Follicular mucinosis associated with imatinib (STI571)

Sir, The development of the specific inhibitor of BCR‐ABL tyrosine kinase, imatinib mesylate, is a notable success in the treatment of chronic myeloid leukaemia (CML).1 However, most patients treated with imatinib experience mild to moderate side‐effects. The haematological adverse effects include anaemia, thrombocytopenia and neutropenia, while superficial oedema, nausea, muscle cramps and skin eruptions are also observed as some of the nonhaematological adverse effects.2 As imatinib maintains its therapeutic effects through a novel molecular targeting strategy, it may also be involved in various types of pharmacological and allergic reactions in the skin that have never been identified until now. We report a CML patient who developed follicular mucinosis during the course of her treatment with imatinib. A 53‐year‐old Japanese woman was referred to the Department of Dermatology, Hokkaido University Graduate School of Medicine, with an itchy eruption on her face. She had been diagnosed as having CML a year before and was immediately given imatinib at a daily dose of 300–600 mg. A facial eruption appeared 2 months after the initiation of imatinib treatment, although she had already achieved a complete haematological remission with a complete cytogenetic response. Afterwards the skin lesion gradually expanded and infiltrated. On physical examination the lesion revealed a symmetrical, indurated plaque with slight erythema extending from the dorsum of her nose to the cheeks (Fig. 1). Her past history was unremarkable. Her family history indicated that her father had suffered from colon cancer at the age of 62 years.