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.

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.

Expression profiling using human tissues in combination with RNA amplification and microarray analysis: assessment of Langerhans cell histiocytosis

Advances in molecular genetics have led to sequencing of the human genome, and expression data is becoming available for many diverse tissues throughout the body, allowing for exciting hypothesis testing of critical concepts such as development, differentiation, homeostasis, and ultimately, disease pathogenesis. At present, an optimal methodology to assess gene expression is to evaluate single cells, either identified physiologically in living preparations, or by immunocytochemical or histochemical procedures in fixed cells in vitro or in vivo. Unfortunately, the quantity of RNA harvested from a single cell is not sufficient for standard RNA extraction methods. Therefore, exponential polymerase-chain reaction (PCR) based analyses, and linear RNA amplification including amplified antisense (aRNA) RNA amplification and a newly developed terminal continuation (TC) RNA amplification methodology have been used in combination with microdissection procedures such as laser capture microdissection (LCM) to enable the use of microarray platforms within individual populations of cells obtained from a variety of human tissue sources such as biopsy-derived samples {including Langerhans cell histiocytosis (LCH)} as well as postmortem brain samples for high throughput expression profiling and related downstream genetic analyses.

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.

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.

Evaluation of human herpesvirus type 8 infection in childhood langerhans cell histiocytosis

The etiology of Langerhans cell histiocytosis (LCH) is unknown. Viral causes, including human herpesvirus type 6 (HHV6), have been suggested but remain unproved. The recently discovered human herpesvirus type 8 (HHV8), the cause of Kaposi's sarcoma, infects dendritic cells in the bone marrow associated with multiple myeloma. Evidence for an association of HHV8 infection with LCH in children was studied by two approaches: indirectly by HHV8-specific serologic assays and directly by detection of HHV8 sequences using polymerase chain reaction in affected bone marrow samples. Using three different assays specific for HHV8 antibodies, 3 of 10 (30%) children with LCH had detectable HHV8 antibodies, which was not different from the prevalence of 5 of 30 (17%) in healthy controls of similar age (P = 0.65). Of bone marrow samples from three additional children with LCH, all had amplifiable DNA but were negative for HHV8 sequences. These studies of a small number of patients do not demonstrate an increased prevalence of HHV8 infection in children with LCH, and they do not suggest a causal role for HHV8 in the etiology of LCH.

Molecular and virologic characteristics of lymphoid malignancies in children with AIDS

PURPOSE

To characterize AIDS-associated lymphoid malignancies in children.

PATIENTS AND METHODS

We studied lymphomas and B-cell leukemias from 25 children with AIDS for immunoglobulin heavy chain gene clonality, c-myc oncogene abnormalities, and presence of HIV and Epstein-Barr virus.

RESULTS

Monoclonal immunoglobulin gene rearrangements were identified in 22 of 23 cases tested, the single exception being one of mucosa-associated lymphoid tissue. Immunoglobulin gene/c-myc translocations were found in 3 of 4 cases of B (surface immunoglobulin-positive)-acute lymphoblastic leukemia, 8 of 11 small noncleaved cell lymphomas, and 1 of 5 large cell lymphomas. Mutations of c-myc were found in 2 of 13 small noncleaved cell lymphomas, 1 of 2 Epstein-Barr virus-positive mucosa-associated lymphoid tissue neoplasms, and 1 of 4 Epstein-Barr virus-negative B-acute lymphoblastic leukemia. Six small noncleaved cell lymphomas, both mucosa-associated lymphoid tissue neoplasms and one of large cell lymphoma had high levels of Epstein-Barr virus in tumor tissue. Hodgkin's disease tissue and B-acute lymphoblastic leukemia tumors were negative for EBV. Proviral HIV-1 was not detected in any tumor.

CONCLUSIONS

AIDS-associated lymphoid malignancies in children appear to have a different distribution of histologic subtypes than adult HIV-infected individuals, fewer large cell lymphomas occur in children. The small noncleaved cell lymphomas exhibit a lower frequency as well as different locations of c-myc mutations than AIDS-associated small noncleaved cell lymphomas in adults.

Treatment of pediatric B-cell non-Hodgkin's lymphomas at the Motol Hospital in Prague, Czech Republic: results based on the NHL BFM 90 protocols

Malignant non-Hodgkin's lymphomas (NHL) of childhood and adolescence are a heterogeneous group of diseases originating from the lymphoid cells. Unlike adults with non-Hodgkin's lymphoma, children typically have extranodal disseminated disease of high grade (Burkitt's lymphoma, large cell lymphoma, or lymphoblastic lymphoma). This study was conducted to determine the feasibility of treating children in the Czech Republic with B-cell non-Hodgkin's lymphomas according to very intensive protocols based on the German Berlin Frankfurt Munster (BFM) NHL 90 study. Treatments are divided in the BFM studies according to "B" and "non-B" immunophenotypes. The authors report only those treated according to the BFM B-cell protocol. From 1991 through 1997 eighty-two patients less than 18 years with NHL were admitted to the department. Seventy-three of them were classified as B-cell lymphoma and 54 were thus eligible for the BFM B-cell treatment. The entire group consisted of 38 males and 16 females (ratio 2.38). Median age was 11.6 years. Twelve had stage I disease, 3 stage II, 30 stage III, and 9 stage IV lymphoma. There were 21 patients with Burkitt's lymphoma, 29 with large cell lymphoma, of which 5 were patients with MALT lymphoma. In 3 cases B-cell NHL was not further classified and one child had a mediastinal B lymphoma. Patients were further stratified according to clinical stage and lactate dehydrogenase (LDH) level. Therapy consisted of a prephase and short (2, 4, or 6 courses), intensive 5-day therapy with 6 drugs. The probability of event-free survival (pEFS) for the entire group was 74% and overall survival at 5 years was 80%. There was a significantly better outcome for children classified as stage I. No difference was observed between the EFS of stage III and IV patients. Four patients died from treatment-related complications in complete remission. Treatment results were not identical between NHL subtypes, with large cell lymphoma patients doing significantly better (pEFS 90%, p = .008). The use of protocols based on BFM 90 study was feasible at this center. The treatment results are approximately 10% lower than those reported by BFM investigators, but comparable to results from other centers.

Human herpesvirus-8 (HHV-8) associated with small non-cleaved cell lymphoma in a child with AIDS

The association of human herpesvirus-8 (HHV-8) with a small non-cleaved cell lymphoma is described in a child with the acquired immunodeficiency syndrome (AIDS) who developed a malignant pleural effusion and radiologic evidence of multiple solid tumors. HHV-8 DNA and Epstein-Barr virus DNA were identified in pleural fluid cells by polymerase chain reaction (PCR) amplification. The serum antibody titer against lytic HHV-8 proteins was 1:640; antibodies to latent HHV-8 proteins were not detected. Cytogenetic analysis of malignant cells revealed three abnormal karyotypes sharing the common finding of a t(8;14) translocation. Rearrangement of c-myc was demonstrated by PCR analysis. Oligoclonal JH immunoglobulin bands were found. Insufficient pleural fluid cells were available to permit localization of HHV-8 to malignant cells by in situ hybridization. This malignancy contrasts with HHV-8-associated lymphomas reported in adult patients with AIDS with respect to cell morphology, c-myc translocation, and oligoclonal immunoglobulin gene rearrangement. HHV-8 is associated with a wider spectrum of malignancies than recognized previously.

Treatment of children and adolescents with non-Hodgkin's lymphoma (results based on the NHL Berlin-Frankfurt-Münster 90 protocols)

BACKGROUND

To determine the feasibility and results of treating children with non-Hodgkin's lymphomas (NHL) according to very intensive protocols based on the German Berlin Frankfurt Münster NHL 90 study.

METHODS AND RESULTS

From 1991 until 1995 eighty two patients less than 18 years of age with NHL were admitted to our department. Sixty three of them were eligible for the study. The entire group consisted of 43 males and 20 females (ratio 2.1:1). Median age was 10 2/12 years. Eleven had stage I disease, 4 stage II, 29 stage III and 19 stage IV disease. Histologies represented were: large cell lymphoma 22, lymphoblastic lymphoma 19, and Burkitt lymphoma 10 patients. In 12 cases the immunophenotype was not further classified as to B-cell or T-cell subtype. Patients were stratified into the therapy groups "B" or "non B" according to histopathology, clinical stage and LDH level. Therapy for the B group consisted of 2, 4 or 6 courses of intensive 5 day pulses of 6 drugs. Patients in the non B group received the protocol for acute lymphoblastic leukemia including reinduction and CNS irradiation for advanced stages. At a median follow-up of 35 months the probability of event free survival (pEFS) at 5 years 70% and overall survival 73% for entire group. For therapy group B pEFS was 76%. The non B therapy group had a pEFS 60% (p = 0.22). There was a significantly better outcome for children classified as stage I and II. There was no statistical difference between stage III and IV. Treatment results were comparable between NHL subtypes, except for large cell lymphomas, which did significantly better (pEFS 90%).

CONCLUSIONS

The use of protocols based on BFM 90 study in the Czech Republic was feasible. The pEFS are approximately 10% lower than the German study but comparable to some other studies. Outcome for large cell lymphomas was excellent. Reduction of treatment related complication and mortality rate as well as more precise classification are required.

Characterization of natural Epstein-Barr virus infection and replication in smooth muscle cells from a leiomyosarcoma

Cells from a leiomyosarcoma tumor (LMS-1) from a patient with the acquired immunodeficiency syndrome (AIDS) were explanted, cultured in vitro, and studied by phase-contrast microscopy for morphologic and growth characteristics, immunostaining for cell markers, EBER in situ hybridization and polymerase chain reaction for detection of Epstein-Barr virus (EBV), and immunostaining for expression of EBV antigens. The cells exhibited very slow growth in vitro, with unusual elliptical and spindle-shaped morphology and fragmentation of the cytoplasm into long, tapering, cytoplasmic processes. Greater than 90% of cells expressed diffuse distribution of the smooth muscle isoform of actin by immunoperoxidase staining. Approximately 25% of cells expressed very bright fluorescence by immunostaining of the smooth muscle isoforms of calponin and actin. The majority of cells demonstrated a weak signal for CD21; approximately 5-10% of cells showed a strong signal that was confined to cell surfaces. The cultured cells harbored EBV, and infectious EBV continued to be detected by polymerase chain reaction and virus culture through several passages in vitro. Several EBV antigens were expressed, including latent antigen EBNA-1, immediate-early antigen BZLF1, early antigen EA-D, and late antigens, including viral capsid antigen p160, gp125, and membrane antigen gp350. Human umbilical cord lymphocytes that were transformed with virus isolated from cultured cells yielded immortalized cell lines that expressed EBV antigens similar to other EBV-transformed lymphocyte cell lines. These results confirm that EBV is capable of lytic infection of smooth muscle cells with expression of a repertoire of latent and replicative viral products and production of infectious virus. EBV infection of smooth muscle cells may contribute to the oncogenesis of leiomyosarcomas.

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.

Role of staging bone marrow examination in children with Hodgkin disease

PURPOSE

To determine the value of bone marrow trephine biopsy as part of the clinical staging for children presenting with Hodgkin disease.

PATIENTS AND METHODS

A retrospective study of pre-treatment bone marrow examinations was undertaken to examine the value of bone marrow staging in children with Hodgkin disease. The records of 122 children, diagnosed with Hodgkin disease at Texas Children's Hospital between February 1960 and July 1996 were reviewed. Age, sex, complete blood counts (CBC), pathology, and clinical and pathological staging results were tabulated.

RESULTS

Information was complete for analysis in 110 patients. Bone marrow trephine biopsies identified Hodgkin disease in 2/110 patients (1.8%). The patients with bone marrow disease had clinical stage IIIB disease prebiopsy. Positive bone marrow biopsy results did not effect a change in therapy, and the small number of positive cases do not allow any prediction as to prognosis.

CONCLUSION

There is no role for bone marrow trephine examination in children with clinical stage I-IIIA Hodgkin disease.

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.

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.

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.

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.

Measurement of residual leukemia during remission in childhood acute lymphoblastic leukemia

BACKGROUND

Complete remission of B-precursor acute lymphoblastic leukemia (ALL) has traditionally been defined as the near absence of lymphoblasts in a light-microscopical examination of stained bone marrow smears, but a patient in remission may still harbor up to 10(10) leukemia cells. We investigated whether there is a relation between the outcome of treatment and submicroscopic evidence of residual disease.

METHODS

We conducted a prospective study of patients during a first clinical remission using a quantitative polymerase-chain-reaction (PCR) assay capable of detecting 1 viable leukemia cell among 200,000 normal marrow mononuclear cells and a clonogenic blast-colony assay. Bone marrow specimens from 24 children were sequentially evaluated during a five-year period, and the results were compared with the clinical outcome.

RESULTS

Seven patients relapsed and 17 remained in remission 2 to 35 months after the completion of treatment. The levels of residual leukemia-cell DNA in the two groups were significantly different (P<0.001; 95 percent confidence interval for the difference in the mean log-transformed ratio of leukemia-cell DNA to normal bone marrow-cell DNA, 0.38 to 1.28). Autoregression analyses identified trends for individual patients that were associated with relapse. Despite continued remission in 17 patients, evidence of residual leukemia was detected by PCR in 15 and by both PCR and blast-colony assays in 7.

CONCLUSIONS

Molecular signs of residual leukemia can persist up to 35 months after the cessation of chemotherapy in children with ALL in remission. This suggests that eradication of all leukemia cells may not be a prerequisite for cure.

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.

Incidence of childhood and adolescent cancer in Texas

Population-based data from the Texas Cancer Registry were used to describe the incidence of cancer in 1990 among Texas residents younger than 20 years. A total of 788 primary malignant neoplasms were diagnosed. Higher incidence of all cancers was observed among Texas Anglo children compared with Hispanics or African-Americans, and lower rates of central nervous system (CNS) neoplasms were seen among Hispanics. Compared with national data, significantly fewer cases of all cancers combined, non-Hodgkin's lymphoma, neuroblastoma, and CNS neoplasms were seen in Texas Hispanics. The overall incidence of leukemia and acute nonlymphocytic leukemia (ANLL) was highest in Hispanics compared with other Texas children, and a three-fold statistically significant excess of ANLL was evident in Hispanic females compared with national whites. In summary, the incidence of cancer in Texas Hispanic children and adolescents differs from that seen in other racial and ethnic groups. Incidence data for Texas provide additional insight into the descriptive nature of childhood and adolescent cancers.

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.

Association of Epstein-Barr virus with leiomyosarcomas in young people with AIDS

BACKGROUND

Children with the acquired immunodeficiency syndrome (AIDS) have an unusually high incidence of smooth-muscle tumors (leiomyomas and leiomyosarcomas) in addition to malignant lymphomas. We tested the hypothesis that the smooth-muscle tumors in these children are associated with the Epstein-Barr virus (EBV).

METHODS

Tissue specimens of five leiomyosarcomas and two leiomyomas from six children with AIDS were studied for evidence of the human immunodeficiency virus (HIV) and EBV by in situ hybridization and quantitative polymerase chain reaction (PCR). Comparison specimens included samples of leiomyosarcoma and leiomyoma from HIV-negative children. EBV clonality of leiomyosarcomas was determined by Southern blot analysis with oligonucleotide probes for EBV terminal-repeat fragments. Tumor specimens were tested by immunoperoxidase staining for infiltration by B lymphocytes and expression of the EBV receptor. Serologic testing for EBV was performed.

RESULTS

In situ hybridization showed EBV genomes in all muscle cells of the five leiomyosarcomas and the two leiomyomas from the six HIV-infected children. Quantitative PCR demonstrated strikingly high levels of EBV in tumor tissue, with as many as 4.3 genome copies per cell. Two colonic leiomyosarcomas obtained from different sites at different times from one patient contained different episomal EBV clones, signifying the presence of distinct monoclonal EBV-related tumors. We found biclonal EBV infection in the leiomyosarcoma of another patient. No EBV was detected in normal muscle or tumor specimens from HIV-negative patients. Immunostaining for the EBV receptor was strongly positive in six of the seven leiomyomas and leiomyosarcomas from the patients with AIDS.

CONCLUSIONS

EBV can infect smooth-muscle cells, at least in patients with AIDS, and it may contribute to the pathogenesis of leiomyomas and leiomyosarcomas in children with AIDS. EBV seems to play no part in smooth-muscle tumors in HIV-negative children.

Respiratory contamination of polymerase chain reactions by human herpesvirus 6

Human herpesvirus type 6 DNA derived from human breath was discovered to contaminate PCR reactions during routine reaction preparation. Parallel PCR experiments were conducted in which expiratory secretions were blocked by a surgical mask, while others were performed without any attempt to circumvent respiratory contamination. The experimenter was previously determined to harbor HHV-6 DNA in the saliva. All reactions in which expiration was obstructed were negative for HHV-6 DNA via PCR. Reactions in which there was no attempt to obstruct respiratory secretions were positive for HHV-6 DNA. These data suggest that PCR assays investigating the presence of HHV-6 may be highly susceptible to contamination from the experimenter leading to false positive results.

Childhood idiopathic thrombocytopenic purpura: association with human parvovirus B19 infection

PURPOSE

Infection with human parvovirus B19 is the most common cause of transient aplastic crisis in patients with chronic hemolytic anemia. Multiple reports of children with simultaneous B19 infection and thrombocytopenia as well as the known association between experimental B19 infection and thrombocytopenia prompted us to hypothesize that B19 may be associated with childhood idiopathic, or immune, thrombocytopenic purpura (ITP). Because there is a paucity of evidence regarding a viral etiology for ITP, we performed a comprehensive study to explore its possible relationship to B19 infection.

PATIENTS AND METHODS

Thirty-five previously healthy children with ITP were studied prospectively. Bone marrow and peripheral blood were analyzed for B19 DNA using the polymerase chain reaction (PCR). Serum was analyzed for anti-B19 immunoglobulin (Ig) M and IgG antibodies using a B19 VP1 antigen-based enzyme-linked immunosorbent assay. Fourteen healthy children served as controls for peripheral blood PCR and serologic analyses.

RESULTS

The presenting clinical and laboratory features of the study population were typical of classic ITP. Seventeen of the 35 patients (49%) had evidence of B19 DNA in the peripheral blood, bone marrow, or both. Six of 35 (17%) had anti-B19 IgM antibodies. Eight of 35 (23%) were anti-B19 IgG seropositive. The control group had no positive PCR or anti-B19 IgM specimens.

CONCLUSIONS

Our results suggest that infection with human parvovirus B19 may be associated with childhood ITP. More investigation is warranted regarding the role of PCR methodology and serologic detection methods in defining B19 pathobiology as it relates to ITP.

Prolongation of the prothrombin time after organophosphate poisoning

Prolongation of the prothrombin time owing to a transient reduction in factor VII activity is described in a 14-month-old child with organophosphate poisoning. Correction after vitamin K administration suggested an organophosphate-related effect on vitamin K-dependent factor VII activity. Historically, coagulation screening has not been routinely recommended after organophosphate intoxications. We suggest, however, that routine screening in such patients may be important. A brief review of organophosphate poisoning and the unique features of our case are presented.

Langerhans'-cell histiocytosis (histiocytosis X)--a clonal proliferative disease

BACKGROUND

The lesions of Langerhans'-cell histiocytosis (histiocytosis X), a proliferative histiocytic disorder of unknown cause, contain histiocytes similar in phenotype to dendritic Langerhans' cells. The disease ranges in severity from a fatal leukemia-like disorder to an isolated lytic lesion of bone. Intermediate forms of the disease are usually characterized by multiorgan involvement, diabetes insipidus, and a chronic course.

METHODS

To determine whether Langerhans' histiocytosis is a polyclonal reactive disease or a clonal disorder, we used X-linked polymorphic DNA probes (HUMARA, PGK, M27 beta[DXS255], and HPRT) to assess clonality in lesional tissues and control leukocytes from 10 female patients with various forms of the disease. Lymphoid clonality was also assessed by analysis of rearrangements at immunoglobulin and T-cell-receptor gene loci.

RESULTS

The HUMARA assay detected clonal cells in the lesions of 9 of the 10 patients: 3 patients had acute disseminated disease, 3 had unifocal disease, and 3 had intermediate forms. The percentage of clonal cells closely approximated the percentage of CD1a-positive histiocytes in each lesion. Clonality was also confirmed in two of nine cases with the PGK or M27 beta probe. Extreme constitutional lyonization precluded assessment of clonality in the 10th case. Lymphoid clonality was ruled out in all cases.

CONCLUSIONS

The detection of clonal histiocytes in all forms of Langerhans'-cell histiocytosis indicates that this disease is probably a clonal neoplastic disorder with highly variable biologic behavior. Thus, genetic mutations that promote clonal expansion of Langerhans' cells or their precursors may now be identified.

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.

The role of tranexamic acid in the treatment of giant hemangiomas in newborns

Giant hemangiomas occurring in the neonatal period often present a therapeutic challenge, especially when confounded by consumptive coagulopathy (Kasabach-Merritt syndrome). We treated three infants with tranexamic acid after therapy with corticosteroids was ineffective. One patient had a partial response. The remaining two developed progressive disease.

B19 parvovirus-induced anemia in a normal child. Initial bone marrow erythroid hyperplasia and response to intravenous immunoglobulin

PURPOSE

Human B19 parvovirus infection may cause severe erythroid hypoplasia in patients with an underlying hemolytic anemia. We report a case of severe parvovirus-induced anemia with initial marrow erythroid hyperplasia in a child with no underlying hematologic disorder.

CONCLUSIONS

The patient's rapid hemoglobin recovery after treatment with i.v. immunoglobulin further supports this form of therapy for children with parvovirus-induced anemia.

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.

Infection-associated hemophagocytic syndrome. Evidence for Epstein-Barr virus gene expression

Autopsy specimens from a patient with infection-associated hemophagocytic syndrome (IAHS) were evaluated for the presence of Epstein-Barr virus DNA and RNA using in situ hybridization. Frozen sections of liver, lymph node, and spleen were probed with EBV Bam HI-H & W, gamma interferon, and SP-65 plasmid DNA as a negative control probe. Hybridization patterns before and after treatment with ribonuclease A were examined. Both EBV probes produced diffuse hybridization throughout the tissues; in addition, there were some foci of extremely heavy concentrations of silver granules. A gamma interferon probe showed evidence of hybridization, but the overall intensity was not as great as with EBV probes. Pretreatment with ribonuclease A dramatically decreased hybridization in all tissues to EBV probes, but hybridization with SP-65 was unaffected. The elimination of EBV hybridization with ribonuclease A pretreatment provides the first evidence of EBV gene expression in an IAHS patient.

Primary leptomeningeal B-cell lymphoma in a 8-year-old child

A case of primary leptomeningeal B-cell lymphoma in an 8-year-old, previously healthy child is described. The child was found to have hypogammaglobulinemia, and the Epstein-Barr virus genome was identified in cultured tumor cells despite blood serology being negative for the virus. The patient was treated with cyclophosphamide, doxorubicin, vincristine, and dexamethasone, plus intrathecal methotrexate, and initially improved. Before the initiation of craniospinal radiation, the patient developed progressive disease, deteriorated, and died 9 months after the onset of symptoms.

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.

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.

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.

Successful outcome of severe aplastic anemia following Epstein-Barr virus infection

Severe aplastic anemia has been reported in children following Epstein-Barr virus (EBV) infection. The pathophysiology of disease is not known, but an immunologic mechanism is suspected because of the rapid response to steroids. A patient with severe aplastic anemia following EBV infection experienced bone marrow recovery after treatment with high-dose prednisone. After reviewing the literature it is concluded that steroid therapy is indicated in this select group of patients.

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.

Clonal rearrangement for immunoglobulin and T-cell receptor genes in systemic Castleman's disease. Association with Epstein-Barr virus

Castleman's disease is a morphologically and clinically heterogeneous lymphoproliferative disorder. Both a localized benign variant and an aggressive form with systemic manifestations have been described. To investigate the differences between these variants of Castleman's disease, the authors analyzed lymph node DNA from 4 patients with the localized type and 4 with the systemic type of Castleman's disease for immunoglobulin and T-cell receptor gene rearrangements. The role of Epstein-Barr virus (EBV) and cytomegalovirus (CMV) was also studied by viral genomic DNA probes. They detected clonal rearrangements in 3 of the 4 patients with the systemic variant of Castleman's; no patients with localized disease had rearrangements. Copies of EBV genome were also detected in 2 of the 3 patients with clonal rearrangements. These results suggest that systemic Castleman's disease is a disorder distinct from the classical localized variant in that it may evolve into a clonal lymphoproliferation.

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.

The accelerated phase of Chediak-Higashi syndrome. An expression of the virus-associated hemophagocytic syndrome?

The clinical and pathologic findings of four patients with Chediak-Higashi syndrome in the accelerated phase were studied in order to clarify the nature of this enigmatic process. Fever, lymphadenopathy, hepatosplenomegaly, and cytopenias were present in every patient. All cases demonstrated extensive parenchymal infiltrates in many organs composed of benign-appearing histiocytes manifesting hemophagocytosis accompanied by lymphocytes and plasma cells. Studies in one patient suggested a viral etiology with the findings of a low blood lymphocyte OKT4 to OKT8 ratio, acquired loss of lymphocyte response to mitogens, the presence of Epstein-Barr virus genome in the mononuclear cells of lymph node, blood, and bone marrow, and possible clinical responses to acyclovir. It is concluded that the accelerated phase of Chediak-Higashi syndrome may be the clinicopathologic expression of the virus-associated hemophagocytic syndrome.

Leukemia cutis treated with total skin irradiation

An infant with acute monoblastic leukemia who presented with an extramedullary mass and involvement of the bone marrow, cerebrospinal fluid, and skin is described. After achieving remission, she later developed a relapse that was isolated in the skin. Superficial electron beam irradiation to the total skin surface was administered as therapy for the relapse. She remains in remission 12 months following this treatment. The isolated nature of the skin relapse, in addition to the fact that the relapse did not involve a previously irradiated field, suggests that the skin may have harbored the leukemic cells since the time of diagnosis. Cytogenetic data is presented that lends further support to this hypothesis.

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.