[Systemic mastocytosis with eosinophilia]

Area of Science:

• Hematology
• Cardiology
• Pathology

Background:

• Systemic mastocytosis (SM) is a rare disorder characterized by abnormal mast cell accumulation.
• Eosinophilia, elevated eosinophil counts, can be associated with various conditions, including hematologic malignancies.
• Cardiac complications are a known, albeit less common, manifestation of advanced systemic mastocytosis.

Observation:

• A 67-year-old female with long-standing asymptomatic systemic mastocytosis presented with marked peripheral blood eosinophilia.
• The eosinophilia had progressed to cause symptomatic cardiac insufficiency.
• Despite treatment with prednisone and hydroxyurea to reduce eosinophil counts, cardiac symptoms worsened.

Findings:

• The patient developed atrial flutter and died from pulmonary edema.
• Autopsy revealed fibrotic changes in the heart consistent with end-stage Löeffler's endomyocardial disease.
• The case highlights a severe, fatal cardiac manifestation of eosinophilia secondary to systemic mastocytosis.

Implications:

• This case underscores the critical importance of monitoring for cardiac involvement in patients with systemic mastocytosis and significant eosinophilia.
• It suggests a potential pathway from mast cell activation and eosinophil proliferation to severe myocardial fibrosis.
• Further research into the mechanisms linking systemic mastocytosis, eosinophilia, and cardiac pathology is warranted to improve patient outcomes.