Indolent systemic mastocytosis (ISM) is a clonal mast cell disorder requiring hematologic expertise integrated with multidisciplinary collaboration for comprehensive patient management.1 As hematologists increasingly assume central roles in ISM care, understanding the multisystem nature of disease manifestations and coordinating with allergists, dermatologists, gastroenterologists, and other specialists becomes essential for optimal outcomes.1
Diagnostic delays present a challenge in ISM due to heterogeneous clinical presentations, which may include cutaneous mastocytosis with urticaria pigmentosa, recurrent anaphylaxis, refractory gastrointestinal symptoms, or unexplained osteoporosis.1–3 Recent data suggests heightened clinical suspicion is warranted in patients presenting with vertebral osteoporosis in males under 50 years of age, osteoporosis refractory to bisphosphonate therapy, or recurrent episodes of unexplained anaphylaxis.1 Initial evaluation should include serum tryptase measurement, interpreted in the context of potential hereditary alpha-tryptasemia, which affects approximately 5% of the general population.1
Assessment of clinical features such as symptom burden, bone involvement, and serum tryptase levels may help guide diagnostic evaluation, including the use of highly sensitive peripheral blood KITD816V mutation testing.1 While peripheral blood testing using digital droplet polymerase chain reaction (ddPCR) can provide sensitive detection and quantitative assessment of mutant allele burden, bone marrow biopsy remains required to establish a definitive diagnosis and to fully characterize disease extent and classification.2 Definitive diagnosis relies on bone marrow findings demonstrating characteristic mast cell aggregates with aberrant immunophenotypic and molecular features consistent with clonal mast cell disease.1 Collaboration with experienced hematopathologists is critical to ensure accurate diagnosis and classification.
Beyond establishing diagnosis, hematologists play a central role in coordinating longitudinal management focused on symptom control, prevention of complications, and surveillance for disease progression. The availability of tyrosine kinase inhibitors targeting KIT mutations has expanded therapeutic options beyond traditional symptomatic management, necessitating careful assessment of disease burden, symptom severity, and quality-of-life impact when determining treatment approaches.1,4 This expansion in treatment options makes it possible to consider both symptomatic therapies and disease-modifying agents when creating a treatment plan. Establishing structured referral pathways, incorporating validated symptom assessment tools, and maintaining regular interdisciplinary communication are key components of optimized care delivery for patients with this complex and rare disease.
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