Linfomas cutáneos. Parte I: micosis fungoide,síndrome de Sézary y proliferaciones linfoides cutáneas CD30 positivas

CD30⁺ primary cutaneous lymphomas comprise a large group of malignant lymphoproliferative disorders that present in the skin without extracutaneous involvement at the time of diagnosis. The incidence of these lymphomas is low, at 7 to 10 cases per 100 000 population. Two types, derived from T cells (70%–85%) or B cells (15%–30%), have been identified. Hematologists and oncologists have increasingly recognized the idiosyncrasy of primary cutaneous lymphomas, as reflected in the updated classification of the World Health Organization. However, there remain nuances or small differences to consider when managing these conditions, obliging dermatologists to continue to strive to fully reconcile the various clinical pictures in future reviews of the classification of lymphoid neoplasms. A diagnosis of a primary cutaneous lymphoma is based on clinical, histopathologic, immunophenotypic, and genotypic criteria, particularly evidence of T- or B-cell lymphoid monoclonality in lesions. Also relevant are complementary tests to rule out extracutaneous involvement.     

Actualización terapéutica en linfomas cutáneos

Primary cutaneous lymphomas (PCLs) are a heterogeneous group of lymphoid tumors that originate primarily in the skin. Most PCLs (75%) are T-cell lymphomas and only 20% to 25% involve B cells. It is important to differentiate between cutaneous lymphomas and lymph node tumors given the differences in their molecular biology and clinical, histopathologic, and immunophenotypic features. Moreover, PCLs generally follow a more indolent course and require different treatments.Many treatment options are available for managing PLC's. The choice should be based primarily on the clinical stage of disease but must also take into consideration other factors, such as the patient's age and general health, the availability and accessibility of the treatment, and the cost-benefit ratio. It will be important to use a multidisciplinary approach, involving a team of expert dermatologists, hematologist-oncologists, and radiotherapists who are familiar with this rare disease. Recent years have seen the emergence of many new therapies, particularly for advanced stages of the disease and for patients whose tumors have proven refractory to treatment. The objective of this article is to review all the treatment options available to us.     

Rituximab en el tratamiento de los linfomas cutáneos B primarios: revisión

Rituximab is a chimeric mouse-human antibody that targets the CD20 antigen, which is found in both normal and neoplastic B cells. In recent years, it has been increasingly used to treat cutaneous B-cell lymphoma and is now considered an alternative to classic treatment (radiotherapy and surgery) of 2 types of indolent lymphoma, namely, primary cutaneous follicle center lymphoma and primary cutaneous marginal zone B-cell lymphoma. Rituximab is also administered as an alternative to polychemotherapy in the treatment of primary cutaneous large B-cell lymphoma, leg type. Its use as an alternative drug led to it being administered intralesionally, with beneficial effects. In the present article, we review the literature published on the use of rituximab to treat primary cutaneous B-cell lymphoma.     

Diagnóstico y tratamiento de los linfomas cutáneos primarios de células B

—Primary cutaneous B-cell lymphomas are a heterogeneous group of lymphoid neoplasms whose clinical course is indolent. They tend to remain localized to the skin and only present with extracutaneous dissemination on rare occasions. As a group, therefore, primary cutaneous B-cell lymphomas have a better prognosis than primary cutaneous T-cell lymphomas. Proper assessment of patients in whom the presence of a cutaneous B-cell lymphoma is suspected requires the appropriate correlation of clinical information, histopathological and immunophenotypical findings and molecular biological data. The definitive diagnosis should also take the specific subtype into account, according to current lymphoma classifications.Initial treatment is usually conservative, either through surgical excision, if feasible, or through conventional localized radiotherapy for the larger primary lesions or in case of recurrence. Multidrug chemotherapy is only recommended for patients with extensive skin disease, in those forms or subtypes considered to have an aggressive course or in cases with extracutaneous involvement; it is often used in combination with local radiotherapy.     

Sarcomas cutáneos: directrices para el diagnóstico y tratamiento. Dermatofibrosarcoma protuberans

Sarcomas comprise a broad group of tumors, many of whose biological behavior and aggressiveness differ from one type to another. The therapeutic approach is generally multidisciplinary and often complex. Developments in surgical and oncological dermatology during the last few decades have positioned dermatologists as specialists in the diagnosis and treatment of skin cancer. The aim of this article is to review the main soft tissue sarcomas that typically affect the skin. Dermatofibrosarcoma protuberans is a low-grade malignant sarcoma. It exhibits slow-growth, is locally invasive, and has low metastatic potential (< 3%). Mohs micrographic surgery is the treatment of choice. The COL1A1-PDGFB translocation should be analyzed in cases of unclear diagnosis and when it is necessary to identify candidates for tyrosine kinase inhibitors. Imatinib is indicated for the treatment of locally advanced and metastatic dermatofibrosarcoma protuberans.     

Aplicación de los protocolos de PCR BIOMED-2 en el análisis genotípico de los linfomas cutáneos primarios

The European Biomedicine and Health (Biomed-2) Concerted Action Project BMH4-CT98-3936 has defined standardized protocols for polymerase chain reaction (PCR) amplification of different loci of the T-cell receptor (TCR) and immunoglobulin (Ig) genes with a view to achieving greater sensitivity and specificity in the assessment of clonality of lymphoid neoplasms. To assess T-cell clonality, analysis of TCRβ gene and TCRδ rearrangements (useful in cases of Tγδ + cell neoplasms) is proposed alongside that of TCRγ. For analysis of B-cell clonality, along with the framework (FR) III segment of the IgH gene, other segments are studied (FRI, FRII) in addition to Igλ and Igκ genes or incomplete DJ rearrangements of the IgH gene and the κ deleting element. The results of the amplification are read using automatic reading systems (GeneScan) or using a heteroduplex system.     

Granulomas en dermatopatología: principales entidades. Parte II

Part 2 of this series on granulomatous diseases focuses on skin biopsy findings. Whereas the first part treated noninfectious conditions (metabolic disorders and tumors, among other conditions), this part mainly deals with various types of infectious disease along with other conditions seen fairly often by clinical dermatologists.