Primary mediastinal (thymic) large B-cell lymphoma with a der(14)t(8;14)(q24;q32) and a translocation of MYC to the derivative chromosome 14 with a deleted IgH locus

Primary mediastinal large B cell lymphoma with coexisting aberrations of C-MYC and BCL-2: a case report and literature review

Primary mediastinal large B-cell lymphoma (PMLBCL) is an aggressive lymphoma characteristic with distinct clinical, morphologic, and immunophenotypic features. The rearrangements of C-MYC, BCL2 and/or BCL6 which are common in diffuse large B-cell lymphoma (DLBCL) are typically absent in PLMBCL. Here we proved a novel case of PMLBCL with concurrent rearrangements of C-MYC and BCL2. Histology showed typical pathomorphological features of PLMBCL. Fluorescent in situ hybridization (FISH) studies showed rearrangements of C-MYC and copy number variation (CNV) of BCL2 gene. It is not well known on the clinical significance of rearrangements of C-MYC and BCL2 genes in PMLBCL. The case gives evidence that cytogenetic testing is necessary for PMLBCLs to get precise clinical evaluation and appropriate treatment.

Histiocyte-rich xanthomatous pseudotumor mimicking relapse on positron emission tomography imaging in an adolescent with primary mediastinal diffuse large B-cell lymphoma

Inflammatory pseudotumors (IPTs) are rare, enigmatic lesions that may develop as a late manifestation of a reparative process. We describe the case of a teenager with primary mediastinal subtype of diffuse large B-cell lymphoma who developed an IPT at the site of the original lymphoma, mimicking relapse of disease on positron emission tomography/computed tomography imaging. This is the first report of IPT in a teenager with mediastinal lymphoma. This case is an important reminder of the limitations of positron emission tomography/computed tomography imaging in patients with lymphoma and stresses the importance of histologic confirmation of suspected treatment failure or relapse.

Cytogenetic and array comparative genomic hybridization analysis of a series of hepatoblastomas

Hepatoblastoma is the most common primary hepatic tumor in children, and only a limited number of detailed karyotypic analyses have been reported to date. In the present study, cytogenetic abnormalities were identified in nine cases of hepatoblastoma from a single institution. Among characteristic chromosomal changes detected were simple numerical aberrations, structural alterations of chromosomes 1, 2, and 8, and the recurrent unbalanced rearrangements der(4)t(1;4)(q25.2;q35.1) and der(6)t(1;6)(q21;q26). Array comparative genomic hybridization was applied in four of the cases. The combined cytogenetic, molecular cytogenetic, and histopathologic analyses are presented here, together with clinical data. The results substantially confirm previous findings of aberrations involving chromosomal loci on 1q, 2 or 2q, 4q, 6q, 8 or 8q, and 20 as significant in the development and clinical course of this disease.

Primary mediastinal B-cell lymphoma in the pediatric patient: Can a rational approach to therapy be based on adult studies?

The literature on adult and pediatric primary mediastinal B-cell lymphoma (PMBCL) was reviewed and compared. Biologically, adult PMBCL has more similarities to Hodgkin Lymphoma (HL) than diffuse large B-cell lymphoma (DLBCL). Pediatric studies suggest that the biology is similar to that in adults. Median age of children is 14.3 years and the overall survival (OS) is reported as 78.6% and event-free survival (EFS) as 67.4%. Adverse prognostic factors included LDH >500 and mass size over 10 cm, with a trend towards better survival in younger patients. Studies in adults show better survival with intensified chemotherapy and the addition of rituximab. Data on the use of radiation therapy show improved CR rates and survival with addition of involved field radiation therapy (IFRT). Positron emission tomography (PET) with computerized tomography (CT) imaging response-assessment after two courses and at therapy-end may allow for the rational use of IFRT in pediatric/adolescent patients who are more susceptible to development of adverse late effects.