Two cases of merkel cell tumour arising in patients with chronic lymphocytic leukaemia.

Chronic lymphocytic leukaemia (CLL) has been associated with an increased incidence of second neoplasms, especially skin cancers such as basal and squamous cell carcinomas. No association with the rarer skin cancer, the Merkel cell tumour (MCT), has previously been reported. Two patients with MCT had a previous diagnosis of CLL. MCT is an aggressive skin cancer, as up to 45% of patients have lymph node involvement at presentation and 5-year disease-free survival is as low as 30%. It is most commonly found on sun-exposed areas of the body, and ultraviolet radiation together with drug-induced or CLL-induced immunosuppression may be the underlying mechanism in the observed relationship between CLL and other skin cancers.