Central nervous system imaging in childhood leukaemia

Cranial MRI in Childhood Acute Leukemia during Treatment and Follow-Up Including the Impact of Intrathecal MTX-A Single-Center Study and Review of the Literature

Due to high survival rates, long-term sequelae, especially neurotoxicity, need to be considered in childhood acute leukemias. In this retrospective analysis of morphologic changes of the brain in children treated for acute leukemias, we included 94 patients (77 ALL, 17 AML; 51 male, 43 female; median age: 5 years) from a single center. We analyzed 170 cranial MRI scans (T2, FLAIR axial) for morphologic alterations of the brain and variations of the ventricular width (GDAH). In addition, the corresponding literature was reviewed. More than 50% of all patients showed cerebral pathomorphologies (CP). They were seen more often in children with ALL (55.8%), ≤ 6 years of age (60.8%), in relapse (58.8%) or after CNS irradiation (75.0%) and included white matter changes, brain atrophy, sinus vein thrombosis and ischemic events. GDAH significantly enlarged mainly in children up to 6 years, with relapse, high-risk leukemias or ALL patients. However, GDAH can normalize again. The number of intrathecal Methotrexate applications (≤12 vs. >12) showed no correlation to morphologic alterations besides a significant increase in GDAH (−0.3 vs. 0.9 mm) between the first and last follow-up MRI in ALL patients receiving >12 ith. MTX applications. The role of ith. MTX on CP needs to be further investigated and correlated to the neurocognitive outcome of children with acute leukemias.

Juvenile myelomonocytic leukemia presenting in an infant with a subdural hematoma

BACKGROUND

Juvenile myelomonocytic leukemia (JMML) is a rare childhood hematopoietic disorder typically presenting with hepatosplenomegaly, lymphadenopathy, pallor, fever, and cutaneous findings. The authors report the first case, to our knowledge, of JMML presenting in a pediatric patient with a subdural hematoma.

CASE DESCRIPTION

A 7-month old male with recurrent respiratory infections and a low-grade fever presented with a full fontanelle and an increasing head circumference and was found to have chronic bilateral subdural collections. Abusive head trauma, infectious, and coagulopathy workups were unremarkable, and the patient underwent bilateral burr holes for evacuation of the subdural collections. The postoperative course was complicated by the development of thrombocytopenia, anemia, and an acute subdural hemorrhage which required evacuation. Cytologic analysis of the subdural fluid demonstrated atypical cells, which prompted flow cytometric analysis, a bone marrow biopsy, and ultimately a diagnosis of JMML. Following chemotherapy, the patient's counts improved, and he subsequently underwent a hematopoietic stem cell transplant.

CONCLUSION

Subdural collections may rarely represent the first presenting sign of hematologic malignancies. In patients with a history of recurrent infections and a negative workup for abusive head trauma, clinicians should include neoplastic etiologies in the differential for chronic subdural collections and have a low threshold for fluid analysis.

A narrative review of central nervous system involvement in acute leukemias

Acute leukemias (both myeloid and lymphoblastic) are a group of diseases for which each year more successful therapies are implemented. However, in a subset of cases the overall survival (OS) is still exceptionally low due to the infiltration of leukemic cells in the central nervous system (CNS) and the subsequent formation of brain tumors. The CNS involvement is more common in acute lymphocytic leukemia (ALL), than in adult acute myeloid leukemia (AML), although the rates for the second case might be underestimated. The main reasons for CNS invasion are related to the expression of specific adhesion molecules (VLA-4, ICAM-1, VCAM, L-selectin, PECAM-1, CD18, LFA-1, CD58, CD44, CXCL12) by a subpopulation of leukemic cells, called “sticky cells” which have the ability to interact and adhere to endothelial cells. Moreover, the microenvironment becomes hypoxic and together with secretion of VEGF-A by ALL or AML cells the permeability of vasculature in the bone marrow increases, coupled with the disruption of blood brain barrier. There is a single subpopulation of leukemia cells, called leukemia stem cells (LSCs) that is able to resist in the new microenvironment due to its high adaptability. The LCSs enter into the arachnoid, migrate, and intensively proliferate in cerebrospinal fluid (CSF) and consequently infiltrate perivascular spaces and brain parenchyma. Moreover, the CNS is an immune privileged site that also protects leukemic cells from chemotherapy. CD56/NCAM is the most important surface molecule often overexpressed by leukemic stem cells that offers them the ability to infiltrate in the CNS. Although asymptomatic or with unspecific symptoms, CNS leukemia should be assessed in both AML/ALL patients, through a combination of flow cytometry and cytological analysis of CSF. Intrathecal therapy (ITT) is a preventive measure for CNS involvement in AML and ALL, still much research is needed in finding the appropriate target that would dramatically lower CNS involvement in acute leukemia.

Role of magnetic resonance imaging in characterization of central nervous system lesions in pediatric patients with leukemia and post-treatment complications

Background

Leukemia is one of the most common fatal diseases in pediatric oncology. Recently, advances in drug therapy have improved the prognosis of acute leukemia with event-free survival of up to 60%; however, complications and adverse effects of the disease and anti-leukemic treatment have also increased. The CNS complications of leukemia can be classified into those that developed directly or indirectly from the underlying leukemic process and those that can be related to antileukemic therapy. MRI had improved early detection of CNS complications and proper management. The study aims to characterize the MRI findings caused by the leukemic involvement of CNS structures and treatment-associated CNS complications and assess its value in early management and avoidance of long-term side effects.

Results

The patient’s age ranged from 2 to 18 years with different types of leukemia classified regarding the time of presentation as pretreatment, during treatment phases, and post-treatment. Different MRI abnormalities were recorded and clinically correlated.

Conclusion

The neurological complications of leukemia have common presenting symptoms but varying imaging abnormalities. To reach the correct diagnosis, the presenting signs, symptoms, and laboratory data must be considered along with the radiologic findings. A diagnostic algorithm using conventional, post-contrast MRI, MR venography, along with diffusion-weighted MRI was of great value in early detection and differentiation of different CNS lesions detected in pediatric patients with leukemia and post-treatment CNS complications.

Role of neuroimaging in children with acute lymphoblastic leukemia and central nervous system involvement at diagnosis

BACKGROUND

Each year approximately 200 children and adolescents are diagnosed with acute lymphoblastic leukemia (ALL) in the five Nordic countries, and 3% of these have central nervous system (CNS) involvement confirmed by leukemic cells in the cerebrospinal fluid (CSF) or neurological symptoms. We sought to determine the significance of neuraxis imaging in such patients.

PROCEDURE

Magnetic resonance images of children aged 1-17.9 with CNS leukemia at diagnosis of ALL were centrally reviewed and clinical data were retrieved from the medical records and the Nordic leukemia registry. Patients were diagnosed in the period 2000-2012 in Sweden, Finland, or Denmark.

RESULTS

The cohort comprised 1,877 patients, and 66 (3.5%) had CNS involvement. Forty-five percent (30/66) had CNS related symptoms. Symptoms included vomiting, facial palsy, headache, visual symptoms, and impaired hearing. CNS imaging was performed in 32 of 66 children (48%), and confirmed CNS involvement in 6 of 21 patients with symptoms (29%) and 5 of 11 (45%) without (P = 0.44). There was no difference in the overall survival between CNS-positive patients with and without signs of leukemic involvement by imaging (P = 0.53).

CONCLUSIONS

Radiological imaging of asymptomatic children with CNS leukemia at diagnosis lacks clinical importance, but may be useful in patients with cranial nerve symptoms and negative CSF, as well as for follow-up. Imaging of symptomatic patients is warranted in order to exclude other causes underlying the symptoms.

[Brain injury after induction chemotherapy in children with acute lymphoblastic leukemia]

OBJECTIVE

To investigate the changes in brain injury after the induction chemotherapy in children with acute lymphoblastic leukemia (ALL) by cranial MRI.

METHODS

The clinical data and cranial MRI results of 62 children with ALL who were hospitalized from March 2014 to June 2015 were analyzed retrospectively.

RESULTS

Before chemotherapy, MRI showed bone marrow infiltration of the skull in 33 patients (53%); the children with WBC<20×10(9)/Lhad a significantly lower incidence rate of bone marrow infiltration of the skull than those with WBC≥20×10(9)/L (16 patients/42% vs 17 patients/71%; P<0.05), and the high-risk group had a significantly higher incidence rate of bone marrow infiltration of the skull than the non-high-risk group (71% vs 44%; P<0.05). Before chemotherapy, there were 4 cases (7%) of brain atrophy, and 2 cases (3%) of abnormal signals in the sensory conduction bundle. MRI reexamination in 28 patients after 3 months of chemotherapy showed 3 new cases (11%) of brain atrophy and 1 aggravated case of brain atrophy.

CONCLUSIONS

The children with ALL have bone marrow infiltration of the skull, brain atrophy, and abnormal signals in the sensory conduction bundle before chemotherapy, especially bone marrow infiltration of the skull, and some changes in brain injury disappear after treatment.

[Brain injury after induction chemotherapy in children with acute lymphoblastic leukemia]

OBJECTIVE

To investigate the changes in brain injury after the induction chemotherapy in children with acute lymphoblastic leukemia (ALL) by cranial MRI.

METHODS

The clinical data and cranial MRI results of 62 children with ALL who were hospitalized from March 2014 to June 2015 were analyzed retrospectively.

RESULTS

Before chemotherapy, MRI showed bone marrow infiltration of the skull in 33 patients (53%); the children with WBC<20×10(9)/Lhad a significantly lower incidence rate of bone marrow infiltration of the skull than those with WBC≥20×10(9)/L (16 patients/42% vs 17 patients/71%; P<0.05), and the high-risk group had a significantly higher incidence rate of bone marrow infiltration of the skull than the non-high-risk group (71% vs 44%; P<0.05). Before chemotherapy, there were 4 cases (7%) of brain atrophy, and 2 cases (3%) of abnormal signals in the sensory conduction bundle. MRI reexamination in 28 patients after 3 months of chemotherapy showed 3 new cases (11%) of brain atrophy and 1 aggravated case of brain atrophy.

CONCLUSIONS

The children with ALL have bone marrow infiltration of the skull, brain atrophy, and abnormal signals in the sensory conduction bundle before chemotherapy, especially bone marrow infiltration of the skull, and some changes in brain injury disappear after treatment.

Evaluation of Pre-Hematopoietic Cell Transplantation (HCT) Brain MRI and Neurologic Complications of Pediatric Patients Undergoing HCT for Hematologic Malignancies

Adverse neurologic complications (NC) occur commonly in pediatric patients with hematologic malignancies both pre- and post-allogeneic hematopoietic cell transplant (HCT). Given this known risk, we previously obtained pre-HCT brain magnetic resonance imaging (MRI) to document baseline abnormalities but utility of this and findings are not well described. This study aimed to ( a) determine the prevalence and risk factors for abnormal brain MRI and ( b) determine prevalence and risk factors for development of new NC during and 2 years post-HCT. Retrospective chart review included 102 patients with hematologic malignancies who underwent allogeneic HCT between 2000 and 2009 at University of California San Francisco (UCSF) Children's Hospital and included standard HCT data, brain MRI reports, and NC and symptoms pre- and post-HCT. Forty-three percent of patients had abnormal findings on pre-MRI, most commonly nonspecific white matter changes. Neurologic symptoms pre-HCT was the only significant risk factor for abnormal MRI. Eleven patients (11%) developed post-HCT NC. Non-Caucasian race was the only significant risk factor for new NC. Although abnormal pre-HCT brain MRI is common, these findings are not predictive of subsequent NC post-HCT. Therefore routine surveillance may not be informative for that purpose, particularly when general anesthesia is required, which can have detrimental neurocognitive effects. Etiology of NC in pediatric HCT is likely multifactorial and may include genetic and ethnic predispositions.

CNS and spinal tumors

Primary CNS tumors consist of a diverse group of neoplasms originating from various cell types in the CNS. Brain tumors are the most common solid malignancy in children under the age of 15 years and the second leading cause of cancer death after leukemia. The most common brain neoplasms in children differ consistently from those in older age groups. Pediatric brain tumors demonstrate distinct patterns of occurrence and biologic behavior according to sex, age, and race. This chapter highlights the imaging features of the most common tumors that affect the child's CNS (brain and spinal cord).

Retrovirus-transformed erythroleukemia cells induce central nervous system failure in a new syngeneic mouse model of meningeal leukemia

Lack of suitable mouse models for central nervous system (CNS)-associated leukemias has hindered mechanism-guided development of therapeutics. By transplanting retrovirus-transformed mouse erythroleukemia cells into syngeneic mice, we developed a new animal model of meningeal leukemia associated with rapid paralysis. Necropsy revealed massive proliferation of the leukemic cells in the bone marrow (BM) followed by pathological angiogenesis and invasion of the leukemic cells into the meninges of the CNS. Further analysis demonstrated that the erythroleukemia cells secreted high levels of VEGF and preferentially adhered in vitro to fibronectin. This unique animal model for meningeal leukemia should facilitate studies of engraftment and proliferation of leukemic cells in the BM and their invasion of the CNS as well as pre-clinical evaluation of experimental therapeutics for CNS-associated leukemias.

Working memory in survivors of childhood acute lymphocytic leukemia: functional neuroimaging analyses

BACKGROUND

Research on the physical and psychological late effects of treatment of childhood cancer has led to the identification of significant long-term neurocognitive deficits experienced by some survivors, particularly in the areas of memory and executive functioning. Despite indications of deficits based on cognitive assessment, the identification of specific mechanisms of neurocognitive deficits using neuroimaging techniques has yet to be adequately considered.

PROCEDURE

This study used functional neuroimaging techniques to examine working memory and executive functioning deficits of survivors of childhood acute lymphocytic leukemia (ALL), as compared to age- and gender-matched healthy controls.

RESULTS

There was a trend for ALL survivors to perform more poorly on a working memory task in terms of overall accuracy. Additionally, survivors displayed significantly greater activation in areas underlying working memory (dorsolateral and ventrolateral prefrontal cortex) and error monitoring (dorsal and ventral anterior cingulate cortex).

CONCLUSIONS

These results support the theory of compensatory activation in necessary brain regions in order to complete tasks in pediatric ALL survivors, similar to that observed in multiple sclerosis patients. Concurrent examination of testing and brain imaging enables the connection of behavioral observations with underlying neurological characteristics of deficits in survivors and may help provide insight into mechanisms through which deficits appear.

Tumefactive intracranial presentation of precursor B-cell acute lymphoblastic leukemia

In children, leukemia is the most common malignancy, and approximately 75% of leukemias are acute lymphoblastic leukemia (ALL). Central nervous system leukemia is found at diagnosis in fewer than 5% of children with ALL. Leukemic intracranial masses have been described with acute myeloid leukemia, but ALL presenting as a mass lesion is rare. We describe a unique case of an intracranial confirmed precursor B cell (pre-B) ALL mass in a 13-year-old girl that was diagnosed by brain CT, MRI and cerebral angiography, and confirmed by biopsy. This report details pertinent history and distinguishing imaging features of an intracranial ALL tumefaction.

CNS complications in children receiving chemotherapy or hematopoietic stem cell transplantation: retrospective analysis and clinical study of survivors

BACKGROUND

Clinical studies analyzing CNS complications in pediatric oncology systematically are rare.

PROCEDURE

In a single center retrospective analysis, CNS complications in 950 subsequent pediatric patients treated between 1992 and 2004 by chemotherapy or hematopoietic stem cell transplantation (HSCT) were studied. Forty-six patients had pre-existing CNS diseases and were excluded. Out of the 904 remaining, 76 (8.4%) had 82 CNS complications.

RESULTS

The most common manifestations were seizures (in 50.6% of the CNS episodes), altered states of consciousness, and motor deficits (in 47.5% of the episodes each). CNS complications were caused by infections (26.8%), toxicity (25.6%), neoplasma (13.4%), vascular (10.9%), and metabolic disturbances (8.5%). In 14.6%, the mechanism remained unclear. Patients (23.7%) died from the CNS event. Neoplastic disorders had the worst (50%) while metabolic the best (0% mortality) prognosis. Imaging techniques were the most effective diagnostic measures, followed by laboratory analysis, clinical examination, and CSF analysis. A neuro-psychological (CBCL, CFT-1/-20-testing) examination could be done in 21 of 32 long-term survivors. Seven had a major, 3 minor neurological impairment, 11 were normal in all tests.

CONCLUSIONS

These data show that there is not one typical CNS complication, but a wide variety. There is no close connection between either underlying disease or symptoms and cause of the complication. Prognosis is variable. About two thirds of the long-term survivors could lead a normal life.

[Imaging of spinal tumors]

Spinal tumors are often categorized into extradural, intradural extramedullary, or intramedullary. Although this classification represents somewhat of an overgeneralization as a lesion may reside in two compartments, it still helps to characterize spinal tumors. In the intradural, extramedullary space, primary tumors, such as neurofibroma and meningioma, are relatively common. Secondary tumors or leptomeningeal enhancement also occur. In the intramedullary space, primary tumors are far more common than secondary tumors or metastases.

Complications of lumbar puncture in a child treated for leukaemia

Lumbar puncture may lead to neurological complications. These include intracranial hypotension, cervical epidural haematomas, and cranial and lumbar subdural haematomas. MRI is the modality of choice to diagnose these complications. This report documents MRI findings of such complications in a child treated for leukaemia.