State-of-the-Art Imaging and Staging of Plasma Cell Dyscrasias

Avaliação Radiográfica da Maxila e da Mandíbula de Pacientes Diagnosticados com Mieloma Múltiplo: Estudo Retrospectivo

Introdução: O mieloma múltiplo e caracterizado como uma neoplasia maligna plasmocitária com a proliferação anormal de plasmócitos clonais na medula óssea de etiologia desconhecida. Objetivo: Caracterizar os pacientes com mieloma múltiplo atendidos no Setor de Estômato-Odontologia e Prótese do INCA, por meio de dados sociodemográficos, clínicos, laboratoriais e radiográficos. Método: Estudo transversal retrospectivo de pacientes com diagnostico de mieloma múltiplo, no período de 2000 a 2018, que realizaram radiografia panorâmica no período do diagnóstico da doença. Os dados sociodemográficos e clinico-radiográficos da população em estudo foram coletados nos prontuários dos pacientes, armazenados em banco de dados, analisados de forma descritiva e submetidos ao teste não paramétrico X2 (qui-quadrado). Resultados: Na amostra final, foram totalizados 163 casos. A maioria era de homens (56,4%), brancos (55,8%), com idade ≤55 anos (54%), ensino fundamental incompleto (30,7%), não fumantes (54,6%) e não bebedores (54,6%). Havia lesões líticas em 46 pacientes (28,2%) com predileção pela mandíbula (82,6%; p=0,000). Houve maior frequência de margens parcialmente definidas (50,0%), não escleróticas (78,2%) e de aspecto unilocular (43,5%). Dos 46 pacientes que apresentaram lesão lítica maxilomandibular, 27 pacientes tinham >55 anos (p=0,042). Conclusão: Ha maior ocorrência de lesões ósseas na mandíbula quando comparada a maxila.

Whole-body magnetic resonance imaging (WBMRI) versus whole-body computed tomography (WBCT) for myeloma imaging and staging

Myeloma-associated bone disease (MBD) develops in about 80-90% of patients and severely affects their quality of life, as it accounts for the majority of mortality and morbidity. Imaging in multiple myeloma (MM) and MBD is of utmost importance in order to detect bone and bone marrow lesions as well as extraosseous soft-tissue masses and complications before the initiation of treatment. It is required for determination of the stage of disease and aids in the assessment of treatment response. Whole-body low-dose computed tomography (WBLDCT) is the key modality to establish the initial diagnosis of MM and is now recommended as reference standard procedure for the detection of lytic destruction in MBD. In contrast, whole-body magnetic resonance imaging (WBMRI) has higher sensitivity for the detection of focal and diffuse plasma cell infiltration patterns of the bone marrow and identifies them prior to osteolytic destruction. It is recommended for the evaluation of spinal and vertebral lesions, while functional, diffusion-weighted MRI (DWI-MRI) is a promising tool for the assessment of treatment response. This review addresses the current improvements and limitations of WBCT and WBMRI for diagnosis and staging in MM, underlining the fact that both modalities offer complementary information. It further summarizes the corresponding radiological findings and novel technological aspects of both modalities.

Extraosseous multiple myeloma: imaging spectrum in the abdomen and pelvis

Multiple myeloma represents a subset of plasma cell dyscrasias characterized by the proliferation of plasma cells typically in the bone marrow, representing approximately 1% of all cancers and 15% of hematologic malignancies. Often multiple myeloma is limited to the skeletal system; however, a small percentage (<5%) of patients will develop extraosseous manifestations. We review the current WHO classification of plasma cell dyscrasias and use multimodality imaging including US, CT, MRI, and PET-CT to illustrate the spectrum of extraosseous multiple myeloma in the abdomen and pelvis. Because extraosseous multiple myeloma is associated with a poorer prognosis and decreased survival, it is important for the radiologist to become familiar with a variety of extraosseous manifestations in the abdomen and pelvis, especially in a patient with a known diagnosis of multiple myeloma and the development of an abdominal or pelvic mass.

miR-148a controls metabolic programming and survival of mature CD19-negative plasma cells in mice

Long-lived antibody-secreting plasma cells are essential to establish humoral memory against pathogens. While a regulatory transcription factor network has been established in plasma cell differentiation, the regulatory role of miRNAs remains enigmatic. We have recently identified miR-148a as the most abundant miRNA in primary mouse and human plasma cells. To determine whether this plasma cell signature miRNA controls the in vivo development of B cells into long-lived plasma cells, we established mice with genomic, conditional, and inducible deletions of miR-148a. The analysis of miR-148a-deficient mice revealed reduced serum Ig, decreased numbers of newly formed plasmablasts and reduced CD19-negative, CD93-positive long-lived plasma cells. Transcriptome and metabolic analysis revealed an impaired glucose uptake, a reduced oxidative phosphorylation-based energy metabolism, and an altered abundance of homing receptors CXCR3 (increase) and CXCR4 (reduction) in miR-148a-deficient plasma cells. These findings support the role of miR-148a as a positive regulator of the maintenance of long-lived plasma cells.

Hematologic malignancies of the gastrointestinal luminal tract

Hematologic malignancies include several lymphoproliferative and myeloproliferative disorders, many of which are frequently encountered in current health care settings. These malignancies frequently affect the gastrointestinal (GI) tract, either by secondary extranodal or extramedullary extension to the GI tract, or as a primary process arising in the GI tract. In fact, the GI tract may represent the most common extranodal site of involvement in many of them, such as lymphoma. Furthermore, in the current era of improved cancer treatment and advanced transplant procedures with increased survival, it has been quite common to encounter GI involvement by these malignancies through the disease course. Post-transplant lymphoproliferative disorder following kidney transplantation, for example, very commonly involves the GI tract. Other conditions that can involve the GI tract include multiple myeloma, plasmacytoma, myeloid sarcoma, mastocytosis, and Castleman disease. Imaging diagnosis of these malignancies can be challenging, since they are much less common than primary GI cancers and both share many common imaging features as well. However, certain imaging features, particularly in combination with a matching clinical scenario, play a pivotal role in diagnosing these conditions and directing further evaluation. In this article, we review common and rare hematologic malignancies of the GI tract and discuss their pathophysiologic, clinical, and imaging features.

Multimodality imaging of indolent B cell lymphoma from diagnosis to transformation: what every radiologist should know

Indolent B cell lymphomas are a group of lymphoid malignancies characterized by their potential to undergo histologic transformation to aggressive lymphomas. While different subtypes of indolent B cell lymphomas demonstrate specific clinical and imaging features, histologic transformation can be suspected on cross-sectional imaging when disproportionate lymph node enlargement or new focal lesions in extranodal organs are seen. On PET/CT, transformed indolent lymphoma may show new or increased nodal FDG avidity or new FDG-avid lesions in different organs. In this article, we will (1) review the imaging features of different subtypes of indolent B cell lymphomas, (2) discuss the imaging features of histologic transformation, and (3) propose a diagnostic algorithm for transformed indolent lymphoma. The purpose of this review is to familiarize radiologists with the spectrum of clinical and imaging features of indolent B cell lymphomas and to define the role of imaging in raising concern for transformation and in guiding biopsy for confirmation.

Solitary Extramedullary Plasmacytoma of the Cricoid Cartilage-Case Report

Solitary plasmacytoma (SP) is an extremely rare form of hematologic malignancy that can be classified as solitary bone plasmacytoma or solitary extramedullary plasmacytoma. Here, we report a patient who presented with progressive shortness of breath and foreign body sensation in his throat. Fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG-PET/CT) demonstrated an abnormal FDG-avid soft tissue mass arising from the larynx involving the cricoid cartilage without additional suspicious lesions. Histology revealed an abundance of plasma cells; immunohistochemistry was positive for CD138 expression and lambda chains, and negative for CD20. Comprehensive imaging studies and panendoscopy of the ENT tract confirmed solitary disease involvement. Following additional systemic work-up, a diagnosis of extramedullary plasmacytoma was rendered. The patient underwent definitive radiotherapy using intensity-modulated radiation therapy (total dose of 46 Gy, divided in 23 fractions of 200 cGy). Serial PET/CT showed the stepwise resolution of abnormal FDG uptake and resolution of the cricoid cartilage lesion. With 22 months of follow-up, the patient remains free of disease. We describe the rare case of SP presenting as a FDG-avid hypermetabolic soft tissue mass in the cricoid cartilage, which should be considered in the differential diagnosis of laryngeal tumors. Of note, SP is radiosensitive; favorable outcome can be expected once treated with doses of 40–50 Gy. FDG PET/CT is helpful in diagnosis and response assessment for this disease.

miRNA meets plasma cells "How tiny RNAs control antibody responses"

We review the importance of small non-coding microRNAs for the generation of germinal center B cells and their differentiation in antibody-secreting plasma cells. In the last part, we briefly elucidate the role of microRNAs in some plasma cell disorders.

Solitary Plasmacytoma of the Mesentery: A Systematic Clinician's Diagnosis

INTRODUCTION

Plasmacytoma is an uncommon plasma cell neoplasm and its localized form is solitary plasmacytoma of the bone and solitary extramedullary plasmacytoma. Solitary plasmacytoma of the mesentery is extremely rare, reported only in a handful of cases.

CASE PRESENTATION

A 47-year-old man with nonspecific abdominal complains was found to have an ill-defined mass on his mesenteric root. Laparoscopic biopsy and stepwise histopathological examination revealed a mesenteric plasmacytoma, and extensive imaging and laboratory investigations led to the diagnosis of the solitary mesenteric plasmacytoma. The patient underwent definitive radiotherapy and remains under remission one year later.

DISCUSSION

Plasma cell dyscrasias include a variant of proliferative disease, characterized by clonal expansion of bone marrow plasma cells, producing a massive quantity of monoclonal immunoglobulin called paraprotein or M-protein. Solitary extramedullary plasmacytoma accounts for only 3-5% of all plasma cell neoplasms. Meticulous adherence to the established diagnostic criteria helps the clinician to set the correct, yet very unusual and unexpected diagnosis.