Systemic Mastocytosis Differential Diagnoses

Updated: May 30, 2023
  • Author: Devapiran Jaishankar, MBBS; Chief Editor: Emmanuel C Besa, MD  more...
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Diagnostic Considerations

The three most important conditions in the differential diagnosis are carcinoid syndrome, VIPoma, and Zollinger-Ellison syndrome. Like systemic mastocytosis (systemic mast cell disease), each of these conditions causes diarrhea, abdominal pain, and some degree of malabsorption.

Urticaria pigmentosa can help distinguish systemic mastocytosis from the other disorders. Plasma hormone measurements can also help in identifying these disorders: Gastrin levels can be elevated in persons with Zollinger-Ellison syndrome, and serotonin levels can be elevated in persons with carcinoid syndrome. Other malabsorption syndromes, such as celiac sprue, are also in the differential diagnosis.

Three other disorders of mast cell activation with overlapping clinical and pathological features are monoclonal mast cell activation syndrome, idiopathic mast cell activation syndrome, and idiopathic anaphylaxis. Systemic mastocytosis is a histopathologic and genetic diagnosis and should not be based solely on clinical presentation. 

Bone marrow involvement can have a differential diagnosis that includes primary myelofibrosis, reactive mastocytosis, and other myeloproliferative disorders, especially chronic eosinophilic leukemia.  These disorders can be distinguished from systemic mastocytosis by differences on bone marrow biopsy as well as the presence or absence of characteristic clinical and laboratory features. Distinguishing lymph node involvement from a wide variety of lymphomas is based on histomorphology and staining. However, clinicians should remain aware that systemic mastocytosis can coexist with other primary hematologic disorders.

Differential Diagnoses