mastocytosis

Mastocytosis is a clonal myeloproliferative neoplasm characterized by the abnormal proliferation and accumulation of mast cells in one or several organs. The condition is linked with pathogenic variants in the KIT gene, which plays an important role in cell growth and survival. It presents with a wide spectrum of clinical manifestations, ranging from localized cutaneous lesions to aggressive systemic involvement. In terms of prevalence, mastocytosis is relatively common among rare diseases, affecting approximately 1 to 5 individuals per 10,000.

The clinical presentation of mastocytosis can be highly variable. Many individuals experience skin changes such as lesions historically described as urticaria pigmentosa; others may develop systemic symptoms including episodes of itching, abdominal discomfort, and flushing. As the disease can affect various organ systems, some patients may also present with signs related to gastrointestinal or cardiovascular involvement. Not all individuals experience all features, and severity varies considerably.

Mastocytosis is driven by the clonal proliferation of mast cells, with pathogenic variants in the KIT gene being central to the condition. The KIT gene encodes a receptor tyrosine kinase that is essential for normal cell growth and differentiation. Disruption of its function leads to the uncontrolled growth of mast cells. That mastocytosis typically arises from acquired, somatic mutations rather than through a traditional inherited pattern.

Treatment planning for mastocytosis depends on disease stage, tumor characteristics, and overall health, and is optimally managed by a multidisciplinary oncology team. For many individuals, standard supportive care is central to management, with interventions aimed at alleviating symptoms and preventing complications. Currently, an FDA-approved treatment for mastocytosis is available in the form of GASTROCROM (cromolyn sodium), which is used to help manage symptoms. Moreover, several additional therapies are under investigation and clinical trials continue to explore new treatment approaches. Patients should discuss treatment options with their healthcare team and consider genetic counseling for further guidance.

The course of mastocytosis is highly variable, with outcomes that depend on the extent of disease involvement and the organs affected. Some individuals, especially those with primarily cutaneous involvement, may experience a relatively indolent course, while others with systemic disease may face more significant challenges related to organ dysfunction. With current standards of care, many individuals benefit from treatments that improve quality of life. Outcomes described in medical literature continue to evolve as standards of care improve. Families often find it helpful to connect with specialists familiar with this condition and to seek genetic counseling for guidance in family planning.

Mastocytosis is an active area of research with numerous ongoing clinical trials investigating new therapeutic approaches. Individuals interested in clinical trials can search ClinicalTrials.gov or consult their care team about eligibility.