Gastrointestinal involvement in systemic mastocytosis

Area of Science:

• Gastroenterology
• Hematology
• Oncology

Background:

• Systemic mastocytosis (SM) is a rare disorder characterized by abnormal mast cell proliferation.
• Gastrointestinal (GI) manifestations are common in SM, but their underlying mechanisms are not fully understood.
• Previous studies have focused on serum histamine levels, with inconsistent findings.

Purpose of the Study:

• To investigate the relationship between gastrointestinal symptoms, mast cell infiltration, and histamine levels in patients with systemic mastocytosis.
• To determine whether elevated serum histamine or tissue histamine content is more closely associated with GI pathology in SM.

Main Methods:

• Studied four consecutive patients diagnosed with systemic mastocytosis.
• Performed endoscopy of the stomach and colon, including mucosal biopsies.
• Assessed serum gastrin and histamine levels.
• Measured histamine content in gastric tissue samples.

Main Results:

• All patients exhibited urticaria-like papulae on endoscopy, either spontaneously or after provocation.
• No significant increase in mast cells was observed in mucosal biopsies.
• Serum gastrin and histamine levels were consistently normal across all patients.
• A markedly increased histamine content was found in gastric tissue from three of the four patients.

Conclusions:

• Gastrointestinal symptoms in systemic mastocytosis may be linked to elevated histamine levels within gastric tissue, rather than hyperhistaminemia.
• Urticaria-like lesions observed during endoscopy are a potential indicator of increased tissue histamine.
• Further research is needed to elucidate the precise role of tissue-bound histamine in SM-associated GI dysfunction.