FDG-PET/CT findings in systemic mastocytosis: a French multicentre study

Area of Science:

• Hematology
• Nuclear Medicine
• Oncology

Background:

• Mastocytosis is a rare clonal disorder involving mast cell proliferation and activation.
• The diagnostic and prognostic utility of FDG-PET/CT in mastocytosis remains unclear.

Purpose of the Study:

• To evaluate the role of FDG-PET/CT in diagnosing and assessing systemic mastocytosis (SM).
• To compare FDG-PET/CT findings with clinical and biological data in various SM subtypes.

Main Methods:

• Retrospective analysis of 19 adult patients with systemic mastocytosis (SM).
• Patients underwent FDG-PET/CT imaging.
• Semi-quantitative and visual analysis of FDG uptake was correlated with clinico-biological data.

Main Results:

• FDG uptake was noted in bone marrow, lymph nodes, and spleen, but not significantly in smouldering SM or aggressive SM.
• Pathological FDG uptake was observed in bone marrow and lymph nodes of patients with SM-AHNMD.
• Mast cell sarcoma (MCS) patients showed intense bone marrow uptake, mimicking metastases.
• No correlation found between FDG-PET findings and serum tryptase, mast cell infiltration, or CD30/CD2 expression.

Conclusions:

• FDG-PET/CT is not a sensitive marker for mast cell activation in common SM forms.
• FDG-PET/CT may be valuable for early identification and therapeutic assessment in SM-AHNMD and MCS.
• Further research is needed to define the precise role of FDG-PET/CT in specific mastocytosis subtypes.