Indolent CD8-positive lymphoid proliferation of acral sites: three further cases of a rare entity and an update on a unique patient.

Background: Primary cutaneous indolent CD8-positive lymphoid proliferation is an emerging entity characterized by slowly enlarging papules and nodules that are pathologically comprised of clonal nonepidermotropic medium-sized atypical CD8(+) T-cells. Although the majority of lesions are solitary and located on the ears, bilateral symmetrical presentations have been described and lesions may arise at other peripheral or 'acral' sites. Patients follow a benign clinical course and systemic involvement has not yet been observed.

Immunocytochemical p63 expression discriminates between primary cutaneous follicle centre cell and diffuse large B cell lymphoma-leg type, and is of the TAp63 isoform.

Aims: The p63 gene shares structural and functional homologies with the p53 family of transcriptional activators, but differs in exhibiting a consistent expression pattern in normal tissues. Although p63 is rarely mutated in malignancy studies of primary human tumours and cell lines suggest that p63 may promote tumour development. In non-Hodgkin's nodal lymphoma, TAp63 expression in follicular lymphoma (54%) and diffuse large B cell lymphoma (34%) has been described and correlated with the proliferative index.