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case_images: Timeline and case progress with relevant data.
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case_images: The timeline of events and case progress with relevant data are presented in  Figure 1 .
case_images: Photographs showing (A) the chronic urticarial rash, (B) facial flushing and (C) profound hypotension during an anaphylaxis episode in our patient (Courtesy of K.T.; written informed consent was obtained from the individual shown).
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case_images: CT scans of the brain (to exclude an intracranial hemorrhage), chest and abdomen (to exclude a dissecting aortic aneurysm) were also unremarkable. Clinical examination revealed mild hepatomegaly and multiple, monomorphic, reddish brown macules of the trunk and extremities ( Figure 2A ). Figure 2B ), tachycardia, lightheadedness and hypotension ( Figure 2C ) in the past, which he could link with emotional stress. Further inquiry about preceding events revealed a fairly consistent pattern of ingestion of certain foods (nuts, legumes, chocolate) or alcoholic beverages, together with emotional stress prior to the onset of the episodes.
case_images: Immunohistochemical staining of bone marrow biopsy showing large clusters of mast cells (red arrows), expressing (A) CD25 and (B) mast cell tryptase. (C) A hematoxylin and eosin (H&E)-stained section of bone marrow core shows areas of paratrabecular fibrosis, in which mast cells can be identified (yellow oval circles).
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case_images: Table 1 ), establishing the diagnosis of SM. The observed mast cells had oval or elongated nuclei and were mostly located around bone marrow trabeculae ( Figure 3C ) and, to a lesser extent, blood vessels. The overall BM cellularity was normal (normal representation of the lymphoid lineage, mild elevation of the erythroid lineage and lower than normal myeloid lineage).