A case report of a patient with an unusual presentation and delayed diagnosis of systemic mastocytosis (SM) has been recently highlighted in a report published in the British Journal of Hematology.
SM is caused by excessive activation of mast cells. These cells secrete chemical mediators that cause noticeable clinical manifestations in multiple organs, such as the skin (rash/urticaria), the respiratory system (shortness of breath), the cardiovascular system (palpitations) and the gastrointestinal tract (diarrhea). Furthermore, it can cause increased organ size, lymph node swelling and bone lesions.
Diagnosis requires a biopsy of the bone marrow or any other affected organ and a genetic study. The genetic study usually shows the presence of mutations in the KIT gene. The presence of mutations in other genes is considered rare, but possible.
Learn more about SM signs and symptoms
The case involved a 50-year-old man who sought medical assistance due to severe, sudden groin pain. Upon examination, the attending physicians discovered a pelvic fracture. Imaging studies of his pelvis revealed weakened, spotty bones. Further interrogation showed a two-year history of intermittent bloating and diarrhea, and a blood cell count revealed decreased platelets and white blood cells.
A biopsy sample taken during endoscopy showed inflammation of the duodenum and increased inflammatory cells; the patient’s bone marrow aspiration showed no abnormalities. A bone marrow biopsy showed scarring (fibrosis). The patient was diagnosed with an abnormality in bone metabolism and discharged.
“Histological findings in the GI tract and bone marrow can be subtle, and a diagnosis may be missed if SM is not specifically considered,” the authors wrote.
Three years later, the patient presented with repeated gastrointestinal symptoms as well as a long-standing rash; an imaging study revealed engrossed lymph nodes in the patient’s thorax, and a further imaging study reported abundant engrossed lymph nodes in the abdomen.
The physicians performed a biopsy of the engrossed lymph nodes and observed several mast cell infiltrates. This, together with immunological analysis, led to the diagnosis of SM.
“Establishing the diagnosis of SM can be challenging and requires a high index of suspicion. In this scenario, the patient presented with sclerotic bone lesions, likely urticaria pigmentosa, lymphadenopathy and diarrheas, but negative bone/bone marrow (within the limits of the sampling), highlighting the importance of adequate tissue sampling when evaluating for SM,” the authors concluded.
