Postexercise reflex facilitation in Lambert-Eaton myasthenic syndrome.

A 62-year-old woman had 6 months of proximal weakness, fatigue and occasional diplopia, symptoms normally suggesting myasthenia gravis or inflammatory myopathy. Postexercise reflex facilitation is a bedside clinical sign that points to a diagnosis of the rarer alternative, Lambert-Eaton myasthenic syndrome (LEMS). We confirmed this diagnosis using electrodiagnostic short exercise testing and serum assay for voltage-gated calcium channel antibodies. Further investigation identified a small cell neuroendocrine carcinoma of the gallbladder, not previously associated with LEMS. Postexercise reflex facilitation is an important bedside clinical finding that helps clinicians to distinguish LEMS from its mimics.

Tissue-Specific microRNA Expression Profiling to Derive Novel Biomarkers for the Diagnosis and Subtyping of Small B-Cell Lymphomas.

Accurate diagnosis of the most common histological subtypes of small B-cell lymphomas is challenging due to overlapping morphological features and limitations of ancillary testing, which involves a large number of immunostains and molecular investigations. In addition, a common diagnostic challenge is to distinguish reactive lymphoid hyperplasia that do not require additional stains from such lymphomas that need ancillary investigations. We investigated if tissue-specific microRNA (miRNA) expression may provide potential biomarkers to improve the pathology diagnostic workflow. This study seeks to distinguish reactive lymphoid proliferation (RL) from small B-cell lymphomas, and to further distinguish the four main subtypes of small B-cell lymphomas. Two datasets were included: a discovery cohort (n = 100) to screen for differentially expressed miRNAs and a validation cohort (n = 282) to develop classification models. The models were evaluated for accuracy in subtype prediction. MiRNA gene set enrichment was also performed to identify differentially regulated pathways. 306 miRNAs were detected and quantified, resulting in 90-miRNA classification models from which smaller panels of miRNAs biomarkers with good accuracy were derived. Bioinformatic analysis revealed the upregulation of known and other potentially relevant signaling pathways in such lymphomas. In conclusion, this study suggests that miRNA expression profiling may serve as a promising tool to aid the diagnosis of common lymphoid lesions.

Immune pathway upregulation and lower genomic instability distinguish EBV-positive nodal T/NK-cell lymphoma from ENKTL and PTCL-NOS.

Primary Epstein-Barr virus (EBV)-positive nodal T/NK-cell lymphoma (PTCL-EBV) is a poorly understood disease which shows features resembling extranodal NK/T-cell lymphoma (ENKTL) and is currently not recognized as a distinct entity but categorized as a variant of primary T-cell lymphoma not otherwise specified (PTCL-NOS). Herein, we analyzed copynumber aberrations (n=77) with a focus on global measures of genomic instability and homologous recombination deficiency and performed gene expression (n=84) and EBV miRNA expression (n=24) profiling as well as targeted mutational analysis (n=16) to further characterize PTCL-EBV in relation to ENKTL and PTCL-NOS. Multivariate analysis revealed that patients with PTCL-EBV had a significantly worse outcome compared to patients with PTCL-NOS (P=0.002) but not to those with ENKTL. Remarkably, PTCL-EBV exhibited significantly lower genomic instability and homologous recombination deficiency scores compared to ENKTL and PTCL-NOS. Gene set enrichment analysis revealed that many immune-related pathways, interferon α/γ response, and IL6_JAK_STAT3 signaling were significantly upregulated in PTCLEBV and correlated with lower genomic instability scores. We also identified that NFκB-associated genes, BIRC3, NFKB1 (P50) and CD27, and their proteins are upregulated in PTCL-EBV. Most PTCL-EBV demonstrated a type 2 EBV latency pattern and, strikingly, exhibited downregulated expression of most EBV miRNA compared to ENKTL and their target genes were also enriched in immune-related pathways. PTCL-EBV also showed frequent mutations of TET2, PIK3CD and STAT3, and are characterized by microsatellite stability. Overall, poor outcome, low genomic instability, upregulation of immune pathways and downregulation of EBV miRNA are distinctive features of PTCL-EBV. Our data support the concept that PTCL-EBV could be considered as a distinct entity, provide novel insights into the pathogenesis of the disease and offer potential new therapeutic targets for this tumor.

T-Cell Lymphoma Clonality by Copy Number Variation Analysis of T-Cell Receptor Genes.

T-cell lymphomas arise from a single neoplastic clone and exhibit identical patterns of deletions in T-cell receptor (TCR) genes. Whole genome sequencing (WGS) data represent a treasure trove of information for the development of novel clinical applications. However, the use of WGS to identify clonal T-cell proliferations has not been systematically studied. In this study, based on WGS data, we identified monoclonal rearrangements (MRs) of T-cell receptors (TCR) genes using a novel segmentation algorithm and copy number computation. We evaluated the feasibility of this technique as a marker of T-cell clonality using T-cell lymphomas (TCL, n = 44) and extranodal NK/T-cell lymphomas (ENKTLs, n = 20), and identified 98% of TCLs with one or more TCR gene MRs, against 91% detected using PCR. TCR MRs were absent in all ENKTLs and NK cell lines. Sensitivity-wise, this platform is sufficiently competent, with MRs detected in the majority of samples with tumor content under 25% and it can also distinguish monoallelic from biallelic MRs. Understanding the copy number landscape of TCR using WGS data may engender new diagnostic applications in hematolymphoid pathology, which can be readily adapted to the analysis of B-cell receptor loci for B-cell clonality determination.

Laryngeal gout mimicking chondrosarcoma with concurrent longus colli tendinitis.

A 42-year-old man with multiple comorbidities, including gout, presented to the emergency department with severe odynophagia for 4 days with intermittent dysphagia for 1-2 months. A CT scan of the neck showed right longus colli tendinitis and partially calcified excrescences from the right thyroid cartilage which raised suspicion of a cartilaginous tumour. He underwent an MRI scan of the neck to better evaluate the thyroid cartilage findings, which showed a heterogeneous mass suspicious for a chondroid tumour. He then underwent a positron-emission tomography-CT scan which showed a fluorodeoxyglucose-avid mass containing foci of calcification involving the right thyroid cartilage and adjacent strap muscle, with high standardised uptake value of 7.7. He subsequently underwent a CT-guided biopsy and an open biopsy of the right thyroid cartilage, and the results revealed gouty tophi. To our knowledge, this is the first reported case of laryngeal gout with longus coli tendinitis, both of which are rare conditions.

A rare case of bipartite combined tumour of the oesophagus.

BACKGROUND: Bipartite combined oesophageal tumours are an exceedingly rare entity and much less is known about the natural history of these tumours following curative surgery. The authors present a case of a bipartite combined oesophageal tumour comprising of sarcomatoid carcinoma and small cell carcinoma with early postoperative recurrence. CASE PRESENTATION: A 63-year-old Chinese male with a smoking history presents with hemoptysis on a background of dysphagia and odynophagia for 1 month. An endoscopic evaluation found an exophytic oesophageal tumour with contact bleeding for which biopsy of this lesion returned as a malignant high-grade tumour where immunohistochemistry staining was unable to establish the lineage of the tumour. Differential diagnoses include sarcomatoid carcinoma and malignant undifferentiated sarcoma. With the provisional diagnosis of a high-grade oesopheageal sarcoma, the patient underwent minimally invasive McKeown's oesophagectomy. Final histological assessment was pT1bN0 with two histological types of malignancy within a single tumour-70% poorly differentiated spindle cell squamous carcinoma and small cell carcinoma. He was planned for adjuvant chemotherapy in view of the small cell carcinoma component after the resolution of the postoperative infective collections. A computed tomographic scan performed 4 months postoperatively demonstrated metastasis to the lung, pleura, thoracic nodes and liver. Biopsy of the largest lung nodule confirmed small cell neuroendocrine carcinoma with features similar to the small cell carcinoma component in the prior oesophagectomy specimen. He was thereafter initiated on palliative chemotherapy aimed at three weekly carboplatin and etoposide aimed at a total of 4 cycles with peglasta support. Etoposide was stopped during the first cycle due to asymptomatic bradycardia. The regime was then converted to carboplatin with irinotecan for 5 cycles. Repeat computed tomographic scan performed 3 weeks after the completion of chemotherapy showed a complete response of lung and liver metastasis and no evidence of local recurrence or distant metastasis. CONCLUSION: The management of bipartite combined oesophageal tumours should be guided by its more aggressive component. Bipartite combined oesophageal tumours with a small cell carcinoma component are believed to demonstrate aggressive tumour biology likened to that of primary oesophageal small cell carcinoma. Preoperative confirmation of a combined tumour may be challenging, and biopsy results may only yield one of the two components. The more aggressive component is usually a small cell carcinoma, for which the mainstay of therapy is platinum-based chemotherapy rather than surgery.

Giant phaeochromocytoma presenting with an acute stroke: reappraising phaeochromocytoma surveillance for the neurofibromatosis type 1 phakomatosis.

Neurofibromatosis type 1 (NF1) is a multisystem genetic disorder associated with reduced lifespan attributed largely to malignancy and vascular causes. One of the tumours associated with NF1 is phaeochromocytoma. The phaeochromocytoma has earned the moniker, a 'great mimicker', due to its varied means of presentation. We present a patient with NF1 who was diagnosed with a giant 20 cm phaeochromocytoma after suffering from an ischaemic stroke. Current guidelines do not advocate surveillance of phaeochromocytoma in asymptomatic patients with NF1, unlike other genetic syndromes associated with phaeochromocytoma. However, there is increasing evidence that this approach may not help in the early detection and treatment of this potentially life-threatening disease. Our patient remained hypertensive after surgery despite achieving biochemical cure. The suggested chronicity of the underlying tumour in our patient is a reminder to practising clinicians to rethink our strategy in identifying phaeochromocytoma in adults with NF1.

Solitary fibrous tumor of the adrenal gland with unusual immunophenotype: a potential diagnostic problem and a brief review of endocrine organ solitary fibrous tumor.

Solitary fibrous tumor was initially thought to be a pleura-based tumor. However, over the last two decades, its involvement in a variety of extrapleural sites gained recognition. Nonetheless, a primary involvement of the endocrine organs is rare, and in this report, we detail an instance where the tumor affected the adrenal gland of a 71-year-old Arab man. On histology, besides the typical morphologic features seen in solitary fibrous tumor, the neoplasm also exhibited unusual features on immunohistochemistry such as positive staining for cytokeratin AE1/3 and calponin in conjunction with diffuse expression for S-100. The genetic tests for t(X:18) as seen in synovial sarcoma were negative, and the overall histological appearance favored a diagnosis of solitary fibrous tumor. To the best of our knowledge, this report represents the fifth case of a solitary fibrous tumor primarily occurring in the adrenal gland. The differential diagnoses of this neoplasm in our case and a brief summary of solitary fibrous tumor primarily involving the various endocrine organs are presented.

Intensely hypermetabolic extra-axial brainstem tumor in Erdheim-Chester disease.

Erdheim-Chester disease is a rare non-Langerhans cell histiocytosis characterized by progressive histiocytic proliferation with multiorgan involvement, typically of the kidney, skin, brain, and lung, and less frequently, the heart and retro-orbital tissue. Fluorine-18 fluorodeoxyglucose positron emission tomography (F-18 FDG PET) plays an important role in the management of this disease. It has been reported that FDG PET imaging allows accurate evaluation of the extent of the disease at baseline, as well as assessment of response to any specific therapy. In this case, a 57-year-old Chinese man presented with functional decline and a urinary tract infection. He had a prior history of xanthogranulomas of bilateral canthal masses. On imaging, he was found to have left hydronephrosis, diffuse urothelial thickening, increased density of the perinephric fat, mural thickening of the descending aorta and soft tissue masses along the posterior wall of the right atrium extending into the region of the interatrial septum and involving the right atrioventricular groove. Histopathology revealed retroperitoneal fibrosis. An IV contrast-enhanced FDG PET scan showed increased activity in a previously unidentified brain stem mass and the shafts of bilateral femora. Varying levels of FDG uptake were seen in the other lesions.