Primary cutaneous aggressive epidermotropic CD8+ T-cell lymphoma: proposed diagnostic criteria and therapeutic evaluation.

Primary cutaneous aggressive epidermotropic CD8(+) T-cell lymphoma is a rare cytotoxic lymphoma characterized clinically by aggressive behavior and histologically by prominent epidermotropism of atypical CD8(+) lymphocytes. Despite the continuous addition of new case reports, no definite diagnostic criteria have been established, and an optimum treatment is still awaiting. Herein, we study and analyze the different clinical, histopathological, and immunohistochemical features described in the reported cases. Different therapeutic modalities and their impact on the prognosis of the tumor are also evaluated and presented. We propose two sets of diagnostic criteria. The first comprises constant clinical, histopathological, and immunohistochemical features that are always present in every case, and the combination of which is necessary for the diagnosis. The second set helps to avoid missing cases and includes variable features that may be present in some cases, and to which any emerging finding could be added. Although different therapeutic options have been used, either as single agents or in combinations, there is no standard therapy for primary cutaneous aggressive epidermotropic CD8(+) T-cell lymphoma and the tumor still represents a therapeutic challenge with very poor prognosis.