfactory with subsequent Procore. More passes were performed with FNA (4/case) than Procore (2.6/case). On average, FNA provided greater cellularity of lesional material (smear score Z 2; cell block score Z 1.4) than Procore (smear score Z 1.4; cell block score Z 1.4). However, FNAs contained more bronchial contamination (smear score Z 1.6; cell block score Z 1) than Procore (smear score Z 1; cell block score Z 0.4). Both sample types contained similar bronchial and blood contamination. Ancillary studies (special stains, immunostains, FISH, molecular) were equally successful using cell blocks from both specimen types. Conclusions: Our preliminary experience shows that EBUS-guided Procore sampling of mediastinal lymph nodes is feasible. Although FNA samples appear to provide more diagnostic cellular material in this pilot series, fewer subsequent Procore passes were required to achieve satisfactory specimens. Procore specimens also contained less obscuring bronchial contamination. Evaluation of more cases and more experience with this new technique is necessary to determine if the diagnostic yield using Procore during EBUS can be improved.

BackgroundDetection of immunoglobulin light-chain restriction is important in the diagnosis of B-cell non-Hodgkin lymphoma (B-NHL). Flow-cytometry, commonly used to evaluate light-chain restriction, is impractical to be used in cutaneous specimens. Immunohistochemical and conventional chromogenic in situ hybridization (CISH) methods on formalin-fixed-paraffin-embedded (FFPE) tissue lack sufficient sensitivity to detect low-level light-chain expression in B-NHL without plasmacytic differentiation. Ultrasensitive bright-field mRNA-ISH (BRISH) for in situ light-chain detection in cutaneous B-NHL has been assessed.DesignKappa/lambda mRNA was detected using two-color BRISH (RNAscope 2xPlex, Advanced Cell Diagnostics) on 27 FFPE skin biopsies and excisions from patients with available B-cell PCR clonality studies: 16 clonal B-cell lesions (6 follicle center lymphoma, 5 marginal zone lymphoma, 3 large B-cell lymphoma, and 2 other) and 11 non-clonal B-cell proliferations.ResultsBRISH was successful in 15/16 clonal B-cell lesions and 11/11 non-clonal proliferations. Light-chain restriction was detected in 15/15 clonal lesions and in 1/11 non-clonal proliferations (96.1% overall concordance with clonality PCR). In 4/5 marginal zone lymphomas, light-chain restriction was detected as strong monotypic mRNA expression in a B-cell subset, consistent with plasmacytic differentiation.ConclusionUltrasensitive BRISH can successfully detect light-chain restriction in B-NHL from FFPE skin specimens and may be a useful adjunct ancillary tool in cases not resolved by CISH or immunohistochemical methods.

Cytogenetic alterations are strong outcome prognosticators in uveal melanoma (UVM). Monosomy 3 (-3) and MYC amplification at 8q24 are commonly tested by fluorescence in situ hybridization (FISH). Alternatively, microarray analysis provides whole genome data, detecting partial chromosome loss, loss of heterozygosity (LOH), or abnormalities unrepresented by FISH probes. Nonfixed frozen tissue is conventionally used for microarray analysis but may not always be available. We assessed the feasibility of genomic microarray analysis for high resolution interrogation of UVM using formalin-fixed paraffin-embedded tissue (FFPET) as an alternative to frozen tissue (FZT). Enucleations from 44 patients (clinical trial NCT00952939) yielded sufficient DNA from FFPET (n = 34) and/or frozen tissue (n = 41) for comparative genomic hybridization and select single nucleotide polymorphism analysis (CGH/SNP) on Roche-NimbleGen OncoChip arrays. CEP3 FISH analysis was performed on matched cytology ThinPrep material. CGH/SNP analysis was successful in 30 of 34 FFPET and 41 of 41 FZT samples. Of 27 paired FFPET/FZT samples, 26 (96.3%) were concordant for at least four of six major recurrent abnormalities (-3, +8q, -1p, +6p, -6q, -8p), and 25 of 27 (92.6%) were concordant for -3. Results of CGH/SNP were concordant with the CEP3 FISH results in 27 of 30 (90%) FFPET and 38 of 41 (92.6%) FZT cases; partial -3q was detected in two CEP3 FISH-negative cases and whole chromosome 3, 4, and 6 SNP-LOH in one case. CGH detection of -3, +8q, -8p on FFPET and FZT showed significant correlation with the clinical outcome measures (metastasis development, time to progression, survival). Results of the UVM genotyping by CGH/SNP on FFPET are highly concordant with those of the FZT analysis and with those of the CEP3 FISH analysis, and therefore CGH/SNP is a practical method for UVM prognostication. Genome-wide coverage provides additional data with potential relevance to UVM biology, diagnosis, and prognosis.

OBJECTIVES:Epidermal growth factor receptor (EGFR) gene mutation status should be determined in all patients with advanced, non-squamous non-small cell lung carcinoma (NSCLC) to guide targeted therapy with EGFR tyrosine kinase inhibitors. EGFR mutations are commonly tested by Sanger sequencing or allele specific polymerase chain reaction (ASPCR) on formalin-fixed paraffin-embedded (FFPE) samples including cell blocks (CB) that may fail due to absence of tumor cells. The cell pellet from cytology specimens obtained at the time of endobronchial guided ultrasound fine needle aspiration (EBUS FNA) (EBUS-TBNA, transbronchial needle aspiration) represents an alternative resource for additional tissue. Here we demonstrate the utility of using the FNA cell pellet versus for the detection of EGFR mutations in NSCLC.MATERIALS AND METHODS:For internal validation, 39 cytology samples from patients with NSCLC referred for EGFR testing were analyzed using the EGFR rotor-gene Q (RGQ) PCR assay (Qiagen). Thereafter, a consecutive series of 228 EBUS FNA samples were tested.RESULTS:The ASPCR assay demonstrated acceptable intra-assay, inter-assay and inter-lot reproducibility, sensitivity, and specificity. For the consecutive series, only 6/228 (2.6%) failed analysis (5 due to insufficient DNA yield). Of 228 EBUS FNA cell pellets tested 32 (14.0%) demonstrated clinically relevant mutations.RESULTS AND CONCLUSION:ASPCR can reliably detect EGFR gene mutations in FNA preparations from patients with NSCLC obtained at EBUS.

INTRODUCTION:Oncogenic anaplastic lymphoma kinase (ALK) gene rearrangements in non-small-cell lung carcinomas (NSCLC) provide the basis for targeted therapy with crizotinib and other specific ALK inhibitors. Treatment eligibility is conventionally determined by the Food and Drug Administration-approved companion diagnostic fluorescence in situ hybridization (FISH) assay on paraffin-embedded tissue (PET). On limited samples such as fine needle aspiration-derived cytoblocks, FISH for ALK is often uninformative. FISH performed on liquid-based ThinPrep slides (ThinPrep-FISH) may represent a robust alternative.METHODS:Two hundred thirty cytology samples from 217 patients with advanced NSCLC, including a consecutive series of 179 specimens, were used to generate matched ThinPrep slides and paraffin cytoblocks. The same ThinPrep slides used for cytologic diagnosis were assessed by standard ALK break-apart two-color probe FISH, after etching of tumor areas. Ultrasensitive ALK immunohistochemistry (IHC) on corresponding cytoblocks [D5F3 antibody, OptiView signal amplification] served as the reference data set.RESULTS:ThinPrep-FISH ALK signals were robust in 228 of 230 cases and not compromised by nuclear truncation inherent in paraffin-embedded tissue-FISH; only two samples displayed no signals. Nine of 178 informative cases (5%) in the consecutive series and 18 of 228 informative cases (7.8%) overall were ALK rearranged by ThinPrep-FISH. In 154 informative matched ThinPrep-FISH and cytoblock-IHC samples, 152 were concordant (10, 6.5% ALK status positive; 142, 92.2% ALK status negative), and two (1.3%) were ThinPrep-FISH positive but IHC negative (sensitivity 100%, specificity 98.6%, overall agreement 98.7%).CONCLUSION:Detection of ALK gene rearrangements in liquid cytology ThinPrep slides derived from patients with NSCLC can be confidently used for clinical ALK molecular testing.

Ample work has been dedicated so far to describing the presentation and the diagnostic features of ocular lymphoma. As is the case with other organs, recognizing benign lymphoid proliferations involving the eye and its adnexal structures is equally important. The spectrum of ocular adnexal lymphoid proliferations (OAL), ranging from benign to malignant, presents with similar and indistinguishable clinico-radiologic features but with very different therapy requirements and clinical outcome. The task to differentiate among the benign lymphoid proliferations, generically termed reactive lymphoid hyperplasia (RLH), and distinguish each from lymphomas, must therefore be accomplished by the pathologist. This process is based upon histologic, immunophenotypic, and molecular analysis.

s presented at the 50th Annual Meeting of the American Society of Dermatopathology October 10–13, 2013 Washington, DC USA Abstracts presented in the 14th Annual Duel in Dermatopathology Resident Competition, Oral Sessions 1, 2 and 3, the Fellows’ Case Presentations and Poster Session are listed on the following pages in the order they were presented.s presented in the 14th Annual Duel in Dermatopathology Resident Competition, Oral Sessions 1, 2 and 3, the Fellows’ Case Presentations and Poster Session are listed on the following pages in the order they were presented.

e22146 Background: 3-5% Non-Small Cell Lung Cancer (NSCLC) harbors ALK gene translocation (ALK(+)) for which targeted ALK inhibitor has greater efficacy and tolerance than cytotoxic chemotherapy. However, resistance to ALK inhibition inevitably occurs and new therapeutic targets are urgently needed in this unique patient population. Interestingly, CD30, a TNF receptor super family member, is commonly expressed in anaplastic large cell lymphoma which is another malignancy associated with ALK gene arrangement in a majority of cases. Targetable CD30 could represent a new therapeutic target in ALK(+) NSCLC. CD30 expression has been observed in a study of 875 multiple types of non-lymphomatous malignancies (3-33%), including one case with small cell lung cancer (4%). The expression of CD30 in NSCLC, especially in ALK(+) NSCLC, is largely unknown. Methods: CD30 expression in the NSCLC cell lines A549, H358, H1666 and H1299 (none containing ALK gene translocation) was tested by western blot, flow cytometry and confocal microscopy using CD30 antibody (Novus biologicals, NBP1 – 72175). We also examined a total of 21 ALK(+) NSCLC and 17 ALK(-) NSCLC patients whose formalin fixed paraffin embedded tumor were available for CD30 immunohistochemistry staining using CD30 antibody (DAKO, M075101, clone Ber-H2) on Ventana Medical Systems Benchmark Ultra Automated Immunostainer (Tucson, AZ). CD30 IHC positive is defined as staining in ≥ 10% tumor cells. Results: CD30 expression was detected at a similar level in all four different NSCLC cell lines by western blot. The CD30 staining in A549 and H1299 was mainly membranous, as demonstrated by confocal microscope and the flow cytometry analysis. We did not detect any CD30 expression by IHC in all 21 ALK(+) and 17 ALK(-) NSCLC tumors. Conclusions: Our in vitro studies showed positive CD30 expression in four different NSCLC cell lines, but no significant CD30 expression was detected by IHC in both ALK(+) and ALK(-) NSCLC tumors. CD30 is unlikely a treatment target in NSCLC with or without ALK gene rearrangement.