The use of chest computed tomography (CT) imaging has demonstrated the ability to identify bronchial or lung lesions in patients with systemic mastocytosis (SM), according to findings from a retrospective, observational study conducted in France and published in the journal Clinical and Translational Allergy.
MastocytosisMastocytosis Rare disease caused by the buildup of mast cells. Cutaneous mastocytosis primarily affects the skin and is more common in children, while systemic mastocytosis affects internal organs and is more common in adults. comprises a heterogeneous group of disorders in which a numerical rise in and accumulation of clonal mast cells are observed in various tissues and organ systems. Among individuals with SM, the severity of the disease ranges from indolent to aggressive. The lungs are recognized as being rich in mast cells, but concomitant respiratory diseases have been suggested as only sporadically being linked to SM.
Recognizing that no data are apparently available on chest CT scans among individuals with SM, the researchers sought to establish the biological and clinical features related to bronchial or pulmonary abnormalities observed on chest CT scans of such patients. They conducted their study between 2003 and 2022 at Toulouse University Hospital Center, located in Toulouse, France.
Study participants included those with a diagnosis of SM obtained from bone marrow biopsyBone marrow biopsy A procedure to collect a sample of bone marrow using a needle. Often used to examine the characteristics of mast cells and diagnose SM. who had a CT chest scan available in their medical record. All of the chest CT images were assessed by two physicians who were blinded to each patient’s functional and clinical specifics.
Read more about SM testing and diagnosis
There were 103 individuals with SM who participated in the study. Overall, 62 participants were female and 41 were male. The median patient age was 54 years old. An elevated risk for a predominant pattern on chest CT imaging was evaluated for aggressive SMAggressive SM A subtype of advanced SM marked by a high mast cell burden that leads to organ damage. Aggressive SM accounts for less than 10% of SM cases. versus indolent SMIndolent SM A subtype of nonadvanced SM caused by the abnormal accumulation of mast cells in the bone marrow and other organs. Indolent SM accounts for around 90% of SM cases., as well as for differing serum tryptaseTryptase A protein enzyme that is primarily produced by mast cells and stored in small pockets within the cells, known as granules. High levels of tryptase are a key indicator of SM. levels.
Indolent SM was reported in 70 participants and aggressive SM in 33 participants. In all, 91 patients had a cKit mutation.
Results of the study revealed a predominant chest CT scan pattern in 35% of the participants. The following lung lesions were observed:
- Nodules: n=11
- Emphysema: n=9
- Bronchiectasis: n=6
- Bronchial wall thickening: n=6
- Interstitial lung disease: n=4
Based on multivariable analysis, an elevated risk for emphysema was reported in those with aggressive SM versus indolent SM. Further, an increased risk for bronchial wall thickening was observed for serum tryptase levels of ≥20 µg/L. No increased risk was identified for all of the other types of lesions.
The investigators noted that respiratory involvement among individuals with SM has not been well described in the literature. Chest CT scans are routinely performed among patients with SM in the Toulouse center, however, researchers stated lung lesions have been observed in approximately 35% of this patient population.
“An increased risk [for] emphysema was observed for aggressive fmastocytosis and bronchial wall thickening for serum tryptase ≥20 µg/[L],” the authors indicated. “A prospective study is required to assess the usefulness of chest CT scan in [patients with] SM.”
