“…While the highly atypical cells can histologically mimic other tumors , mast cell tryptase levels, which are frequently markedly elevated, point to the correct diagnosis. Symptoms related to mast cell mediators such as fever, flushing, diarrhea, and tachycardia occur in only one‐third of all cases . These tumors frequently occur de novo in bone, more rarely in the oropharyngeal and gastrointestinal tract, the lymph nodes, skin, liver, spleen, or other organs.…”