A 58-year-old man presented asymptomatic and with no relevant background. Laboratory tests only showed a slight increase in trypsin levels (19 ng/mL).
The patient presented generalized infiltrative osseous lesions in a radiographic study (Fig. 1).
A CT was performed and revealed the presence of diffuse bone sclerosis interspersed with focal areas of osteopenia and lytic lesions (Fig. 2 and 3).
He underwent a bone marrow biopsy.
Mastocytosis is a heterogeneous group of disorders characterized by the accumulation of MCs in organ systems [1, 2]. The clinical manifestations are caused by the release of biological mediators from MC and/or the destructive infiltration of MC in tissues.
The diagnosis is based on the World Health Organization criteria, which subdivides mastocytosis into seven major categories [3]. Systemic mastocytosis is characterized by involvement of at least one extracutaneous organ, with or without evidence of skin infiltration. Bone marrow is the most commonly involved extracutaneous site and bone marrow aspiration and biopsy are commonly employed to establish the diagnosis [4, 5]. Prognosis is good in patients with indolent forms of the disease.
Mastocytosis
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Based on the provided X-ray and CT images, multiple bony changes are observed, primarily involving the thoracic and lumbar vertebrae, pelvis, and parts of the proximal long bones. On the X-ray, some bone areas may show focal sclerotic lesions or mild lucencies. The CT images indicate altered bone density in regions such as the thoracic vertebrae and pelvis, presenting as patchy irregular enhancements or focal structural abnormalities. No significant fracture lines or severe bone collapse are evident, and no obvious masses or abnormal proliferative signals are noted in the surrounding soft tissues.
Considering the patient’s age, lack of significant symptoms, mildly elevated tryptase levels (19 ng/mL), and the multifocal bone density changes on imaging, the most likely diagnosis is Systemic Mastocytosis (likely an indolent subtype with mild clinical manifestations). A definitive diagnosis often requires bone marrow aspiration or biopsy. If clinically indicated, a bone marrow biopsy or relevant pathological examinations can be performed to confirm the subtype.
Treatment Strategy:
1. If the diagnosis is indolent systemic mastocytosis, management is primarily symptomatic. Medications such as H1/H2 receptor blockers or mast cell stabilizers can be used to reduce discomfort caused by mast cell mediator release.
2. Based on patient status, regular monitoring of serum tryptase and bone condition is recommended. If there are no significant symptoms or disease progression, no specific intervention is required.
3. If progression of bone lesions occurs or if notable symptoms arise (e.g., bone pain, increased fracture risk), low-dose therapeutic interventions or targeted treatments (such as bisphosphonates to improve bone density) may be considered.
4. For a small number of patients with advanced disease, cytoreductive agents or molecular targeted therapies may be considered according to pathological findings and clinical staging; however, such treatments should be used with caution.
Rehabilitation/Exercise Prescription:
• Gradual progression: Given that current symptoms are minimal, low-intensity endurance training is suggested initially, such as brisk walking or light elliptical work, for 15–20 minutes each session, 3–4 times per week. Gradually increase to about 30 minutes.
• Intensity and modality: After adaptation, moderate resistance training (e.g., lightweight dumbbells or resistance bands) may be added. Perform 2–3 sets of 10–12 repetitions each, focusing on lower limbs and core muscles. Avoid high-impact exercises. Moderate intensity is recommended, characterized by mild sweating and a slightly elevated heart rate as a guide.
• Time and frequency: Maintain 3–5 exercise sessions per week. Once bone health is confirmed stable, each session can extend to 30–45 minutes.
• Monitoring and progression: Increase training volume every 2–4 weeks according to bone health and exercise tolerance, and follow up regularly on bone density and blood markers. In the event of bone pain or any discomfort, reassess and adjust the training plan accordingly.
• Safety considerations: For strength or resistance training, it is advisable to use seated or recumbent equipment to avoid heavy loads and high-impact movements (e.g., medium- or high-intensity jumping). Take measures to prevent falls and joint injuries, and consider protective gear during workouts.
Disclaimer: This report is a reference-based medical analysis derived from the available information. It does not replace an in-person consultation or the final opinion of a medical professional. If any questions or changes in condition arise, please seek medical attention promptly.
Mastocytosis
