Multimodality Imaging Appearance of Intrapericardial Paragangliomas.

Paragangliomas are neuroendocrine tumors of the sympathetic and parasympathetic nervous system that originate from neural crest cells. Less than 1% of paragangliomas are found in the heart, originating from intrinsic cardiac ganglia cells in the posterior wall the atria, atrioventricular groove, and along the root of the great vessels. A 10-year review of our institution's database identified nine patients who had documented intrapericardial paragangliomas. We describe the multimodality imaging appearance of these tumors. The most common findings include embedment and wrapping around the great vessels and atrioventricular groove within the confines of the pericardium, markedly avid heterogeneous enhancement, distinct engorged neovascularization, and in large lesions, central low attenuation areas compatible with hemorrhage, necrosis, or cystic degeneration.

Fine-needle aspiration diagnosis of clonal extramedullary hematopoiesis in a case of myeloproliferative neoplasm.

Extramedullary hematopoiesis (EMH)-the proliferation of hematopoietic progenitors outside of the bone marrow (BM) is a well-known phenomenon in myeloproliferative neoplasms (MPN). Abundant literature describes EMH at various body sites in cases of MPN, and some studies showed the presence of cytogenetic changes associated with MPN in the EMH tissues. We present a case of an 80-year-old female, with a history of MPN, presenting with mediastinal adenopathy. The transbronchial fine-needle aspiration (FNA) of the mediastinal lymph node showed EMH with atypical megakaryocytes and del(13q) demonstrated by fluorescence in situ hybridization. The subsequent BM biopsy demonstrated myelofibrosis with atypical megakaryocytes harboring the same cytogenetic abnormality. Our case highlights the capability of FNA cytology for providing accurate morphologic, immunohistochemical, and cytogenetic diagnosis of clonal EMH.

Pulmonary Lymphangitic Spread of Multiple Myeloma as Early Relapse after Autologous Stem Cell Transplantation.

Clinical relapses early after autologous stem cell transplantation portrays an inferior clinical outcome. Early relapse in this setting with extramedullary disease (EMD) of lung involvement in multiple myeloma is rare. To our knowledge, this is the first reported case of lymphangitic spread of myeloma with pulmonary parenchymal and pleural involvement occurring at first relapse.

Primary pulmonary mucoepidermoid carcinoma: Cyto-histologic correlation and review of the literature.

Preoperative fine needle aspiration diagnosis and cyto-histologic correlation of primary pulmonary mucoepidermoid carcinoma have rarely been described in detail in the literature. A 26-year old male presented at our institution with cough, bloody sputum, and a 4.3 cm left lower lobe lung mass. He was accurately diagnosed with pulmonary mucoepidermoid carcinoma on preoperative aspiration cytology. The patient subsequently proceeded to left lower lobectomy, confirming the diagnosis. In this article, we present a detailed report of primary pulmonary mucoepidermoid carcinoma describing the cytologic and histologic morphologic features, its differential diagnosis with review of the literature.

Activation-induced cytidine deaminase localizes to G-quadruplex motifs at mutation hotspots in lymphoma.

Diffuse large B-cell lymphoma (DLBCL) is a molecularly heterogeneous group of malignancies with frequent genetic abnormalities. G-quadruplex (G4) DNA structures may facilitate this genomic instability through association with activation-induced cytidine deaminase (AID), an antibody diversification enzyme implicated in mutation of oncogenes in B-cell lymphomas. Chromatin immunoprecipitation sequencing analyses in this study revealed that AID hotspots in both activated B cells and lymphoma cells in vitro were highly enriched for G4 elements. A representative set of these targeted sequences was validated for characteristic, stable G4 structure formation including previously unknown G4s in lymphoma-associated genes, CBFA2T3, SPIB, BCL6, HLA-DRB5 and MEF2C, along with the established BCL2 and MYC structures. Frequent genome-wide G4 formation was also detected for the first time in DLBCL patient-derived tissues using BG4, a structure-specific G4 antibody. Tumors with greater staining were more likely to have concurrent BCL2 and MYC oncogene amplification and BCL2 mutations. Ninety-seven percent of the BCL2 mutations occurred within G4 sites that overlapped with AID binding. G4 localization at sites of mutation, and within aggressive DLBCL tumors harboring amplified BCL2 and MYC, supports a role for G4 structures in events that lead to a loss of genomic integrity, a critical step in B-cell lymphomagenesis.

Frequent expression of activation-induced cytidine deaminase in diffuse large B-cell lymphoma tissues from persons living with HIV.

OBJECTIVE: The increased risk for persons living with HIV to develop diffuse large B-cell lymphoma (DLBCL) even in the post-antiretroviral therapy eras suggests a role beyond immunosuppression in lymphoma development. However, the mechanisms leading to lymphoma in the HIV setting are not fully understood. HIV is known to induce activation-induced cytidine deaminase (AID) levels in nonneoplastic B cells in vitro and chronic AID expression may play an important role in lymphomagenesis. Although AID expression is observed in B-cell lymphoma, studies in HIV-associated DLBCL are limited. DESIGN: In this study, we conducted a retrospective review of DLBCL tissues from patients with and without HIV infection to compare expression of AID and B-cell receptors potentially involved in HIV and B-cell interaction. METHODS: We evaluated DLBCL formalin-fixed paraffin-embedded tissues from 72 HIV-seropositive and 58 HIV-seronegative patients for AID, DC-SIGN, and CD40 protein expression. BCL2 and MYC, two well established prognostically significant oncoproteins in DLBCL, were also assessed at the protein and mRNA levels. Subset analysis was performed according to DLBCL subtype and EBV status. RESULTS: Of note, AID expression was more frequent in HIV-associated DLBCL compared with non-HIV-associated DLBCL regardless of cell-of-origin subtype, and also displayed significantly less BCL2 expression. Despite no direct correlation with AID expression, the HIV-DLBCL tissues also exhibited high levels of the DC-SIGN receptor. CONCLUSION: Collectively, these findings support a potential role for AID in the pathogenesis of HIV-associated lymphomas and suggest the need of further investigations into the involvement of the DC-SIGN receptor-signaling pathway.

Hodgkin Lymphoma Mimicking Osteomyelitis.

Hodgkin lymphoma with symptomatic osseous involvement can have a similar presentation to osteomyelitis. Common findings in symptoms, laboratory workup, and imaging can make it very difficult to distinguish between the two diseases. Excisional biopsy should be pursued if fine-needle biopsy is equivocal and suspicion of lymphoma is high. We report a case of a 40-year-old man who presented with a history of marine animal sting on his neck and later developed erythema in the area, chest pain, constitutional symptoms, adenopathy, and imaging classic for sternal osteomyelitis. Fortunately, initial biopsy prompted the possibility of lymphoma, and further workup was initiated, which confirmed Hodgkin lymphoma. This case is a good reminder that malignancies and infections can share many common features, and keeping a broad differential diagnosis can be lifesaving. Proper staging and risk stratification of Hodgkin lymphoma help determine the optimal treatment.