Transformed diffuse large B-cell lymphoma from marginal zone lymphoma in the anterior mediastinum: A case report and review of the literature.

Marginal zone lymphoma (MZL) arising from the anterior mediastinum is rare. In the majority of reported cases, the tumor was incidentally discovered, reflecting its indolent clinical features. We present a 38-year-old woman who had no medical history, and presented with a bulky anterior mediastinal tumor complicated by life-threatening compression of the vasculature and bronchi. Biopsy specimens of the neoplasm suggested transformed diffuse large B-cell lymphoma (DLBCL) from MZL. To our best knowledge, this is the first case report of anterior mediastinum MZL associated with an aggressive clinical course and life-threatening complications likely due to transformation to DLBCL.