INTRODUCTION: The mast cell lives a hidden life, but it is implicated in several physiological reactions. Its ability to react to different stimuli impacts a variety of conditions such as asthma, atopic dermatitis, urticaria and anaphylaxis. It is not until recent decades that the evolution of the cell has been described and its fascinating biology has only recently been depicted. We here give a review of systemic mastocytosis in regards to cell biology, diagnostic approaches and clinical practice. METHODS: A search was made in PubMed in August 2011 entering the keywords: mastocytosis,(systemic, cutaneous, aggressive), mast cell leukaemia, mast cell sarcoma, chromosome, mutation, haematology and treatment. RESULTS: Mastocytosis is characterized by an abnormal proliferation of mast cells, which accumulate in one or several organ systems, primarily the skin and bone marrow. The disease is clinically heterogeneous and varies from a relatively benign condition with isolated cutaneous lesions to a very aggressive systemic condition with a grave prognosis. The condition affects men and women equally. Children are especially affected by the cutaneous form. In most children, the condition will improve or remit spontaneously before adulthood. Mastocytosis in adults, however, is more often systemic and tends to persist. CONCLUSION: Patients with mastocytosis represent a hetero geneous group in terms of clinical presentation, management and prognosis. Furthermore, a range of medical specialties serve as the primary entrance to health services, which can be a challenge in respect of achieving uniform management. In order to improve diagnostics and management of systemic mastocytosis, the European Competence Network on Mastocytosis has been established. Patients under suspicion of systemic mastocytosis should be conferred with or referred to a haematological and a dermatological/allergological department.

The mast cell lives a hidden life, but plays an important role in many physiological processes. The cell’s ability to react on various stimuli is demonstrated by its implication in a wide range of conditions such as asthma, rhinitis, atopic dermatitis, urticaria and anaphylaxis. The cell was described by Paul Erlich in 1878 [1], but had already been linked to allergies some years earlier [2]. It is not until recent decades, however, that the evolution of the cell has been described [3, 4] and its fascinating