Pediatric Burkitt's lymphoma and diffuse B-cell lymphoma: are surveillance scans required?

Outcomes in pediatric B-Non-Hodgkin Lymphoma (B NHL) have improved with intensive chemotherapy protocols, with long-term survival now over 80%. However, long-term adverse effects of therapy and poor outcomes for patients who relapse remain challenges. In this study, we aimed to evaluate the potential risks and benefits of routine relapse surveillance imaging after the completion of therapy. We reviewed 44 B NHL patients diagnosed and treated at Texas Children's Cancer Center in the period between 2000 to 2011. All cross-sectional diagnostic imaging examinations performed for disease assessment after completion of chemotherapy were reviewed and cumulative radiation dosage from these examinations and the frequency of relapse detection by these examinations were recorded. Only 3 patients of the 44 relapsed (6.8%), though none of the relapses were initially diagnosed by computed tomography (CT) or fludeoxyglucose positron emission tomography (FDG-PET) scans. Median effective dose of ionizing radiation per patient was 40.3 mSv with an average of 49.1 mSv (range 0-276 mSv). This single-institution study highlights the low relapse rate in pediatric B-NHL with complete response at the end of therapy, the low sensitivity of early detection of relapse with surveillance CT or FDG-PET imaging, and the costs and potential increased risk of secondary malignancies from cumulative radiation exposure from surveillance imaging. We propose that routine surveillance CT or FDG-PET scans for these patients may not be necessary.

Pediatric Hodgkin lymphoma: are we over-scanning our patients?

Despite the favorable outcome of most pediatric patients with Hodgkin lymphoma (HL), there is rising concern about risks of carcinogenesis from both diagnostic and therapeutic radiation exposure for patients treated on study protocols. Although previous studies have investigated radiation exposure during treatment, radiation from post-treatment surveillance imaging may also increase the likelihood of secondary malignancies. All diagnostic imaging examinations involving ionizing radiation exposure performed for surveillance following completion of therapy were recorded for 99 consecutive pediatric patients diagnosed with HL from 2000 to 2010. Cumulative radiation dosage from these examinations and the frequency of relapse detection by these examinations were recorded. In the first 2 years following completion of therapy, patients in remission received a median of 11 examinations (range 0-26). Only 13 of 99 patients relapsed, 11 within 5 months of treatment completion. No relapse was detected by 1- or 2-view chest radiographs (n = 38 and 296, respectively), abdomen/pelvis computed tomography (CT) scans (n = 211), or positron emission tomography (PET) scans alone (n = 11). However, 10/391 (2.6%) of chest CT scans, 4/364 (1.1%) of neck CT scans, and 3/47 (6.4%) of PET/CT scans detected relapsed disease. Thus, only 17 scans (1.3%) detected relapse in a total of 1358 scans. Mean radiation dosages were 31.97 mSv for Stage 1, 37.76 mSv for Stage 2, 48.08 mSv for Stage 3, and 51.35 mSv for Stage 4 HL. Approximately 1% of surveillance imaging examinations identified relapsed disease. Given the very low rate of relapse detection by surveillance imaging stipulated by current protocols for pediatric HL patients, the financial burden of the tests themselves, the high cure rate, and risks of second malignancy from ionizing radiation exposure, modification of the surveillance strategy is recommended.

Neuroimaging in Pediatric Patients with Juvenile Xanthogranuloma of the CNS.

BACKGROUND AND PURPOSE: Juvenile xanthogranuloma is a rare clonal, myeloid, neoplastic disorder. Typically, juvenile xanthogranuloma is a self-limited disorder of infancy, often presenting as a solitary red-brown or yellow skin papule/nodule. A small subset of patients present with extracutaneous, systemic juvenile xanthogranuloma, which may include the CNS. The goal of this retrospective study was to evaluate and categorize the neuroimaging findings in a representative cohort of pediatric patients with CNS juvenile xanthogranuloma. MATERIALS AND METHODS: The brain and/or spine MR imaging data of 14 pediatric patients with pathology-proven juvenile xanthogranuloma were categorized and evaluated for the location; the signal intensity of xanthogranulomas on T1WI, T2WI, DWI, and a matching ADC map for the pattern and degree of contrast enhancement; and the presence of perilesional edema, cysts, or necrosis. RESULTS: Fourteen pediatric patients (8 girls, 6 boys; mean age, 84 months) were included in the study. Patients presented with a wide variety of different symptoms, including headache, seizure, ataxia, strabismus, hearing loss, facial paresis, and diabetes insipidus. Juvenile xanthogranuloma lesions were identified in a number of different sites, including supra- and infratentorial as well as intracranial and spinal leptomeningeal. Five patients were categorized into the neuroradiologic pattern unifocal CNS juvenile xanthogranuloma; 8, into multifocal CNS juvenile xanthogranuloma; and 1, into multifocal CNS juvenile xanthogranuloma with intracranial and spinal leptomeningeal disease. In most cases, xanthogranulomas were small-to-medium intra-axial masses with isointense signal on T1WI (compared with cortical GM), iso- or hyperintense signal on T2WI, had restricted diffusion and perilesional edema. Almost all xanthogranulomas showed avid contrast enhancement. However, we also identified less common patterns with large lesions, nonenhancing lesions, or leptomeningeal disease. Four cases had an additional CT available. On CT, all xanthogranulomas were homogeneously hyperdense (solid component) without evident calcifications. CONCLUSIONS: CNS juvenile xanthogranuloma may demonstrate heterogeneous neuroimaging appearances potentially mimicking other diseases, such as primary brain neoplasms, metastatic disease, lymphoma and leukemia, other histiocytic disorders, infections, or granulomatous diseases.

Expression of oncogenes in human leukemias.

Oncogenes of retroviruses are directly related to cancers in animals; however, finding relevant associations with human cancer has been difficult. Studies reported here were designed to assess the extent of protooncogene transcription in human leukemias as compared to normal cells. Low-stringency hybridization of viral oncogene DNAs to cell messenger RNAs was done to determine whether evolutionarily divergent oncogene sequences were increased in leukemic cells. Several oncogenes hybridized at low levels to normal messenger RNAs. Some oncogene transcripts in fresh leukemic cells of 28 patients were present at higher levels than in normal cells. The oncogenes abl, erb, myc, and ras were expressed in all normals tested and a majority of the leukemic cells. However, fes, fps, and src probes hybridized rarely to transcripts in normal cells although more frequently to messenger RNA from leukemic cells. No oncogenes were expressed in specific patterns by cell types. It is concluded that transformation of human hematopoietic cells involves more than one oncogene and may include sequences unrelated to retroviruses.

Heterogeneity in lineage derivation of Philadelphia-positive acute lymphoblastic leukemia expressing p190BCR-ABL or p210BCR-ABL: determination by analysis of individual colonies with the polymerase chain reaction.

The molecular hallmark of Philadelphia chromosome-positive acute lymphoblastic leukemia (ALL) is the expression of 1 of 2 alternate forms of the aberrant BCR-ABL protein-p210BCR-ABL or p190BCR-ABL. The presence of BCR-ABL message provides a target for analyzing the lineage derivation of this disease. We, therefore, studied myeloid and erythroid progenitor involvement in Philadelphia chromosome-positive ALL. Bone marrow low-density cells from Philadelphia chromosome-positive ALL patients (5 with the p190BCR-ABL and 2 with the p210BCR-ABL anomaly) were cultured in the mixed colony culture assay. cDNA from individually plucked colony-forming unit-granulocyte-macrophage and burst-forming unit-erythroid colonies was then analyzed using the hybridization protection assay in conjunction with the polymerase chain reaction to detect BCR-ABL molecular aberrations. Colony-forming unit-granulocyte-macrophage and burst-forming unit-erythroid colonies from 1 of 5 p190BCR-ABL-positive patients and 1 of 2 p210BCR-ABL-positive patients expressed BCR-ABL transcripts, whereas colony-forming unit-granulocyte-macrophage and burst-forming unit-erythroid colonies from the other patients did not. Our study suggests that the origin of both p190BCR-ABL- and p210BCR-ABL-positive ALL is heterogenous with involvement of either a pluripotent precursor or a lymphoid lineage-committed hematopoietic progenitor.

No involvement of bovine leukemia virus in childhood acute lymphoblastic leukemia and non-Hodgkin's lymphoma.

Bovine leukemia virus (BLV) is the causative agent of enzootic bovine lymphosarcoma. Much speculation continues to be directed at the role of BLV in human leukemia. To test this hypothesis rigorously, a case-control study of childhood acute lymphoblastic leukemia and non-Hodgkin's lymphoma was conducted between December 1983 and February 1986. Cases (less than or equal to 16 years at diagnosis) derived from patients diagnosed at the primary institutions and affiliated hospitals were matched (age, sex, and race) with regional population controls. DNA samples from bone marrow or peripheral blood from 157 cases (131 acute lymphoblastic leukemia, 26 non-Hodgkin's lymphoma) and peripheral blood from 136 controls were analyzed by Southern blot technique, under highly stringent conditions, using cloned BLV DNA as a probe. None of the 157 case or 136 control DNA samples hybridized with the probe. The high statistical power and specificity of this study provide the best evidence to date that genomic integration of BLV is not a factor in childhood acute lymphoblastic leukemia/non-Hodgkin's lymphoma.

Persistence of self-renewing leukemia cell progenitors during remission in children with B-precursor acute lymphoblastic leukemia.

No effective therapy is available for the majority of the 30-40% of children with acute lymphoblastic leukemia (ALL) who relapse. Since the morphologically undetectable, or occult, leukemia cells that persist during remission originate from the clone present at diagnosis, may also have both the capability to sustain the disease and to give rise to relapse, we are evaluating a method of identifying them. We have combined, for the first time, an ALL blast colony assay (BCA) and the polymerase chain reaction (PCR) to isolate residual leukemia cells in remission bone marrow aspirate specimens from eight patients with B-precursor ALL during early continuation therapy. We found colony-forming leukemia cells with in vitro self-renewal capability that survived chemotherapy for 15 months after diagnosis in all sequential specimens from these patients. To verify the leukemic nature of these cells their DNA was amplified by PCR and the product directly sequenced. In every case, the VHDJH sequence observed at diagnosis was found. None of the patients relapsed during this early phase of their treatment, consistent with the observation that patients with B-precursor ALL experience recurrence late in their course. Since it is possible that some of these persistent leukemia cells belong to the leukemia progenitor cell population that sustains the disease, the study of them could provide the means to determine the mechanisms of relapse.

DNA polymorphisms and mutations of the tumor necrosis factor-alpha (TNF-alpha) promoter in Langerhans cell histiocytosis (LCH).

Langerhans cell histiocytosis (LCH) is a clonal proliferation of dendritic histiocytes expressing elevated levels of tumor necrosis factor-alpha (TNF-alpha), interferon-gamma (IFN-gamma) granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-1 (IL-1), and leukemia inhibitory factor (LIF). The cause of the increased cytokine levels is unknown, but DNA sequence changes in promoters could alter expression. The TNF-alpha and IFN-gamma promoter DNA sequences of 12 LCH patients were studied and compared with normal individuals by dideoxy fingerprinting and DNA sequencing. Functional consequences of polymorphic or mutated sequences were assessed by cloning altered and control promoter sequences into a luciferase reporter gene vector. Electrophoretic mobility shifts (EMSA) after binding of nuclear extracts from a macrophage cell line (U-937) by mutated promoters were compared with controls. Five of 12 LCH patients had alterations in the TNF-alpha promoter DNA sequence. None were found in the IFN-gamma gene promoter. Of the 5 with TNF-alpha DNA alterations, 2 were at position -308, which has been described as a G-A polymorphism associated with upregulation of TNF-alpha in some patients with infections or immune-mediated diseases. The polymorphism at -308 but not the other TNF-alpha promoter mutations caused a 3-fold to 7-fold increased production of the luciferase reporter gene. EMSA showed that the -308 mutant promoters bound fewer nuclear proteins than normals. Polymorphisms of the TNF-alpha promoter in LCH patients could increase the production of that cytokine.

Epstein-Barr virus--determined clonality in posttransplant lymphoproliferative disease.

Analysis of the genomic termini of Epstein-Barr virus can provide valuable insight into the cofactor role of EBV in the development of B cell lymphomas and lymphoproliferative disease. We report EBV genomic findings in pathologic specimens from 10 patients who developed lymphoma or lymphoproliferative disease after renal or bone marrow transplantation. Endonuclease restriction patterns of EBV genomic termini are highly variable in size in both the episomal and linear configuration. This variability in fragment size permits direct assessment of tissue clonality in EBV-infected material. Hybridization with terminus-specific probes also reveals configuration of viral genome (circular and latent vs. linear and replicative). Nine of 10 patients had tumors with mono- or biclonal episomal markers, and 4 of 10 had evidence of linear or replicative virus. Analyses of virally determined markers were compared to immunoglobulin gene rearrangement studies, histologic immunophenotyping, cytogenetics, and clinical outcome. These 10 cases represent a spectrum of lymphoproliferative disorders ranging from benign polyclonal to malignant monoclonal disease. The molecular data lend credence to two important aspects of viral pathogenesis: (1) the finding of a homogeneous episomal population in the monoclonal tumors suggests that EBV infection is an early event in tumorigenesis that occurs before clonal expansion; and (2) therapeutic efficacy of acyclovir has been shown only in presence of polyclonal disease but may impact on intermediate stages where linear replicative virus can be found. Finally, the various assessments of tumor clonality were compared, and although heterogeneity was seen among patients and among diagnostic methods, analyses at the molecular level using virus and immunoglobulin gene specific probes were concurrent and provide the more sensitive means for detection of clonality.

Physiology and pathophysiology of dendritic cells.

Dendritic cells are antigen-presenting cells derived from the hematopoietic stem cell. The dendritic cell family includes Langerhans' cells (CD1a-positive dendritic cells of the skin), and antigen-presenting cells that are found in the lymphoreticular system and throughout the organ parenchyme. Dendritic cells play a key role in both the primary and secondary immune responses. Several studies indicate that these cells participate in antitumor immunity, tumor surveillance, graft-versus-host disease, and in the pathogenesis of clinical syndromes of unknown origin or those induced by viruses, such as the human immunodeficiency virus. Different disorders are characterized by an abnormal proliferation and accumulation of dendritic cells; for example, the Langerhans' histiocytes, which accumulate in Langerhans' cell histiocytosis. In this review the immunophenotypic, morphological, and functional characteristics of the dendritic cell family is described. The clinical and laboratory studies suggesting a unique role for these cells in various syndromes and diseases are reviewed. The Langerhans' cell histiocytoses and the malignant disorders associated with transformation of cells belonging to the dendritic cell family, are discussed.

Aseptic meningitis in a child after systemic treatment with high dose cytarabine.

Cytarabine was temporally associated with aseptic meningitis syndrome in an 8-year-old Hispanic girl being treated for acute lymphoblastic leukemia.

Acute lymphoblastic leukemia-hand mirror variant. Analysis for endogenous retroviral antibodies in bone marrow plasma.

Two unusual cases of acute lymphoblastic leukemia-hand mirror variant (ALL-HMV) are presented. One patient demonstrated a mixed immunophenotype with HLA-DR, My7, transferrin receptor surface markers, and terminal deoxynucleotidyl transferase positivity. To the authors' knowledge, this is the first ALL-HMV reported with myeloid antigen. The patient died during induction and did not demonstrate the indolent course noted in the female subgroup with this disorder. The second case initially was not an ALL-HMV but presented as a non-T non-B ALL, and the patient had a relapse six years later with numerous hand mirror cells (HMCs). In the authors' experience, this is the first case of ALL that presented as a non-HMC and relapsed as an ALL-HMV. The patient's immunophenotype revealed he was HLA-DR, transferrin receptor, and TdT positive. Both patients' leukemic cells showed a diffuse granular periodic acid-Schiff on a clear background and acid phosphatase-positive pattern. Immunogenetics revealed a clonal rearrangement of one of the two Ig heavy chain loci in the one patient evaluated. Western blot analysis of the bone marrow plasma of both patients with ALL-HMV showed an increase of cross-reactive IgG to the envelope gp70 and IgM against the core p30 proteins of the baboon endogenous virus (BaEV) and simian sarcoma-associated virus (SSAV). Furthermore, their bone marrow plasma demonstrated IgM antibodies to the gp70 that were not present in any of the other non-hand mirror leukemic patients or the normal controls. These findings strengthen the concept that HMCs in ALL are formed in relation to an immunologic response to increased proteins related to BaEV and/or SSAV.

The spectrum of mucosa-associated lymphoid tissue lesions in pediatric patients infected with HIV: A clinicopathologic study of six cases.

Mucosa-associated lymphoid tissue (MALT) lesions in nonimmunocompromised individuals include reactive lymphoid proliferations and both low- and high-grade lymphoid neoplasms. These lesions occur at extranodal mucosal sites, such as the gastrointestinal tract, bronchus, salivary gland, and other locations. The spectrum of MALT lesions in children with HIV infection had not been previously described. In this study, six cases that demonstrated the spectrum of MALT lesions in pediatric patients, aged 28 months to 23 years, who had HIV infection were described. Half the patients acquired the infection perinatally, and half acquired it by transfusion. Mucosal sites of involvement included the salivary gland (4 patients), bronchiolar mucosa (2 patients), and oropharyngeal mucosa (1 patient). One patient had lesions in lung and oropharynx sequentially; all others had involvement of solitary sites. The histologic diagnoses included myoepithelial sialadenitis (MESA), MESA with low-grade MALT lymphoma, typical low-grade MALT lymphoma, diffuse large cell lymphoma (DLCL), and atypical pulmonary lymphoid hyperplasia and lymphoid interstitial pneumonitis complex. The two cases of high-grade DLCL were confined to mucosal sites (tonsil and parotid); in one of these patients, a previous biopsy specimen showed a MALT lesion with low-grade features. In two cases, quantitation of the Epstein-Barr virus (EBV) genome by the polymerase chain reaction showed a very high copy number in peripheral blood mononuclear cells but a low copy number in the MALT lesion, which suggested that MALT lesions may not be directly associated with EBV infection. Two patients who had high-grade tumors (DLCL) were successfully treated with chemotherapy and radiation therapy. The remaining patients, all of whom had low-grade MALT lesions, received either corticosteroids or alpha-interferon or no specific therapy; in all patients, the lesions followed an indolent clinical course. Clinicians and pathologists should be alert to the possibility that MALT lesions, including MALT lymphomas, may be present in children who have AIDS.

An update on clonality, cytokines, and viral etiology in Langerhans cell histiocytosis.

Many etiologies have been proposed for Langerhans cell histiocytosis (LCH). Recent scientific studies have clearly provided new insights into the etiology and pathogenesis of the disease. The possible role of viruses has not been completely negated, but no viral genomes have been consistently detected in LCH lesions. Other studies do not indicate that LCH arises from a primary defect in the immune system, although altered immune responses and immune dysfunction may play a role in the pathophysiology of the disease. Definitive results have been gained from molecular studies of clonality, however. These have definitively established that LCH is a clonal histiocytic disease rather than a reactive polyclonal disorder.

Cancers in children with HIV infection.

Malignancies in children with HIV infection have not been as frequent as expected, but they still constitute a fertile area for clinical and basic research. Non-Hodgkin's lymphomas are the most frequent malignancies of children with AIDS and are curable diseases with standard chemotherapy. Leiomyomas and leiomyosarcomas have become the second leading cancer of children with HIV infection and are clearly associated with EBV infection. Treatment for these lesions has not been as successful as that for lymphomas. Other infrequent atypical lymphoproliferative lesions of these patients can often be categorized in the MALT group. Some of these are low-grade lymphomas, whereas others can progress to high grade. The diagnosis of Kaposi's sarcoma in children with AIDS should be carefully reviewed by pathologists experienced with these cases. The diagnosis of KS in children must be made with special care, because some other lesions of HIV-infected children (such as prominent vascularity in lymph nodes) can be confused with KS. Other tumors of these patients are rare and probably are no more frequent than would be expected in the normal population. Because malignancies in children with AIDS are rare, it is important that each one be studied completely with regard to type and incidence, risk factors, and biologic features. To this end, the Pediatric Oncology Group (POG) has established a national registry and treatment protocols. Patient information as well as fresh, frozen, and fixed specimen studies are coordinated through the POG Statistical Office in Gainesville, Florida (telephone, 904-392-5198; FAX, 904-392-8162). The collaborative efforts of all physicians treating children with AIDS and malignancies will be needed to advance our knowledge and efficacy in treating these diseases.

Benign and malignant smooth muscle tumors containing Epstein-Barr virus in children with AIDS.

Smooth muscle tumors (leiomyosarcomas) are the second most prevalent malignancy of children with the acquired immunodeficiency syndrome (AIDS). We have investigated the tumors, plasma, and peripheral white blood cells of eight children with AIDS with smooth muscle tumors for evidence of tumor association with human immunodeficiency virus (HIV) and Epstein-Barr virus (EBV). Very low levels of HIV were found in the tumors of the AIDS patients, probably resulting from blood-borne carriage of virus. These smooth muscle tumors had very high quantities of EBV in all the tumor cells by in situ hybridization, with an average of 4.5 EBV genomes per cell by quantitative polymerase chain reaction amplification. Increased amounts of EBV were found in the peripheral blood cells of two AIDS patients before the time of tumor diagnosis. EBV clonality studies demonstrated different monoclonal EBV infection of two separate colonic tumors from one patient, and dual or mixed monoclonal EBV infection in another patient. The muscle cells of leiomyomas and leiomyosarcomas of patients with AIDS demonstrated prominent staining with antibodies to the EBV receptor. The uniform distribution and striking amount of EBV in the tumor cells demonstrates that EBV is capable of infecting smooth muscle cells and that these cells support EBV replication. Clonal EBV proliferation suggests that EBV infection occurs at an early stage of tumor development. These findings indicate that EBV has a causal role in the oncogenesis of leiomyosarcomas of patients with AIDS.

Epstein-Barr virus and HIV-AIDS-associated diseases.

Among the secondary problems of patients with the human immune deficiency virus (HIV) infection are lymphadenopathy, atypical lymphoproliferations, and malignant transformations of lymphoid, muscle, and epithelial cells caused by infection with Epstein-Barr virus (EBV). The lymphoproliferative diseases associated with EBV infection include lymphocytic interstitial pneumonitis, lymphomas of primary and extra-nodal sites, such as the central nervous system (CNS), and mucosa-associated lymphoid tissue (MALT). EBV infection causes these diseases through a combination of mechanisms including use of virus-encoded transforming genes, stimulation of diverse cytokines, and interaction with receptors for the tumor necrosis factor (TNF) family of cytokines.

Role of the surgeon in the treatment of children's cancer.

The management of children's tumors has changed significantly in the past several years. New techniques and combined surgical, chemotherapeutic, and radiation approaches are responsible for improved survival in most instances. Cooperation of the surgeon with the specialists in separate disciplines is imperative to continued advancements in neoplastic disease of childhood.

Diverse hematologic effects of parvovirus B19 infection.

Human parvovirus B19 is linked with a broadening spectrum of hematologic disorders, including aplastic crises in the context of hemolytic anemias, neutropenia, thrombocytopenia, and hemophagocytic syndromes. Children with any of these cytopenias should be screened for the presence of B19 because treatment with intravenous gamma globulin may provide resolution of abnormal blood counts if other therapeutic options, such as transfusion, are not adequate or desired.

Chronic, episodic thrombocytopenia. A case report with long-term observation.

A male patient with chronic idiopathic thrombocytopenic purpura (ITP) did not fit into any of the known risk groups for chronic ITP. He was unique in that he manifested a cyclic increase of platelet counts each winter followed by a nadir in the summer, without having other hematologic abnormalities.