Lymphoreticular pathology of the head and neck region: a review of selected entities

Abstract In routine surgical pathology lymphoid proliferations are seen fairly frequently. It is important to be aware of commonly seen reactive and inflammatory pathologies, as well as malignant lymphomas of the MALT tissue and nodal involvement by lymphomas. Several of the reactive pathologies have striking morphological features such that haematoxylin and eosin stained slides are sufficient in arriving at a diagnosis. There are several pathological entities in which Ebstein-Barr virus has a role to play, including both benign and malignant proliferations. Most high-grade lymphomas have a worrying morphological appearance and immunohistochemistry is helpful in confirming the diagnosis. More problematic are dense lymphoid infiltrates where the differential diagnosis lies between a reactive versus a low grade lymphoma; immunohistochemistry is vital in such situations. In addition, there are entities specific to the head and neck region, such as an extranodal NK/T-cell lymphoma, nasal type. Careful clinical and radiological correlation is vital.