68Ga-PENTIXAFOR PET/CT Captures Superscan in Refractory Multiple Myeloma.

We present a case of a 40-year-old male with refractory multiple myeloma, assessed using 68Gallium-PENTIXAFOR positron emission tomography/computed tomography (68Ga-PENTIXAFOR PET/CT), revealing widespread and intense C-X-C motif chemokine receptor 4 (CXCR4) expression in multiple osteolytic lesions across axial and appendicular skeletons, including bone marrow deposits. Despite undergoing autologous hematopoietic stem cell transplantation and multiple lines of maintenance therapy, the patient experienced disease relapse and progression. The term "superscan" typically refers to diffuse skeletal uptake in conventional bone scans, primarily seen in advanced metastatic cancers or metabolic bone diseases. CXCR4, crucial for tumor growth and metastasis, binds C-X-C motif chemokine 12 (CXCL12) to promote cancer progression. PENTIXAFOR, a CXCR4-targeted PET agent, facilitates imaging of such malignancies. While superscans using PET/CT are rare, our case underscores the utility of 68Ga-PENTIXAFOR PET/CT in evaluating CXCR4 expression in multiple myeloma, highlighting its potential as a diagnostic and prognostic tool in refractory disease management.