Cutaneous lymphoproliferative disorders

Cutaneous lymphoproliferative disorders (CLD) include reactive lymphoid hyperplasias, so called cutaneous "pseudolymphomas", prelymphomatous conditions and definite malignant lymphomas of low and high grade malignancy. Reactive benign lymphoid proliferations in the skin, either localized or disseminated, mimicking primary lymphoma have been termed pseudolymphomas (PSL). These either resolve spontaneously or after elimination of the causative factor (e.g. drugs). Cutaneous prelymphomatous ("abortive") disorders (PLD) include a variety of idiopathic chronic dermatoses often unresponsive to topical therapy with persistent T-cell clones that should be recognized by dermatologists. Careful characterization and follow-up of these cases is essential to ensure accurate diagnosis and to evaluate the potential progression to frank lymphoma. The WHO-EORTC is the most current and widely used classification of primary cutaneous lymphomas based on clinical, histological, immunohistochemical, molecular and cytogenetic features. Although these tumours have some morphological features in common with nodal lymphomas, some differ in their behaviour, prognosis and treatment requirements. This article summarizes the features of cutaneous lymphoproliferative disorders and provides a few case studies as examples of the major categories of disease.