The clinical manifestations of systemic mastocytosis (SM) vary greatly from patient to patient, with some presenting back pain as an isolated symptom, according to a recently published case report in JAAPA.
The case involved a 48-year-old man who reported feeling a popping sensation in his back and experiencing strong lower back pain radiating to the right leg after coughing. After a visit to the emergency department, the patient began treatment with hydrocodone/acetaminophen and prednisone.
A few days later, the pain worsened, and the patient visited a family medicine office, where further questioning revealed that he also had generalized itchiness and seasonal allergy symptoms. Additionally, a physical exam revealed a bony prominence in his lower back.
At this point, physicians attributed the pain to a herniated disk and referred the patient to a pain management specialist. The specialist ordered a computed tomography (CT) scan, which revealed two compression fractures in his lower vertebrae. Further testing showed reduced bone density and elevated tryptase levels, prompting suspicion of SM.
The diagnosis was confirmed shortly after through KIT D816V mutation testing and a bone marrow biopsy. After initiating treatment with loratadine for allergy symptoms and zoledronic acid to increase bone density, the patient improved.
Read more about SM testing and diagnosis
Understanding SM’s impact on bone density
Mast cells release several substances, such as interleukins (IL) 1 and 6, which signal bone cells called osteoclasts to increase bone resorption. Increased bone resorption reduces bone density, making bones more fragile. This fragility can lead to pathological fractures.
Pathological fractures are fractures that occur after minor trauma or movements that would not normally cause fractures. In this case, the patient’s coughing appears to have caused a pathological fracture in his vertebrae, leading to back pain.
The authors noted that SM is thought to go undiagnosed in many patients because its complications are incorrectly blamed on other factors and comorbidities. “Due to its heterogeneous clinical presentation — which depends on the organs and tissues involved, the mast cell burden, the presence of comorbidities, and the release of a wide range of chemical mediators — systemic mastocytosis has an unknown true incidence that is likely to be significantly underestimated,” the authors noted.
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