Is there a cutaneous variant of marginal zone hyperplasia?

Identifying and addressing unmet clinical needs in primary cutaneous B-cell lymphoma: A consensus-based paper from an ad-hoc international panel

Primary cutaneous B-cell lymphomas (PCBCLs) are lymphoproliferative disorders that appear on the skin without evidence of extracutaneous manifestations at the time of diagnosis. There is a lack of evidence-based guidelines for their clinical management due to the availability of very few large scale studies and controlled clinical trials. Here we present and discuss a series of major unmet clinical needs (UCNs) in the management of PCBCLs by a panel of 16 experts involved in research and clinical practice of PCBCL. The Panel produced recommendations on the appropriateness of the clinical decisions concerning the identified clinical needs and proposed research for improving the knowledge needed to solve them. Recommendations and proposals were achieved by multiple-step formalized procedures to reach a consensus after a comprehensive analysis of the scientific literature. Recommendations and proposals lay in the domain of classification uncertainties of PCBCL, optimization of diagnosis, optimization of prognosis, optimization of staging and critical issues on therapeutic strategies with particular focus on new treatments. These recommendations are intended for use not only by experts but above all by dermatologists and hematologists with limited experience in the field of PCBCLs as well as general practitioners.

Cutaneous Hematolymphoid and Histiocytic Proliferations in Children

This article focuses on cutaneous hematopoietic neoplasms that are more likely to be encountered in the pediatric age-group and includes both lymphoproliferative and histiocytic disorders. The cutaneous hematologic disorders in children have a different epidemiologic profile to what is seen during adulthood. Although mycosis fungoides is the most frequent form of cutaneous lymphoma in adults, it is very rare in children. Because lymphoblastic leukemias and lymphomas are more frequent in the pediatric setting, cutaneous leukemic infiltrates are relatively common in this age-group. Similarly, histiocytic disorders are more common in children, particularly Langerhans cell histiocytosis and juvenile xanthogranuloma. Notably, the histiocytic disorders have undergone significant modifications on their nomenclature in the basis of the molecular characteristics that are present in them. A summary of the most frequent cutaneous hematopoietic disorders in children will be discussed further in this review.

Pediatric-type Follicular Lymphoma and Pediatric Nodal Marginal Zone Lymphoma: Recent Clinical, Morphologic, Immunophenotypic, and Genetic Insights

Pediatric-type follicular lymphoma and pediatric nodal marginal zone lymphoma are 2 of the rarest B-cell lymphomas. Although they are both predominantly seen in children, they can manifest in the adult population as well. Our understanding of these lymphomas has advanced rapidly in recent years such that we not only have a firm grasp of the morphologic and immunophenotypic findings, but also have a deeper insight into critical genetic and molecular pathways of these diseases. This review will cover the clinical and pathologic characteristics, treatment, prognosis, and important differential diagnoses of these entities.

Cutaneous marginal zone lymphomas

Primary cutaneous marginal zone lymphoma (CMZL) is one of the major primary B-cell lymphomas of skin. Two types are recognized: a more common class-chain switched CMZL, and a much less common IgM+ CMZL. The extremely indolent course, together with other features distinct from most other MALT lymphomas, has led some to question whether at least the class-switched cases should be considered an overt lymphoma.

Cutaneous B-cell lymphoproliferative disorders: report of the 2011 Society for Hematopathology/European Association for Haematopathology workshop

The diagnosis and classification of the cutaneous B-cell lymphomas can be quite a challenge, with a definitive diagnosis sometimes being elusive, even when an extensive workup has been performed. Distinction of benign from neoplastic disorders can be difficult, with some hyperplasias mimicking lymphomas and vice versa. There are only a limited number of skin-specific B-cell lymphomas, including primary cutaneous follicle center lymphoma and primary cutaneous diffuse large B-cell lymphoma, leg type. Cutaneous marginal zone lymphomas have distinctive features but are classified with the other mucosa-associated lymphoid tissue lymphomas. It is important, however, to also remember that many other B-cell lymphomas/ plasma cell neoplasms can primarily, or more often secondarily, involve the skin. Some may mimic one of the skin-specific lymphomas but have very different clinical implications. Iatrogenic and senescent immunodeficiency-associated lymphoproliferative disorders that are often Epstein-Barr virus (EBV) positive can also primarily involve the skin, including cases also known as EBV-positive mucocutaneous ulcer.

Marginal zone lymphomas in children and the young adult population; characterization of genetic aberrations by FISH and RT-PCR

Marginal zone lymphomas present rarely in children and young adults as either primary nodal or extranodal disease and have an excellent prognosis. To date, chromosomal aberrations have not been analyzed in the pediatric and young adult population. We undertook a study to analyze genetic alterations in nodal and extranodal marginal zone lymphomas in children and young adults using fluorescence in situ hybridization (FISH) and RT-PCR. These findings were correlated with clinical features at presentation and immunophenotype. Forty-one cases were identified meeting these criteria. The age range was 1.5-29 years old with 49% of the cases <18 years of age. 73% of the marginal zone lymphoma cases showed evidence of light chain restriction by immunohistochemistry or flow cytometry. CD43 was coexpressed in 83%. 85% of the marginal zone lymphoma cases tested showed evidence of immunoglobulin heavy chain gene rearrangement. Fifty-nine percent of the cases were nodal marginal zone lymphomas with a median age at presentation of 16 years and an M/F ratio of 7:1. Twenty-one percent of the nodal marginal zone lymphoma cases contained genetic aberrations. Seventeen percent contained trisomy 18 with one case containing an additional trisomy 3. A translocation of the immunoglobulin heavy chain gene to an unknown partner gene was present in one case. Forty-one percent of the cases were extranodal marginal zone lymphomas with a median age of 24 years and a M/F ratio of 1.4:1. Eighteen percent of the extranodal marginal zone lymphoma cases contained genetic aberrations. The t(14;18) involving the IGH and MALT1 genes was present in one case, tetraploidy was present in one case, and another case contained trisomy 3. Overall the incidence of genetic aberrations in marginal zone lymphomas in the pediatric and young adult population is low, but the aberrations seen are similar to those seen in the adult population.