Asymptomatic 64-year-old male patient. Routine chest X-ray is performed.
Chest X-ray shows diffuse sclerosis of the humerus, ribs and thoracic vertebrae (Fig. 1). On the abdominal X-ray diffuse sclerosis of the lumbar vertebrae, sacrum, iliac and femoral heads could also be noted (Fig. 2).
Thoraco-abdomino-pelvic CT was then performed and the findings already seen at the plain radiographic films were confirmed (Fig. 3-4).
Bone biopsy confirmed the diagnosis of systemic mastocytosis (Fig. 5).
Mastocytosis is a myeloid neoplastic disease characterized by abnormal mast cell proliferation. Two major forms of this disease have been described: cutaneous mastocytosis and systemic mastocytosis (SM), which is further subdivided in four subtypes; (1) indolent SM, (2) SM associated with non-mast cell clonal haematological disease, (3) aggressive SM, and finally (4) mast cell leukaemia [1].
Clinical manifestations of SM may include anaemia, abdominal pain, diarrhoea, nausea, pruritus and cutaneous flushing. On physical examination hepatomegaly, splenomegaly and lymphadenopathy may also be present.
The major diagnostic criterion for SM is the presence of dense infiltrates of mast cells in the bone marrow. Measurement of serum tryptase is also useful for the diagnosis, with values higher than 11.5 ng/mL found in more than 50% of the cases [2].
Although mastocytosis is mainly a clinical and laboratory diagnosis, it is important to recognize the radiographic features as radiologists may be the first suggesting the diagnosis.
Skeletal involvement is common. Bone abnormalities may be lytic, sclerotic or mixed, usually diffuse sclerotic involvement being the most commonly found. [3] The differential diagnosis of diffuse bone sclerosis is broad and includes fluorosis, haematological causes such as myelofibrosis, sclerosing bone dysplasias as osteopetrosis and pycnodysostosis and neoplastic causes as diffuse lymphoma, prostate or breast cancer metastases. Common abdominal imaging findings are quite nonspecific and include hepatosplenomegaly, retroperitoneal adenopathy, periportal adenopathy, mesenteric adenopathy and omental thickening.
The prognosis of mastocytosis is variable. Patients with cutaneous mastocytosis and indolent systemic mastocytosis remain stable for many years while patients with aggressive SM or mast cell leukaemia progress rapidly, usually with a fatal outcome. [4]
Systemic mastocytosis
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1. From the chest X-ray (Figure 1), no obvious parenchymal lesions are observed in the lung fields, and the cardiac silhouette and mediastinal structures are essentially normal.
2. The lumbar-abdominal radiograph (Figure 2) and subsequent abdominal CT (Figures 3, 4) suggest diffuse sclerosis (increased density) in the vertebrae, pelvis, and bilateral iliac bones, with no significant osteolytic fractures or large focal soft tissue masses.
3. Some images show vertebral bodies with relatively normal morphology but markedly increased bone density.
4. Pathology (immunohistochemistry) (Figure 5) shows a dense distribution of mast cells, consistent with the high clinical suspicion of systemic mastocytosis.
Based on the diffuse bone sclerosis indicated by the imaging, along with clinical and serological findings, the following possibilities are considered:
Considering the diffuse bone sclerosis on skeletal imaging, elevated serum tryptase levels, and mast cell infiltration in the bone marrow or tissue biopsy (regardless of minor discrepancies in the patient’s history regarding sex and age, actual clinical test results are referenced here), the most likely diagnosis is Systemic Mastocytosis (SM).
To further determine the specific subtype (e.g., indolent SM or aggressive SM), more clinical data, complete blood counts, bone marrow biopsy, and genetic testing are needed for comprehensive evaluation.
(1) Medication:
- For mild or indolent systemic mastocytosis, use H1 and H2 receptor antagonists or mast cell membrane stabilizers (such as ketotifen) for symptomatic relief;
- For diarrhea, pruritus, and flushing, antihistamines or leukotriene inhibitors may be prescribed;
- In aggressive cases or those with concomitant hematologic malignancies, tyrosine kinase inhibitors (e.g., midostaurin) or chemotherapy may be necessary to control tumor burden.
(2) Supportive and Symptomatic Treatment:
- Monitor for potential anemia, bone damage, and nutritional issues;
- Regularly check the liver, spleen, and lymph nodes to prevent progressive organ enlargement;
- Consider bone marrow transplantation or targeted therapy if necessary.
Given the bone sclerosis and potential changes in bone quality, high-impact or high-fall-risk activities should be avoided. It is recommended to follow a gradual, individualized approach:
This report is a reference analysis based on the provided medical record and imaging data and does not replace face-to-face diagnosis or a professional physician’s direct advice. If you have any questions or notice any changes in symptoms, please seek medical attention promptly to receive appropriate guidance.
Systemic mastocytosis
