Amyloidosis: Review and CT Manifestations

Unconventional Strategies for Solid Organ Transplantation and Special Transplantation Scenarios

Solid organ transplantation is the only long-term therapeutic option for patients with end-organ failure but cadaveric and living donor transplant pools are unable to meet the demand for organ transplantation. Newer techniques, innovative strategies and altruistic donors can help bridge this wide gap between the number of organ donors and recipients. Domino liver transplantation, paired organ donation, and ABO incompatible transplants are some of the ways to ensure increased transplant organ availability. Split liver transplantation and ex vivo liver resection and auto transplantation are considered surgically challenging but are being done at tertiary transplant centers.

Tips and Tricks in Thoracic Radiology for Beginners: A Findings-Based Approach

This review has the purpose of illustrating schematically and comprehensively the key concepts for the beginner who approaches chest radiology for the first time. The approach to thoracic imaging may be challenging for the beginner due to the wide spectrum of diseases, their overlap, and the complexity of radiological findings. The first step consists of the proper assessment of the basic imaging findings. This review is divided into three main districts (mediastinum, pleura, focal and diffuse diseases of the lung parenchyma): the main findings will be discussed in a clinical scenario. Radiological tips and tricks, and relative clinical background, will be provided to orient the beginner toward the differential diagnoses of the main thoracic diseases.

Localized nasopharyngeal amyloidosis: A case report

Amyloidosis is a rare condition on its own but finding localized amyloidosis of a site such as the nasopharynx is an extremely rare condition with very few cases described in the literature. The condition occurs due to the accumulation of misfolded proteins in the extracellular space disrupting the cell architecture and causing eventual dysfunction. In this case report we discuss the pathophysiology, symptoms, and imaging findings of a patient initially thought to have giant cell arteritis, but who was found on CT to have a mass later determined to be localized nasopharyngeal amyloidosis. Evaluation will require biopsy as it is the gold standard, but there are many other tests and even reasons to consider the use of interventional radiology to sample other tissues rather than the primary target site for amyloid deposition in conjunction with nuclear imaging.

Imaging Review of Gastrointestinal Motility Disorders

The motor function of the gastrointestinal tract relies on the enteric nervous system, which includes neurons spanning from the esophagus to the internal anal sphincter. Disorders of gastrointestinal motility arise as a result of disease within the affected portion of the enteric nervous system and may be caused by a wide array of underlying diseases. The etiology of motility disorders may be primary or due to secondary causes related to infection or inflammation, congenital abnormalities, metabolic disturbances, systemic illness, or medication-related side effects. The symptoms of gastrointestinal dysmotility tend to be nonspecific and may cause diagnostic difficulty. Therefore, evaluation of motility disorders requires a combination of clinical, radiologic, and endoscopic or manometric testing. Radiologic studies including fluoroscopy, CT, MRI, and nuclear scintigraphy allow exclusion of alternative pathologic conditions and serve as adjuncts to endoscopy and manometry to determine the appropriate diagnosis. Additionally, radiologist understanding of clinical evaluation of motility disorders is necessary for guiding referring clinicians and appropriately imaging patients. New developments and advances in imaging techniques have allowed improved assessment and diagnosis of motility disorders, which will continue to improve patient treatment options. Online supplemental material is available for this article. ^©RSNA, 2022.

A Systematic Approach to Diagnosing Arthritis Based on Radiological Imaging

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Radiology plays key roles in diagnosis of arthritis. We herein suggest an algorithmic approach to diagnosing arthritis. First, the number of joint involvements is reviewed. Monoarticular arthritis includes septic arthritis, pigmented villonodular synovitis, and synovial chondromatosis. Second, polyarticular arthritis can be categorized by its characteristics: erosive, productive and mixed. Erosive disease includes rheumatoid arthritis, hemophilia, and amyloidosis while productive disease includes osteoarthritis, and hemochromatosis. Third, mixed diseases are subcategorized by symmetricity. Ankylosing spondylitis and inflammatory bowel disease related arthritis affect joints symmetrically while psoriatic arthritis, reactive arthritis, and crystalline arthropathy are asymmetric. Adjacent soft tissue density, periostitis, and bone density are ancillary findings that can be used as additional differential diagnostic clues. The final step in identifying the type of arthritis is to check whether the location is a site frequently affected by one particular disease over another. This systematic approach would be helpful for radiologist to diagnose arthritis.

Pictorial review of computed tomography features of diffuse cystic lung disease

Diffuse cystic lung disease represents a diverse group of uncommon disorders that has been increasingly diagnosed due to the increasing use of computed tomography. It poses a frequent diagnostic challenge to radiologists due to the similar clinical and radiological features these diseases share. This pictorial review includes selected cases from the Hospital Authority New Territories West Cluster (NTWC) in Hong Kong from the past 3 years. It will illustrate the spectrum of diffuse cystic lung diseases, including some rarer entities in our locality, and identify the pertinent differentiating imaging features on CT. A flowchart to summarize these features is provided at the end to aid in diagnosis.

Amyloidosis: Multisystem Spectrum of Disease with Pathologic Correlation

Amyloidosis is a group of conditions defined by extracellular deposition of insoluble proteins that can lead to multiorgan dysfunction and failure. The systemic form of the disease is often associated with a plasma cell dyscrasia but may also occur in the setting of chronic inflammation, long-term dialysis, malignancy, or multiple hereditary conditions. Localized forms of the disease most often involve the skin, tracheobronchial tree, and urinary tract and typically require tissue sampling for diagnosis, as they may mimic many conditions including malignancy at imaging alone. Advancements in MRI and nuclear medicine have provided greater specificity for the diagnosis of amyloidosis involving the central nervous system and heart, potentially obviating the need for biopsy of the affected organ in certain circumstances. Specifically, a combination of characteristic findings at noninvasive cardiac MRI and skeletal scintigraphy in patients without an underlying plasma cell dyscrasia is diagnostic for cardiac transthyretin amyloidosis. Histologically, the presence of amyloid is denoted by staining with Congo red and a characteristic apple green birefringence under polarized light microscopy. The imaging features of amyloid vary across each organ system but share some common patterns, such as soft-tissue infiltration and calcification, that may suggest the diagnosis in the appropriate clinical context. The availability of novel therapeutics that target amyloid protein fibrils such as transthyretin highlights the importance of early diagnosis. Online supplemental material is available for this article. ^©RSNA, 2021.

Localized plantar amyloidosis: case report and review of the literature

Amyloidosis may be hereditary or acquired and the deposits can be focal, localized, or systemic in distribution. A discrete mass of amyloid deposition is called an amyloidoma and is the least common presentation. Soft tissue amyloidoma in an extremity is exceedingly rare. Amyloidomas can mimic malignant neoplasms both clinically and radiologically. We report a case of an amyloidoma in the foot, which has not been previously described. Clinical history, pathology, and immunohistochemistry and appearance by MRI are described. Knowledge of this atypical lesion, in its various forms, is important for experts in musculoskeletal radiology, pathology, surgery, and oncology to appreciate as it can prevent confusion with more sinister disease processes such as malignancy. Early recognition can help guide appropriate management in a timely fashion.

Fluorodeoxyglucose PET/CT of Arthritis in Rheumatic Diseases: A Pictorial Review

Rheumatic diseases are various painful conditions that affect joints, bones, cartilage, tendons, ligaments, and muscles. Arthritis is a typical condition of rheumatic disease. Although rheumatoid arthritis is a representative rheumatic disease, various diseases other than rheumatoid arthritis can also affect joints, and differential diagnosis of rheumatic diseases is often difficult owing to the similar clinical manifestations. However, accurate diagnosis is crucial for an appropriate treatment strategy. The utility of fluorine 18 fluorodeoxyglucose (FDG) PET/CT has been established, and it is widely used for assessing malignancies. In addition to accumulating in tumor cells, FDG also accumulates in inflammatory tissue, allowing FDG PET/CT to demonstrate arthritis. PET/CT allows evaluation of whole-body articular and extra-articular lesions in one examination, representing a key advantage over US and MRI, which allow assessment of only a few regions because of their limited field of view. Although FDG PET/CT is sensitive for detecting inflammatory lesions, the uptake itself is nonspecific; therefore, knowledge of characteristic uptake patterns is necessary to narrow the differential diagnosis in rheumatic disease. Furthermore, pathognomonic extra-articular findings such as vasculitis, skin lesions, lymphadenopathy, and chondritis play an important role in achieving accurate diagnosis. The authors present the FDG PET/CT appearances of (a) rheumatoid arthritis and allied disorders (polymyalgia rheumatica, remitting seronegative symmetrical synovitis with pitting edema, adult-onset Still disease), (b) spondyloarthritis (ankylosing spondylitis, psoriatic arthritis, reactive arthritis, inflammatory bowel disease arthritis, SAPHO [synovitis, acne, pustulosis, hyperostosis, and osteitis] syndrome, chronic recurrent multifocal osteomyelitis), and (c) miscellaneous systemic disorders with arthropathy (relapsing polychondritis, multicentric reticulohistiocytosis, amyloidosis, sarcoidosis, hemophilia). ^©RSNA, 2020.

Localised laryngotracheal amyloidosis: a differential diagnosis not to forget

We present a case of multifocal laryngotracheal amyloidosis (LTA) in a 43-year-old man with persistent and progressive dysphonia and dyspnoea, and a first inconclusive histology. Although laryngeal amyloidosis accounts for fewer than 1% of all benign laryngeal tumours, it is in fact the most common site of amyloid deposition in the head, neck and respiratory tract. The clinical scenario is non-specific and diagnosis depends on a high degree of suspicion and on histology. Imaging is useful in mapping lesions, which are often more extensive than they appear during laryngoscopy. Despite being a benign entity, the prognosis is variable with a high-rate and long-latency recurrences, requiring long-term follow-up.

CT and MRI Features of Localized Peritumoral Amyloidosis in a Patient with Head and Neck Mucosa-Associated Lymphoid Tissue Lymphoma: A Case Report

Amyloidosis has been reported to be associated with non-Hodgkin lymphoma. Amyloidosis and lymphoma can be related in two ways: lymphoma-associated systemic amyloidosis and peritumoral amyloidosis with lymphoma. We report a rare case of peritumoral amyloidosis in a patient with head and neck mucosa-associated lymphoid tissue lymphoma. On CT, the oropharyngeal mass showed an irregularly shaped soft-tissue density with multifocal amorphous calcifications and heterogeneous enhancement. On MRI, the mass showed heterogeneous low signal intensity on both T1- and T2-weighted images. On contrast-enhanced MR images, the mass showed good enhancement with several inner non-enhancing foci. Concurrent pathologies, such as peritumoral amyloidosis, should be considered when calcifications are noted in patients with pre-treatment lymphoma.

A Stepwise Diagnostic Approach to Cystic Lung Diseases for Radiologists

Lung cysts are commonly seen on computed tomography (CT), and cystic lung diseases show a wide disease spectrum. Thus, correct diagnosis of cystic lung diseases is a challenge for radiologists. As the first diagnostic step, cysts should be distinguished from cavities, bullae, pneumatocele, emphysema, honeycombing, and cystic bronchiectasis. Second, cysts can be categorized as single/localized versus multiple/diffuse. Solitary/localized cysts include incidental cysts and congenital cystic diseases. Multiple/diffuse cysts can be further categorized according to the presence or absence of associated radiologic findings. Multiple/diffuse cysts without associated findings include lymphangioleiomyomatosis and Birt-Hogg-Dubé syndrome. Multiple/diffuse cysts may be associated with ground-glass opacity or small nodules. Multiple/diffuse cysts with nodules include Langerhans cell histiocytosis, cystic metastasis, and amyloidosis. Multiple/diffuse cysts with ground-glass opacity include pneumocystis pneumonia, desquamative interstitial pneumonia, and lymphocytic interstitial pneumonia. This stepwise radiologic diagnostic approach can be helpful in reaching a correct diagnosis for various cystic lung diseases.

Cystic Interstitial Lung Diseases: A Pictorial Review and a Practical Guide for the Radiologist

A cyst is a round circumscribed area of low attenuation, surrounded by epithelial or fibrous wall. Cysts can frequently occur on chest computed tomography (CT) and high-resolution computed tomography (HRCT); multiple parenchymal cysts of the lungs are the most typical feature of cystic lung interstitial diseases, characterizing a wide spectrum of diseases—ranging from isolated lung disorders up to diffuse pulmonary diseases. The aim of this review is to analyze scientific literature about cystic lung interstitial diseases and to provide a practical guide for radiologists, focusing on the main morphological features of pulmonary cysts: size, shape, borders, wall, location, and distribution. These features are shown on free-hand drawings and related to HRCT images, in order to help radiologists pursue the correct differential diagnosis between similar conditions.

Mesenteric Amyloidosis: Radiologic Imaging with Pathologic Correlation

Amyloidosis is a rare disease that is characterized by abnormal deposition of amyloid proteins in tissues, resulting in local, or systemic disease. When localized, it can present as an amyloidoma. We report a case of mesenteric amyloidosis in an 80-year-old male who was found to have an incidental mesenteric mass that was biopsy-proven to represent non-light chain amyloid tissue.

Morphometric changes and imaging findings of diffuse liver disease in relation to intrahepatic hemodynamics

Diffuse hepatic diseases have a variety of etiologies, with each showing characteristic morphometric changes. These changes are closely related to micro- and macro-level intrahepatic hemodynamics, in addition to the specific underlying pathophysiology. Short-term disorders in intrahepatic hemodynamics caused by each pathophysiological condition are compensated for by the balance of blood perfusion systems using potential trans-sinusoidal, transversal, and transplexal routes of communication (micro-hemodynamics), while long-term alterations to the intrahepatic hemodynamics result in an increase in total hepatic vascular resistance. Blood flow disorders induced by this increased vascular resistance elicit hepatic cellular necrosis and fibrosis. These changes should be uniformly widespread throughout the whole liver. However, morphometric changes do not occur uniformly, with shrinkage or enlargement not occurring homogeneously. Against this background, several macro-intrahepatic hemodynamic effects arise, such as asymmetrical and complicating morphometric structures of the liver, intricate anatomy of portal venous flow and hepatic venous drainage, and zonal differentiation between central and peripheral zones. These hemodynamic factors and pathophysiological changes are related to characteristic morphometric changes in a complicated manner, based on the combination of selective atrophy and compensatory hypertrophy (atrophy-hypertrophy complex). These changes can be clearly depicted on CT and MR imaging.

Sternoclavicular Amyloid Arthropathy in a Patient With End-Stage Renal Disease

Amyloidosis is an extracellular deposition of amyloid located in different organs or in a systemic distribution. We present a case of a 78 year-old male with hemodyalisis assosciated amyloidosisis involving the right sternoclavicular joint. Clinical and imaging implications are described.

Malabsorption Syndromes, Vasculitis, and Other Uncommon Diseases

MR enterography is frequently ordered for patients with suspected small bowel disorders. In this article, disease-causing malabsorption, vasculitides, and some of the less common small bowel diseases are reviewed. The clinical presentations, diagnostic criteria, and imaging findings of these diseases are discussed. Because the imaging findings in several small bowel diseases are nonspecific and/or overlap, radiologists must correlate clinical data with imaging to develop a narrower differential diagnosis. The unique or characteristic findings in certain diseases are also emphasized.

Primary Gastrointestinal Amyloidosis: An Unusual Cause of Acute Intestinal Pseudo-Obstruction

Amyloidosis of the gastrointestinal tract is an uncommon disorder characterized by the extracellular deposition of an abnormal fibrillar protein. It is rarely proven by biopsy. Amyloid deposition interferes with organ structure and its function. We report a case of a 64-year-old male who presented with severe colicky pain, unable to pass feces, and progressive abdominal distension for 2 days. Physical examination revealed marked abdominal distension, visible peristalsis, high-pitched hyperactive bowel sounds, and generalized tenderness. Plain abdominal radiograph showed markedly diffuse disproportional dilatation of the small bowel with different heights of air-fluid levels in the same loop. Abdominal computed tomography showed an evidence of small bowel obstruction, which revealed no gross mass or cause of obstruction, but long segment narrowing of the terminal ileum was seen. Ileocolonoscopy showed diffuse edematous mucosa of the ileum without mechanical obstruction but loss of normal bowel peristalsis. A random biopsy of the ileum was performed for pathological diagnosis, which reported extensive deposits of amorphous material within the muscle layers and in the submucosal vessels that stained strongly with Congo red and displayed the typical apple-green birefringence of amyloid protein when viewed under plane polarized light. Serum electrophoretic tests disclosed a monoclonal band of IgG-kappa monoclonal protein. His clinical symptoms improved after receiving chemotherapy with melphalan and prednisolone. Our case illustrated the rare cause of acute intestinal obstruction which mimicked a surgical condition. Primary intestinal amyloidosis should be in a differential diagnosis in patients without a demonstrated cause of obstruction.

MR enterography: what is next after Crohn's disease?

Within the gastrointestinal system, the small bowel represents the most difficult site to approach with imaging modalities. During the last decades, magnetic resonance enterography has reached an increasing interest, up to be considered an essential part in the diagnostic framework of Crohn's disease patients. Nevertheless, the distention of the intestinal loops provided by the administration of oral contrast medium, the possibility of a dynamic evaluation, and the lack of radiation exposure are huge advantages that can be exploited for the assessment of other clinical conditions affecting the small bowel. Physicians and radiologists should be aware of the possibilities offered by this technique, looking at it as a trustful alternative to the well-worn radiological examinations. In this respect, the purpose of this work is to show some uncommon clinical conditions that can be assessed with magnetic resonance enterography and that fall within the various differential diagnosis of the intestinal disorders.

A rare case of omental cake

Systemic amyloidosis is normally detected on histology by deposition of amyloid into soft tissue organs. Omental and peritoneal involvement are rare manifestations of the disease. The differential diagnosis for omental and peritoneal disease does not, therefore, normally include amyloid.

Radiologic Findings in Polyarticular Amyloid Arthropathy and Myopathy in Multiple Myeloma: A Case Report

Patient: Male, 56

Final Diagnosis: Amyloid arthropathy and myopathy

Symptoms: Polyarthralgia

Medication: —

Clinical Procedure: —

Specialty: Radiology

Small Bowel Amyloidosis

PURPOSE OF REVIEW

The goal of this paper is to review the literature on small bowel amyloidosis. Our review focuses on the underlying etiology, histopathology, clinical features, endoscopic and radiologic findings, and the mainstay of management.

RECENT FINDINGS

The latest research shows changing epidemiological trends of different types of amyloidosis. It also reveals a better understanding of its pathophysiology and shows improvement in treatment outcomes. Amyloidosis is a group of diseases of multiple etiologies and clinical presentations. It is characterized by pathological deposition of insoluble fibrillar proteins within various organs leading to disruption of their structure and function. The classification of amyloidosis includes primary, secondary, dialysis-related, senile, and hereditary. Amyloidosis can be systemic or localized. The incidence of AA amyloidosis is declining in frequency. If the gastrointestinal (GI) tract is involved, the small intestine is the most commonly affected site. Overall, outcomes among patients with newly diagnosed amyloidosis have improved. This article focuses on small bowel amyloidosis.

Measurement of liver and spleen interstitial volume in patients with systemic amyloid light-chain amyloidosis using equilibrium contrast CT

OBJECTIVES

To investigate equilibrium contrast-enhanced CT (EQ-CT) measurement of extracellular volume fraction (ECV) in patients with systemic amyloid light-chain (AL) amyloidosis, testing the hypothesis that ECV becomes elevated in the liver and spleen and ECV correlates with other estimates of organ amyloid burden.

METHODS

26 patients with AL amyloidosis underwent EQ-CT, and ECV was measured in the liver and spleen. Patients also underwent serum amyloid P (SAP) component scintigraphy with grading of liver and spleen involvement. Mann-Whitney U test was used to test for a difference between patients with amyloid deposition (SAP grade 1-3) and those without (SAP grade 0). Variation in ECV across SAP grades was assessed using the Kruskal-Wallis test and association between ECV and SAP grades with Spearman correlation.

RESULTS

Mean ECV in the spleen and liver was significantly greater (p < 0.0005) in amyloidotic organs (SAP grade 1-3) [spleen, liver: 0.430, 0.375] compared with healthy tissues [spleen, liver: 0.304, 0.269]. ECV increased with increasing amyloid burden, showing positive correlation with SAP grade in both the liver (r = 0.758) and spleen (r = 0.867).

CONCLUSION

In patients with systemic AL amyloidosis, EQ-CT can demonstrate increased spleen and liver ECV, which is associated with amyloid disease burden.

The Lung in Dysregulated States of Humoral Immunity

In common variable immunodeficiency, lung manifestations are related to different mechanisms: recurrent pneumonias due to encapsulated bacteria responsible for diffuse bronchiectasis, diffuse infiltrative pneumonia with various patterns, and lymphomas, mostly B cell extranodal non-Hodgkin type. The diagnosis relies on significant serum Ig deficiency and the exclusion of any primary or secondary cause. Histopathology may be needed. Immunoglobulin (IgG) replacement is crucial to prevent infections and bronchiectasis. IgG4-related respiratory disease, often associated with extrapulmonary localizations, presents with solitary nodules or masses, diffuse interstitial lung diseases, bronchiolitis, lymphadenopathy, and pleural or pericardial involvement. Diagnosis relies on international criteria including serum IgG4 dosage and significantly increased IgG4/IgG plasma cells ratio in pathologically suggestive biopsy. Respiratory amyloidosis presents with tracheobronchial, nodular, and cystic or diffuse interstitial lung infiltration. Usually of AL (amyloid light chain) subtype, it may be localized or systemic, primary or secondary to a lymphoproliferative process. Very rare other diseases due to nonamyloid IgG deposits are described. Among the various lung manifestations of dysregulated states of humoral immunity, this article covers only those associated with the common variable immunodeficiency, IgG4-related disease, amyloidosis, and pulmonary light-chain deposition disease. Autoimmune connective-vascular tissue diseases or lymphoproliferative disorders are addressed in other chapters of this issue.

Hepatic Amyloidosis: Something That Can camouflage and Deceive our Perception!

Amyloidosis is a multi-systemic diffusely infiltrating disease due to extracellular deposition of protein-mucopolysaccharide complexes. The type of protein deposited determines the subgroup of amyloid. Hepatic amyloidosis is a rare infiltrating disease affecting the hepatic parenchyma. A wide range of clinical presentation and atypical imaging findings delay the diagnosis of amyloidosis, while tissue biopsy demonstrating amyloid deposits is vital for a definitive diagnosis.

Case 244: Systemic Amyloidosis-A Complication of Waldenström Macroglobulinemia

History A 68-year-old man was admitted to the hospital for work-up because of generalized fatigue, anorexia, chronic diarrhea, and weight loss. Laboratory work-up revealed an erythrocyte sedimentation rate of 58 mm/h (reference range, 3-23 mm/h), a hemoglobin level of 14.1 g/dL (reference range, 13.8-17.5 g/dL), a leukocyte count of 8.1 × 10⁹/L (reference range, [3.4-9.7] × 10⁹/L), a platelet count of 223 × 10⁹/L (reference range, [158-424] × 10⁹/L), an alkaline phosphatase level of 85 U/L (1.42 μkat/L) (normal level, <142 U/L [2.37 μkat/L]), a serum creatinine level of 93 μmol/L (reference range, 79-125 μmol/L), a serum total protein level of 82 g/L (reference range, 66-81 g/L), a serum albumin level of 39.3 g/L (reference range, 40.2-47.6 g/L), an albumin-to-globulin ratio (a test showing relative amounts of major plasma proteins) of 0.92 (reference range, 0.8-2.0), a urine protein level of 15 mg/dL (normal level, <20 mg/dL), a total serum calcium level of 2.46 mmol/L (reference range, 2.14-2.53 mmol/L), and a carcinoembryonic antigen value of 2.69 μg/L (normal value, <3.4 μg/L). Serology findings were negative for celiac disease. Thyroid function was normal, as were 5-hydroxyindoleacetic acid and chromogranin A levels. Initial radiologic examination included chest radiography and plain abdominal erect radiography. Gastrointestinal endoscopy was performed to rule out inflammatory bowel disease or gastrointestinal neoplasm as a cause of chronic diarrhea. Endoscopic mucosal resection of two polyps from the cardia and duodenal bulb was performed during esophagogastroduodenoscopy, but histologic findings at hematoxylin-eosin staining were normal. Colonoscopy revealed diverticulosis involving the entire colon. Serum immunoelectrophoresis showed a monoclonal band, which was confirmed to be immunoglobulin Mλ at immunofixation. After histologic analysis of the bone marrow biopsy specimen, diagnosis of Waldenström macroglobulinemia was established, and computed tomography (CT) of the thorax, abdomen, and pelvis was requested to depict lymphadenopathy and organomegaly. On the basis of CT findings, two more specimens considered highly sensitive for the CT diagnosis were obtained via minimally invasive biopsy, but the results were negative. Magnetic resonance (MR) imaging was performed a year later to control the progression of CT findings.

Spectrum of Benign Articular and Periarticular Findings at FDG PET/CT

Whole-body fluorine 18 fluorodeoxyglucose (FDG) positron-emission tomography (PET)/computed tomography (CT) is performed primarily for oncologic indications; however, FDG uptake is not specific for malignancy. Herein we focus on causes of increased FDG uptake in and around joints, as lesions in these locations are commonly benign. A combination of primary intra-articular processes and osseous processes that may occur near the joint space will be discussed. Causes of intra-articular and periarticular increased FDG activity can be broadly divided into infectious, inflammatory, degenerative, and benign neoplastic categories. A familiarity with the full range of these processes is important to avoid misinterpretation, in turn decreasing unnecessary follow-up studies, procedures, and treatments. Differentiation from malignancy is often possible on the basis of a different level of FDG activity, divergent response to therapy, or differing changes over time, in comparison with a patient's known primary cancer. Recognizing an intra-articular lesion location can also be critical, as intra-articular metastases are rare. In some cases, benign FDG-avid articular and periarticular entities have a specific appearance at FDG PET/CT and a correct diagnosis may be made without any additional workup. In most other cases, comparison with prior studies and/or additional imaging can afford an accurate diagnosis. This review is meant to introduce the reader to a spectrum of benign FDG-avid articular and periarticular processes that may be encountered at oncologic FDG PET/CT to increase confidence and diagnostic accuracy. (©)RSNA, 2016.

Primary systemic amyloidosis: imaging interpretation of this complex multisystemic disease

This report highlights the diagnostic complexities involved in the case of a 63-year-old female who presented with a non-productive cough and shortness of breath on exertion. Initial chest radiograph demonstrated generalized abnormal interstitial lung markings with thickened peripheral septal lines. Further characterization was sought by CT scan of the chest, and given the possibility of lymphangitic carcinomatosis, a CT scan of the abdomen and pelvis was also performed. The CT scan findings revealed septal line thickening, abnormal omental soft tissue with calcified deposits and wall thickening of the stomach and proximal duodenum. A preliminary differential diagnosis of peritoneal carcinomatosis was made, but cancer markers were equivocal. A CT-guided biopsy of the “omental cake” was non-diagnostic, hence formal biopsy via laparoscopy was undertaken. While awaiting the results, the patient was readmitted with acute haematemesis. Gastric and duodenal biopsies from the endoscopic assessment were positive for Congo red stain and birefringent under polarizsed light, which was consistent with amyloidosis. Histology from the omental biopsies and additional haematological tests concurred. The patient was diagnosed with advanced systemic amyloid light-chain amyloidosis comprising diffuse pulmonary amyloidosis, calcified omental soft tissue deposits, and extensive soft tissue amyloid with cardiac and gastrointestinal involvement. We discuss the spectrum of differential diagnoses posed by the imaging findings and the difficulties faced in interpreting this complex case of systemic amyloidosis.

Multimodality Imaging Including PET/CT in a Patient with Amyloid Arthropathy and Multiple Myeloma

We report a case of amyloid arthropathy in a patient with multiple myeloma. Amyloid arthropathy is a very rare condition that may be associated with multiple myeloma. It presented in our patient as soft tissue masses around joints and eroding into adjacent bones. We found it to be hypermetabolic on fused positron emission tomography and computed tomographic scanning.

Gastrointestinal manifestations of systemic disease: a multimodality review

Systemic diseases have many different presentations, including imaging findings in the bowel. Recognizing the imaging findings in these diseases is important in making the correct diagnosis. Although certain imaging features overlap, knowledge of specific findings along with the clinical presentation aid in narrowing the differential or in making an imaging diagnosis. The pictorial review will focus on the gastrointestinal manifestations of systemic diseases, including amyloidosis, angiotensin converter enzyme inhibitor-induced angioedema, celiac sprue, distal intestinal obstruction syndrome, graft-versus-host disease, hemolytic uremic syndrome, hemophilia, Henoch-Schönlein purpura, intestinal lymphangiectasia, mastocytosis, scleroderma, systemic lupus erythematosus, Wegener's granulomatosis, and Whipple's disease. The aforementioned diseases can be subdivided based upon the underlying process leading to the disease. The diseases discussed are categorized into autoimmune, infiltrative, treatment related, congenital/hereditary, and infectious etiologies.

Thoracic lymphadenopathy in benign diseases: A state of the art review

Lymphadenopathy is a common radiological finding in many thoracic diseases and may be caused by a variety of infectious, inflammatory, and neoplastic conditions. This review aims to describe the patterns of mediastinal and hilar lymphadenopathy found in benign diseases in immunocompetent patients. Computed tomography is the method of choice for the evaluation of lymphadenopathy, as it is able to demonstrate increased size of individual nodes, abnormalities of the interface between the mediastinum and lung, invasion of surrounding fat, coalescence of adjacent nodes, obliteration of the mediastinal fat, and hypo- and hyperdensity in lymph nodes. Intravenous contrast enhancement may be needed to help distinguish nodes from vessels. The most frequent infections resulting in this finding are tuberculosis and fungal disease (particularly histoplasmosis and coccidioidomycosis). Sarcoidosis is a relatively frequent cause of lymphadenopathy in young adults, and can be distinguished from other diseases - especially when enlarged lymph nodes are found to be multiple and symmetrical. Other conditions discussed in this review are silicosis, drug reactions, amyloidosis, heart failure, Castleman's disease, viral infections, and chronic obstructive pulmonary disease.

Imaging features of haematological malignancies of kidneys

Haematological malignancies are relatively uncommon neoplasms of kidneys. Nevertheless, the incidence of these neoplasms is increasing, partly due to more widespread use of computed tomography and magnetic resonance imaging. This article discusses the clinical and imaging features of renal lymphoma, leukaemia, extra-osseous multiple myeloma, and post-transplant lymphoproliferative disorder. Although there is overlap of imaging features with other more common malignancies, such as transitional and renal cell cancers, the combination of imaging findings and the appropriate clinical picture should allow the radiologist to raise a provisional diagnosis of a haematological neoplasm. This has management implications including the preference for image-guided core biopsies and a shift towards medical rather than surgical therapy.

Use of polarized light microscopy is essential in the efficient diagnosis of respiratory amyloidosis and could decrease disease prevalence

INTRODUCTION

Primary tracheobronchial amyloidosis (TBA) is a rare disease of unknown etiology, with a high misdiagnosis rate. The current gold standard diagnostic criteria require double-positive results for Congo red staining and polarized light microscopy examination.

OBJECTIVES

The aim of the present report was to examine the diagnostic value of polarized light microscopy in TBA diagnosis in China.

METHODS

Thirteen cases from the Shandong University Qilu Hospital were reviewed. Polarized light microscopic examination was conducted after searching for cases with positive Congo red staining.

RESULTS

Among the 13 patients, eight displayed yellow-green birefringence body with polarized light microscopic examination. This result indicated a false-positive rate of 38.5% with Congo red staining used as the single criteria for TBA diagnosis. After reviewing the Chinese literature and selecting 104 reported cases of TBA in China, we found that diagnosis with the gold standard was confirmed in <30% patients, which may lead to misdiagnosis and delayed treatment.

CONCLUSION

The universal use of polarized light microscopy in China is currently limited, and there is a big gap from the international diagnosis standards. There is a need to include polarized light microscopy in routine TBA diagnosis to reduce the misdiagnosis rate, and achieve optimal treatment.

Respiratory Tract Amyloidosis. State-of-the-Art Review with a Focus on Pulmonary Involvement

Amyloidosis is a constellation of disease entities characterized by abnormal extracellular deposition and accumulation of protein and protein derivatives, which show apple-green birefringence when stained with Congo red and viewed under polarized light. Amyloid can infiltrate virtually all organ systems and can display multiple and diverse imaging findings. Pathologically, respiratory involvement occurs in 50 % of patients with amyloidosis, and its clinical signs and symptoms vary depending on whether the disease is systemic or localized. The four main patterns of respiratory tract involvement are tracheobronchial, nodular parenchymal, diffuse alveolar septal, and lymphatic. Imaging findings of amyloidosis are nonspecific and vary in each pattern; knowledge about the disease impairment type is thus very important, and amyloidosis should be considered in the differential diagnosis of other very common diseases, such as infectious diseases, neoplasms, and vasculitis. This literature review describes the main clinical and imaging manifestations of amyloidosis, focusing on respiratory tract involvement and differential diagnosis.

[Mediastinal primary amyloidosis of pseudo tumor appearance]

L'amylose primitive médiastinale isolée est rare et de diagnostic difficile. Nous rapportons l'observation d'un patient âgé de 41 ans ayant présenté une dyspnée et des crachats hémoptoïques. A l'examen physique il n'avait pas d'hypotension orthostatique. Les aires ganglionnaires périphériques étaient libres. La tomodensitométrie thoracique a objectivé un magma d'adénopathies médiastinales réalisant une masse de 45 mm x 60 mm. L'examen anatomopathologique d'une biopsie ganglionnaire guidée par médiastinoscopie a conclut a une amylose médiastinale de type AL. Il n'avait pas d'autres localisations amyloïdes. Un myélome multiple a été éliminé. Le diagnostic d'amylose primitive médiastinale de type AL a été retenu. Le traitement s'est basé sur des cures de Melphalan-prednisone. La chirurgie était évitée vu le risque hémorragique élevé. L’évolution était marquée par l'amélioration de la dyspnée, la disparition de l'hémoptysie et la diminution de la taille de la masse ganglionnaire devenant 25 mm x 20 mm.

Osteolytic femoral lesion detected by sonography in a case of light chain deposition disease

We describe a case of light chain deposition disease presenting as worsening of renal failure with a lytic femoral bone lesion discovered by sonography. Although sonography cannot be considered to be the test of choice in evaluating multiple myeloma, this technique may allow the detection and the biopsy of osteolytic bone lesions, particularly in accessible locations. Differential diagnosis is discussed.

Tuberculosis of the genitourinary system-Urinary tract tuberculosis: Renal tuberculosis-Part II

This article reviews the computed tomography and magnetic resonance imaging (MRI) features of renal tuberculosis (TB), including TB in transplant recipients and immunocompromised patients. Multi detector computed tomography (MDCT) forms the mainstay of cross-sectional imaging in renal TB. It can easily identify calcification, renal scars, mass lesions, and urothelial thickening. The combination of uneven caliectasis, with urothelial thickening and lack of pelvic dilatation, can also be demonstrated on MDCT. MRI is a sensitive modality for demonstration of features of renal TB, including tissue edema, asymmetric perinephric fat stranding, and thickening of Gerota's fascia, all of which may be clues to focal pyelonephritis of tuberculous origin. Diffusion-weighted MR imaging with apparent diffusion coefficient (ADC) values may help in differentiating hydronephrosis from pyonephrosis. ADC values also have the potential to serve as a sensitive non-invasive biomarker of renal fibrosis. Immunocompromised patients are at increased risk of renal TB. In transplant patients, renal TB, including tuberculous interstitial nephritis, is an important cause of graft dysfunction. Renal TB in patients with HIV more often shows greater parenchymal affection, with poorly formed granulomas and relatively less frequent findings of caseation and stenosis. Atypical mycobacterial infections are also more common in immunocompromised patients.