Primary large-cell lymphomas of the mediastinum

The mediastinum is a frequent site of involvement for malignant lymphoma, T he most common types encountered in this location include Hodgkin's and non -Hodgkin's lymphoma and lymphoblastic lymphoma, With the exception of lymph oblastic lymphoma in children and adolescents, most cases of mediastinal in volvement by lymphoma represent part of systemic disease and do not general ly pose difficulties for diagnosis, However, a relatively small group of tu mors have become increasingly recognized in recent years that are primarily localized in the anterior mediastinum and show features of nonlymphoblasti c/non-Hodgkin's large-cell lymphoma. Because such tumors are capable of ado pting unusual morphological appearances, they can often pose difficulties f or diagnosis and be frequently mistaken for other conditions. This review d iscusses this group of neoplasms collectively known as diffuse large-cell l ymphoma of the mediastinum. The clinicopathologic, immunohistochemical, and molecular genetic aspects of these tumors appear to indicate that a signif icant proportion of them may correspond to a distinctive type of lymphoprol iferative process most likely arising from a native B-cell population of th e thymus, thus representing, in essence, a primary extranodal large-B-cell lymphoma of the thymus, Copyright (C) 1999 by W.B. Saunders Company.