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The following is a summary of “Prevalence Of Osteoporosis Is Low in Adult Cutaneous Mastocytosis Patients,” published in the May 2024 issue of Allergy & Immunology by Degboé, et al.

Systemic mastocytosis (SM) is a clonal disorder of mast cells (MCs) often associated with vertebral osteoporosis (OP) and vertebral fractures (VFs). The natural history of OP in this context is unclear, particularly whether OP is an early event linked to MC abnormalities and if MC clonality alone can cause osteoporosis. For a study, researchers sought to describe osteoporosis in patients with medullary clonality in cutaneous mastocytosis (CM) and monoclonal mast cell activation syndrome (MMAS) and to compare their osteoporosis characteristics with those of nonadvanced patients with SM (bone marrow mastocytosis and indolent systemic mastocytosis).

The retrospective study analyzed clinical, biological, and densitometric data from 27 CM, 13 MMAS, and 135 patients with SM from the Mastocytosis Expert Center (CEREMAST) in Toulouse, France.

Osteoporosis prevalence was 3.7% in CM, 30.8% in MMAS, and 34.1% in SM, while vertebral fractures were observed in 0.0%, 15.4%, and 20% of these groups, respectively. Despite clonal MCs in the bone marrow, patients with CM exhibited lower frequencies of OP and VFs compared to MMAS and patients with SM. Most non-SM patients with OP and VFs had typical osteoporosis risk factors. Notably, the only non-SM patient with typical SM-like OP had elevated bone marrow tryptase, developed a bone marrow KIT mutation during follow-up, and had a family history of SM. These findings indicate that OP is uncommon in CM but prevalent in MMAS. When OP and VFs occur in CM and MMAS, their clinical presentation differs from the typical SM bone fragility phenotype.

In most CM patients, the interpretation and management of osteoporosis differed from those in MMAS and nonadvanced SM. Prospective longitudinal studies and the validation of predictors were necessary to identify CM and MMAS patients at risk of developing SM-related osteoporosis.

Reference: sciencedirect.com/science/article/pii/S2213219824001958