Molecular alterations associated with metastases of solid pseudopapillary neoplasms of the pancreas.

Solid pseudopapillary neoplasms (SPN) of the pancreas are rare, low-grade malignant neoplasms that metastasise to the liver or peritoneum in 10-15% of cases. They almost invariably present somatic activating mutations of CTNNB1. No comprehensive molecular characterisation of metastatic disease has been conducted to date. We performed whole-exome sequencing and copy-number variation (CNV) analysis of 10 primary SPN and comparative sequencing of five matched primary/metastatic tumour specimens by high-coverage targeted sequencing of 409 genes. In addition to CTNNB1-activating mutations, we found inactivating mutations of epigenetic regulators (KDM6A, TET1, BAP1) associated with metastatic disease. Most of these alterations were shared between primary and metastatic lesions, suggesting that they occurred before dissemination. Differently from mutations, the majority of CNVs were not shared among lesions from the same patients and affected genes involved in metabolic and pro-proliferative pathways. Immunostaining of 27 SPNs showed that loss or reduction of KDM6A and BAP1 expression was significantly enriched in metastatic SPNs. Consistent with an increased transcriptional response to hypoxia in pancreatic adenocarcinomas bearing KDM6A inactivation, we showed that mutation or reduced KDM6A expression in SPNs is associated with increased expression of the HIF1α-regulated protein GLUT1 at both primary and metastatic sites. Our results suggest that BAP1 and KDM6A function is a barrier to the development of metastasis in a subset of SPNs, which might open novel avenues for the treatment of this disease. © 2018 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

Case Report: Middle lobe syndrome: a rare presentation in eosinophilic granulomatosis with polyangiitis.

Background: Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a group of disorders characterized by necrotizing inflammation of small- and medium-sized blood vessels and the presence of circulating ANCA. Eosinophilic granulomatosis with polyangiitis (EGPA) is a systemic ANCA-associated vasculitis, characterized by peripheral eosinophilia, neuropathy, palpable purpuras or petechiae, renal and cardiac involvement, sinusitis, asthma, and transient pulmonary infiltrates. Middle lobe syndrome (MLS) is defined as recurrent or chronic atelectasis of the right middle lobe of the lung, and it is a potential complication of asthma. Case presentation: Herein, we describe a case of MLS in a 51-year-old woman, never-smoker, affected by EGPA, presenting exclusively with leukocytosis and elevated concentrations of acute-phase proteins, without any respiratory symptom, cough, or hemoptysis. Chest computed tomography (CT) imaging documented complete atelectasis of the middle lobe, together with complete obstruction of lobar bronchial branch origin. Fiberoptic bronchoscopy (FOB) revealed complete stenosis of the middle lobar bronchus origin, thus confirming the diagnosis of MLS, along with distal left main bronchus stenosis. Bronchoalveolar lavage (BAL) did not detect any infection. Bronchial biopsies included plasma cells, neutrophil infiltrates, only isolated eosinophils, and no granulomas, providing the hypothesis of vasculitic acute involvement less likely. First-line agents directed towards optimizing pulmonary function (mucolytics, bronchodilators, and antibiotic course) were therefore employed. However, the patient did not respond to conservative treatment; hence, endoscopic management of airway obstruction was performed, with chest CT documenting resolution of middle lobe atelectasis. Conclusion: To the best of our knowledge, this is the first detailed description of MLS in EGPA completely resolved through FOB. Identification of MLS in EGPA appears essential as prognosis, longitudinal management, and treatment options may differ from other pulmonary involvement in AAV patients.

Epstein-Barr Virus-Positive Mucocutaneous Ulcer Mimicking Rectal Carcinoma at 18F-FDG PET/CT.

We report focally intense F-FDG PET/CT rectal activity (SUVmax = 25) with a horseshoe distribution in an 81-year-old man with B-cell chronic lymphocytic leukemia and suspected Richter transformation. While imaging findings were typical for rectal adenocarcinoma, histology revealed Epstein-Barr virus-positive mucocutaneous ulcer.

Retroperitoneal Endometriosis: A Possible Cause of False Positive Finding at (18)F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography.

Endometriosis is a frequent and clinically relevant problem in young women. Laparoscopy is still the gold standard for the diagnosis of endometriosis, but frequently both morphologic and functional imaging techniques are involved in the diagnostic course before achieving a conclusive diagnosis. We present a case of a patient affected by infiltrating retroperitoneal endometriosis falsely interpreted as a malignant mass by contrast-enhanced magnetic resonance imaging and (18)F-fluorodeoxyglucose positron emission tomography/computed tomography.

Response criteria for malignant lymphoma.

In the last 35 years, many attempts have been made to define criteria for the assessment of treatment response in malignant lymphoma. These systems, with respect to both morphological and molecular imaging, aim to standardize scan results, in order to simplify the interpretation of findings, facilitate multicentric research trials, and compare published data. Unfortunately, there is no consensus among the main international hematological associations on which criteria are the most appropriate. This detailed and comprehensive description of all classifications intends to focus attention on this topic.

Wagner-Meissner-like corpuscles in gastric mucosa: a brief report.

Wagner-Meissner corpuscles are touch receptors that are located in dermal papillae and are usually absent in gastrointestinal mucosa. Wagner-Meissner-like corpuscles have been reported in association with benign neural neoplasm. A case of Wagner-Meissner-like corpuscles in endoscopically normal gastric mucosa biopsy of a 48-year-old woman is presented here. The corpuscles were positive for S-100 and clinical evidence of neurofibromatosis was negative. From a review of the literature, only 2 cases of tactile corpuscle-like structures in gastric mucosa are available.

Primary peripheral PNET/Ewing's sarcoma of the dura: a clinicopathologic entity distinct from central PNET.

We describe two cases of peripheral primitive neuroectodermal tumor-Ewing's sarcoma (PNET-ES) arising intracranially in the leptomeninges. Both tumors exhibited a primitive undifferentiated round-cell morphology. Immunohistochemical stains revealed strong membrane expression of CD99 in both cases. A t(11;22)(q24;q12) could be demonstrated with reverse transcriptase-polymerase chain reaction in one case, whereas fluorescence in situ hybridization analysis performed in the second case showed a rearrangement of the EWS gene. The occurrence of PNET-ES at this site is very unusual. Immunophenotypical as well as genetic analysis play a key role in the diagnosis and the distinction from central PNET.