Non-mediastinal grey zone lymphomas and report from the workshop

Clinicopathological features of syncytial variant nodular sclerosis Hodgkin lymphoma

The syncytial variant of nodular sclerosis Hodgkin lymphoma (SV-NSHL) is uncommon, and its clinicopathological features have not been well analyzed. In this study, we collected 142 cases of SV-NSHL. There were 76 (53.5%) males and 66 (46.5%) females with a median age of 28 years (range, 12-78); 59.9% were younger than 30 years. Patients usually presented with a mediastinal mass (97.6%) and often with bulky (35.7%) and advanced stage disease (3 or 4) (39.7%). Follow-up showed that 61.1% of patients developed relapse after standard therapy. Morphologically, the neoplasms were composed of sheets or large clusters of pleomorphic neoplastic cells with a cohesive appearance that were frequently associated with necrosis. Neutrophils and eosinophils were frequent in the background, whereas small lymphocytes were decreased. Immunohistochemical analysis showed that the following markers were frequently positive: CD30 (100%), MUM1/IRF4 (96%), PAX5 (95%), PD-L1 (91%), and CD15 (80%). CD45 was negative in all cases. Epstein-Barr virus-encoded small RNA (EBER) was detected in 19% of cases. In this cohort, age above 30 years (P = .0430), presence of B-type symptoms (P = .0394), elevated serum lactate dehydrogenase level (P = .0004), and disease relapse (P = .0108) were associated with a poorer overall survival. In contrast, patients with EBER-positive neoplasms had a better survival (P = .0418). Compared with a control group of non-SV-NSHL patients, patients with SV-NSHL were associated with a poorer overall survival (P = .011). These data suggest that SV morphology is associated with a poorer prognosis in patients treated with traditional standard-of-care therapy for classic Hodgkin lymphoma.

Gray zone lymphomas in pediatric patients

Gray zone lymphomas are defined as lymphoid malignancies that cannot be reliably classified into a single distinct disease entity after all available morphologic, immunophenotypic, and molecular investigations have been performed. The 2008 World Health Organization Classification proposed 2 gray zone lesions: (1) B-cell lymphoma, unclassifiable, with features intermediate between diffuse large B-cell lymphoma and Burkitt lymphoma and (2) B-cell lymphoma, unclassifiable, with features intermediate between diffuse large B-cell lymphoma and classical Hodgkin lymphoma. These gray zone lesions are rare, especially in pediatric patients, and create a great challenge to both pathologists and oncologists because this differential diagnosis has direct implications for management strategies. In this manuscript, we report 2 cases of pediatric patients with gray zone lymphoma and review clinicopathologic features, treatment options, and outcomes of this uncommon tumor.

World Health Organization and beyond: new aspects in the pathology of an old disease

Hodgkin's lymphoma is a highly enigmatic lymphoma disease that still covers most of its secrets up to now. Much effort has been made to successfully wrest at least some of the pathogenetic particularities. The current diagnostic criteria are well established allowing hemato-pathologists to make a clear-cut distinction from other lymphomas in almost all cases. Although classic Hodgkin's lymphoma is curable in the vast majority of cases by treatment with highly aggressive drugs with or without radiotherapy, further molecular studies may lead to the identification of therapeutic targets that enable a more tailored treatment with fewer side effects.

Anaplastic large cell lymphomas: a study of 75 pediatric patients

In this article, we describe the morphologic and immunophenotypic features of 75 cases of pediatric anaplastic large cell lymphoma (ALCL). According to the World Health Organization classification, 49 cases were common subtype ALCL, and respectively, 3, 6, and 17 cases were small cell, lymphohistiocytic, or mixed histologic variants. Anaplastic lymphoma kinase positivity was detected in 90.7% of the tumors and, using a panel of 9 T-cell surface markers, 88% could be assigned to the T-cell lineage. A molecular analysis for the T-cell receptor gamma (TCR- gamma) and the heavy chain of the immunoglobulin H rearrangements was performed on 6/9 ALCLs with a null immunophenotype, and a TCR clonal pattern was detected in 5/6 cases. In addition, 94.1% were immunoreactive for 1 or more cytotoxic proteins (Tia1, granzyme B, or perforin), and 15% expressed CD56. Clusterin, CD83, and Pax5, respectively, expressed in 91.3%, 1.7%, and 0% of the ALCLs, were useful biomarkers for the differential diagnosis with Hodgkin's lymphomas.