Hemophagocytic lymphohistiocytosis in children: abdominal US findings within 1 week of presentation

Pediatric splenic infarction: Assessment of associated clinical conditions and outcome

Pediatric splenic infarction (SI) is rare yet clinically significant. Publications regarding this complication are mostly limited to case reports. This is a retrospective study examining SI etiology, clinical presentation, management, and outcomes among children. Twenty-two patients (median age: 7.9 years) were included, mostly with pre-existing hematological diseases. Splenomegaly (72%), thrombocytopenia, and anemia were common. Most of the patients did not receive antithrombotic therapy yet only two patients experienced recurrences. During follow up 36% of patients died, however no fatalities were attributed to thrombotic or bleeding complications.

Emerging Trends in Radionuclide Imaging of Infection and Inflammation in Pediatrics: Focus on FDG PET/CT and Immune Reactivity

The most common indication for ¹⁸F-FDG PET/CT is tumor imaging, which may be performed for initial diagnosis, staging, therapeutic response monitoring, surveillance, or suspected recurrence. In the routine practice of pediatric nuclear medicine, most infectious, inflammatory, and autoimmune processes that are detected on ¹⁸F-FDG PET/CT imaging - except for imaging in fever or inflammation of unknown origin - are coincidental and not the main indication for image acquisition. However, interpreting these "coincidental" findings is of utmost importance to avoid erroneously attributing these findings to a neoplastic process. We review the recent literature on fever of unknown origin as well as inflammation of unknown origin in pediatrics and then focus on the ¹⁸F FDG PET/CT imaging findings seen in two specific entities with increased immune reactivity: hemophagocytic lymphohistiocytosis syndrome and the immune-related adverse events associated with checkpoint inhibitors. We will subsequently close with two sections highlighting related topics and relevant references for further reading.

Clinical features and prognostic factors of adult secondary hemophagocytic syndrome: Analysis of 47 cases

This study aimed to investigate the relationship between clinical features and prognosis of adult secondary hemophagocytic syndrome (HPS).A retrospective analysis was conducted on the pathogenesis, clinical manifestations, laboratory examinations, treatment options, and prognosis of 47 patients with adult secondary HPS diagnosed from January 2013 to December 2015.The average age at disease onset was (46.26 ± 18.98) years with a male:female ratio of 1:1.14. Thirteen patients died, with the highest mortality rate in patients with HPS underlying blood system malignancy (33.33%, 2/6). The mortality rate in patients with HPS underlying autoimmune disorders was the lowest (18.75%, 3/16). The Kaplan-Meier analysis indicated that signs of hemorrhage, pulmonary and nervous system involvement, serous effusion, and decrease in the blood platelet count were associated with death. The Cox regression analysis revealed that signs of hemorrhage, pulmonary involvement, serous effusion, and nervous system involvement were independent risk factors of patient death.Adult secondary HPS has multiple etiologies and diversified clinical features. The risk of death increases in patients with signs of hemorrhage, serous effusion, pulmonary involvement, and nervous system involvement.

Spectrum of Xanthogranulomatous Processes in the Abdomen and Pelvis: A Pictorial Review of Infectious, Inflammatory, and Proliferative Responses

OBJECTIVE

Xanthogranulomatous (XG) processes are rare inflammatory conditions with the characteristic pathologic feature of lipid-laden macrophages or histiocyte cells. Imaging findings are nonspecific and can simulate aggressive neoplastic processes. XG processes can be caused by infection, inflammation, histolytic process, or an inherited lysosomal disorder. XG infectious processes are mainly seen in cholecystitis and pyelonephritis, but several other organs can also be involved. Histiocytic processes can be divided into Langerhans and non-Langerhans cell histiocytosis. The non-Langerhans cell histiocytosis entities include Erdheim-Chester disease, Rosai-Dorfman disease, juvenile xanthogranuloma, and hemophagocytic lymphohistiocytosis. The inherited lysosomal disorders resulting in XG processes include Nieman-Pick, Gaucher, and other lysosomal storage disorders.

CONCLUSION

Radiologists need to be able to recognize features of xanthogranulomatous processes to help facilitate patient management.

Abdominal manifestations of histiocytic disorders in adults: imaging perspective

Histiocytic disorders (HDs) are a diverse group of diseases characterized by pathologic infiltration of normal tissues by cells of the mononuclear phagocyte system. The spectrum of these diseases ranges from treatable infectious diseases to rapidly progressive, life-threatening conditions. Although they are rare and difficult diagnoses, HDs can be diagnosed with the help of clinical and laboratory analyses, imaging features and tissue biopsy. The clinicopathology and imaging spectrum of select entities belonging to this disorder are presented in this review.

So-called Acute Acalculous Cholecystitis in Macrophage Activation Syndrome

Acute acalculous cholecystitis (AAC) is a severe disease seen in critically ill patients, including those with autoimmune diseases. We herein report the case of a 41-year-old female who developed macrophage activation syndrome (MAS) accompanied by a recurrence of Kikuchi disease. Abdominal imaging revealed marked thickening of the gallbladder wall and pericholecystic fluid, typically found in AAC. Treatment with intravenous pulse methylprednisolone induced in a significant improvement in the gallbladder wall, resulting in no need for surgical intervention. We should consider that patients with MAS may therefore sometimes develop AAC and that early immunosuppressive therapy can be effective in AAC cases associated with rheumatic or autoimmune diseases.

Progressive Diffuse Osteonecrosis in a Patient with Secondary Hemophagocytic Lymphohistiocytosis

This is a case report with serial imaging showing progression of diffuse osteonecrosis in a patient after a diagnosis of secondary hemophagocytic lymphohistiocytosis (HLH). While bone marrow involvement in HLH has been long noted at histological evaluation and is itself one of the diagnosis criteria, to the best of our knowledge, there has been no previous publication addressing osseous image findings in a patient with HLH.

More than just Langerhans cell histiocytosis: a radiologic review of histiocytic disorders

Although Langerhans cell histiocytosis (LCH) is a familiar entity to most radiologists and to pediatric radiologists in particular, it is but one of a group of disorders caused by the overproduction of histiocytes, a subtype of white blood cells. Other less familiar diseases in this category are Erdheim-Chester disease (ECD), juvenile xanthogranuloma (JXG), Rosai-Dorfman disease (RDD), and hemophagocytic lymphohistiocytosis (HLH). This review describes the classification system, clinical manifestations, and pathophysiology of each disease, with particular attention to differential radiographic findings, including typical locations of involvement and varying appearances at radiography, computed tomography, magnetic resonance imaging, ultrasonography, and nuclear medicine imaging. Although LCH has a wide variety of manifestations and appearances, classic imaging findings include vertebra plana, skull lesions with a beveled edge, the "floating tooth" sign, bizarre lung cysts, and an absent posterior pituitary bright spot with infundibular thickening. The classic imaging findings of ECD are a perirenal rind of soft tissue and patchy long bone osteosclerosis. RDD has more nonspecific imaging findings, including lymphadenopathy (most commonly cervical) and intracranial lesions. Imaging findings in HLH are broad, with the most common abnormalities being hepatosplenomegaly, cerebral volume loss, and periventricular white matter abnormalities. JXG can manifest at imaging, but radiology does not play a major role in diagnosis. Familiarity with these disorders and their associated imaging findings facilitates correct and timely diagnosis. Imaging also features prominently in the assessment of treatment response.

An uncommon presentation of EBV-driven HLH. Primary or secondary? An ongoing dilemma

Haemophagocytic lymphohistiocytosis (HLH) is a potentially fatal syndrome, mainly characterised by dysregulated immune activation. The syndrome is related to a genetic cause, in the classic primary form, or to identified triggers such as infections, malignancy or rheumatological processes, in the classic secondary form. Epstein-Barr virus (EBV) is the most common agent implicated in hereditary and non-hereditary conditions. We describe a 23-month-old girl who experienced severe clinical deterioration with respiratory distress due a bilateral pleural effusion within the first week of primary EBV infection. Fever, generalised oedema and hepatosplenomegaly, along with a pruritic morbilliform erythematous rash, were the first clinical signs. Respiratory impairment followed with hypoxaemia and the patient was admitted to the intensive care unit for thoracocentesis. Further investigation showed persistent bicytopaenia, hypertriglyceridaemia, hyperferritinaemia and elevated α chain of interleukin-2 receptor (sCD25). Diagnostic criteria for HLH were fulfilled. Therapy was instituted with dexamethasone, ciclosporin A and intravenous immunoglobulin 6 days after admission with progressive clinical recovery.

Acalculous diffuse gallbladder wall thickening in children

PURPOSE

Gallbladder (GB) wall thickening can be found in various conditions unrelated to intrinsic GB disease. We investigated the predisposing etiologies and the outcome of acalculous GB wall thickening in children.

METHODS

We retrospectively analyzed 67 children with acalculous GB wall thickening who had visited our institute from June 2010 to June 2013. GB wall thickening was defined as a GB wall diameter >3.5 mm on abdominal ultrasound examination or computed tomography. Underlying diseases associated with GB wall thickening, treatment, and outcomes were studied.

RESULTS

There were 36 boys and 31 girls (mean age, 8.5±4.8 years [range, 7 months-16 years]). Systemic infection in 24 patients (35.8%), acute hepatitis in 18 (26.9%), systemic disease in 11 (16.4%), hemophagocytic lymphohistiocytosis in 4 (6.0%), acute pancreatitis in 3 (4.5%), and specific liver disease in 3 (4.5%) predisposed patients to GB wall thickening. Systemic infections were caused by bacteria in 10 patients (41.7%), viruses in 5 patients (20.8%), and fungi in 2 patients (8.3%). Systemic diseases observed were systemic lupus erythematosus in 2, drug-induced hypersensitivity in 2, congestive heart failure in 2, renal disorder in 2. Sixty-one patients (91.0%) received symptomatic treatments or treatment for underlying diseases. Five patients (7.5%) died from underlying diseases. Cholecystectomy was performed in 3 patients during treatment of the underlying disease.

CONCLUSION

A wide range of extracholecystic conditions cause diffuse GB wall thickening that resolves spontaneously or with treatment of underlying diseases. Surgical treatments should be avoided if there are no definite clinical manifestations of cholecystitis.

MR findings of fulminent leukoencephalopathy in EBV-associated hemophagocytic syndrome

Various manifestations of brain involvement for patients with virus-associated hemophagocytic syndrome have been reported. Here, we report on the sequential magnetic resonance (MR) findings of acute demyelination of the entire brain with subsequent brain atrophy in a follow-up study of a 25-month- old boy who was admitted with fever and then diagnosed with infectious mononucleosis and EBV-associated hemophagocytic syndrome. We also review other conditions that should be included in the differential diagnosis of this disease.