Cutaneous B-Cell Lymphomas.

Primary cutaneous B-cell lymphomas represent a type of non-Hodgkin's lymphoma of the skin without evidence of extracutaneous involvement at the time of diagnosis. According to the 2018 World Health Organization-the European Organization for Research and Treatment of Cancer classification, primary cutaneous B-cell lymphomas include primary cutaneous marginal zone lymphoma, primary cutaneous follicle center lymphoma, primary cutaneous diffuse large B-cell lymphoma, leg type, intravascular large B-cell lymphoma, and Epstein-Barr virus+ mucocutaneous ulcer (provisional). Herein, we provide a comprehensive review of the updated literature on these entities, including clinical presentation, histopathology, immunophenotype, molecular genetics, prognosis, and treatment.

A Practical Review of the Presentation, Diagnosis, and Management of Cutaneous B-Cell Lymphomas.

This review of cutaneous B-cell lymphoma (CBCL) is focused on the clinical presentation, treatment, and workup of each type of lymphoma. Part 1 is an overview of each of the CBCLs, including clinical presentation, recent advances in the pathobiology, and evidence regarding treatment strategies. Part 2 is a detailed guide to the steps in diagnosis and workup of a newly diagnosed CBCL according to the International Society for Cutaneous Lymphoma/European Organization for Research and Treatment of Cancer and NCCN guidelines.

A distinctive subgroup of oral EBV+ B-cell neoplasm with polymorphous features is potentially identical to EBV+ mucocutaneous ulcer.

Epstein-Barr virus-positive mucocutaneous ulcer (EBVMCU) is a newly recognized provisional entity included in mature B-cell neoplasm in the latest 2016 World Health Organization Classification. It has a self-limited growth potential with a high predilection for oral cavities and occurs in age-related or iatrogenic immunodeficiency with indolent clinical courses. However, it shares histological features with EBV-positive diffuse large B-cell lymphoma (DLBCL), and this often leads to diagnostic challenges and controversies in patients with an oral EBV-positive B-cell neoplasm. The aim of this study was to better characterize and comprehend the pathophysiology of DLBCL and EBVMCU in the oral cavity. We conducted clinicopathologic and recurrent gene mutation analysis of 49 cases (14 EBV positive, 35 EBV negative), including cases diagnosed as DLBCL or B-cell lymphoproliferative disorders with high-grade morphology in the oral cavity. All EBV-positive cases matched the criteria of EBVMCU, with significantly earlier clinical stages than the EBV-negative group (P=.0006). Besides, histological analysis showed that all EBV-positive cases presented polymorphous features, whereas 91.4% (32/35) of the EBV-negative cases showed diffuse and monotonous proliferation (P<.0001). Furthermore, EBV-positive cases presented favorable clinical outcomes without disease-related death or recurrence. Gene mutation analysis (MYD88, CD79A, CD79B, CARD11, and EZH2) revealed that 33.3% (9/27) of EBV-negative cases harbored at least 1 gene mutation, whereas no gene mutation was observed in the EBV-positive group (0/11). These results suggest that oral EBV-positive B-cell lymphoid proliferation with polymorphous features often fulfill the criteria for EBVMCU, with clinicopathologically and genetically distinctive properties.

Epstein-Barr virus-positive mucocutaneous ulcer in Crohn's disease. A condition to consider in immunosuppressed IBD patients.

Epstein-Barr virus-positive mucocutaneous ulcer (EBVMCU) is a little known entity that can affect the oropharyngeal mucosa, the gastrointestinal tract and the skin. The main risk factor for the development of this lesion is immunosuppression. Because its features are similar to other Epstein-Barr virus-associated lymphoproliferative disorders, a differential diagnosis can sometimes prove challenging. Here, we report the case of a man diagnosed with Crohn's disease and treated with azathioprine and infliximab who developed ulceration at the rectum that was refractory to conventional medical treatment. Although the histological characteristics were suggestive of an EBVMCU, lymphoproliferative disease could not be ruled out. The patient did not improve after discontinuation of the treatment, a proctectomy was performed and the diagnosis of this disease was confirmed. Although very few cases of EBVMCU affecting the colon have been reported, its diagnosis should be always considered in refractory cases of inflammatory bowel disease with patients undergoing immunosuppressive treatment.

Epstein-Barr virus-positive mucocutaneous ulcer arising in a post-hematopoietic cell transplant patient followed by polymorphic posttransplant lymphoproliferative disorder and cytomegalovirus colitis.

Epstein-Barr virus (EBV)-positive mucocutaneous ulcer (EBVMCU) is a newly described entity occurring in elderly or iatrogenically immunocompromised patients. We describe a case of EBVMCU arising in a post-hematopoietic cell transplant patient and followed by EBV-positive polymorphic posttransplant lymphoproliferative disorder (EBV+ polymorphic PTLD). The patient, a 52-year-old woman, received chemotherapy and autologous peripheral blood stem cell transplantation for relapsed diffuse large B-cell lymphoma (DLBCL). She achieved complete remission and was followed up in an outpatient clinic after discharge. One year later, EBVMCU appeared in the tongue and exhibited spontaneous regression. Six months after the regression of the EBVMCU, she had EBV+ polymorphic PTLD, analogous to EBV+ polymorphic DLBCL. The therapy for PTLD was not effective, and the patient finally died of disease progression. This was the first case of EBVMCU characterized by both an association with autologous peripheral blood stem cell transplantation and subsequent emergence of malignant lymphoma in a patient with relapsed DLBCL.

Cutaneous EBV-related lymphoproliferative disorders.

This article will focus on the cutaneous lymphoproliferative disorders associated with EBV, with an emphasis on the upcoming changes in the revised 4th Edition of the WHO classification of tumors of the hematopoietic system, many of which deal with cutaneous disorders derived from NK-cells or T-cells. Extranodal NK/T-cell lymphoma usually presents in the upper aerodigestive tract, but can involve the skin secondarily. EBV-associated T- and NK-cell lymphoproliferative disorders (LPD) in the pediatric age group include the systemic diseases, chronic active EBV infection (CAEBV) and systemic EBV+ T-cell lymphoma of childhood. Hydroa vacciniforme (HV)-like LPD is a primarily cutaneous form of CAEBV and encompasses the lesions previously referred to as HV and HV-like lymphoma (HVLL). All the T/NK-cell-EBV-associated diseases occur with higher frequency in Asians, and indigenous populations from Central and South America and Mexico. Among the B-cell EBV-associated LPD two major changes have been introduced in the WHO. The previously designated EBV-positive diffuse large B-cell lymphoma (EBV-DLBCL) of the elderly, has been changed to EBV-DLBCL with 'not otherwise specified' as a modifier (NOS). A new addition to the WHO system is the more recently identified EBV+ mucocutaneous ulcer, which involves skin and mucosal-associated sites.