Indolent CD8(+) lymphoid proliferation of acral sites: a clinicopathologic study of six patients with some atypical features.

The authors report six further cases of a cutaneous lymphoid proliferation that share many of the features of a case series previously described as indolent CD8-positive lymphoid proliferation of the ear. Previous reports of this entity have described the slow growth of cutaneous papules and nodules, with a predilection for the ear, associated with specific histopathologic and immunophenotypic features and a benign clinical course. These include the presence of a clear Grenz zone without epidermotropism, and a CD8+ granzyme B- immunophenotype with a low proliferative index. The current case series presents some atypical clinical features, including site of disease beyond the ear and recurrent disease. Despite this, indolent clinical evolution is apparent. Histopathologically, three of the six cases showed a moderate-high proliferative index, while two cases had very focal epidermotropism and Pautrier collections. A single example had significant granzyme B expression. These previously unreported features add to our understanding of this rare entity, which is not currently recognized in the World Health Organization (WHO)/European Organization for Research and Treatment of Cancer (EORTC) classification.