A case report highlighting systemic mastocytosis (SM) as a possible cause of chronic diarrhea was recently published in Clinical Endoscopy.
Although many SM cases present with a combination of recognizable features such as diarrhea, flushing, itching and anaphylaxis, some patients present with a single symptom, which can complicate diagnosis. The following case illustrates one such presentation.
The case involved a 64-year-old man who sought medical attention due to chronic diarrhea that had persisted for two months, resulting in a weight loss of approximately 22 pounds (10 kilograms).
Physical examination on admission revealed multiple dark spots on his skin and enlarged lymph nodes.
Laboratory workup showed leukocytosis, thrombocytopenia and acute kidney injury secondary to dehydration. Physicians investigated potential infectious causes, but viral, bacterial and parasitic testing all returned negative. A computed tomography (CT) scan of his abdomen revealed an enlarged liver and spleen (called hepatosplenomegaly).
To rule out hematologic malignancy, the medical team performed a bone marrow biopsy, which revealed nonspecific immune cell proliferation. A subsequent gastroscopy showed findings suggestive of gastritris (inflammation of the stomach lining), and a colonoscopic biopsy showed spindle-shaped eosinophilic infiltrates suggestive of a mast cell disorder. Further testing (including immunohistochemistry) confirmed the diagnosis of aggressive SM.
Read more about SM testing and diagnosis
In SM, mast cells infiltrating the intestinal wall can release cytokines and other mediators which alter the normal motility of the gastrointestinal tract. This leads to diarrhea, constipation and abdominal pain. Furthermore, the same mediators can alter acid secretion in the stomach, producing gastritis.
The patient began treatment with imatinib; however, due to an unsatisfactory therapeutic response, he was referred for supportive care.
The authors noted that the case highlights the importance of considering SM in patients with chronic diarrhea who have other signs of the disease. “As most symptoms are non-specific, gastrointestinal involvement in SM should be suspected in patients with chronic diarrhea accompanied by typical skin lesions, hepatosplenomegaly, lymphadenopathy, or hematological abnormalities,” the authors concluded.
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