FDG PET/CT depicts cutaneous plasmocytoma

Area of Science:

• Oncology
• Dermatology
• Hematology

Background:

• Multiple myeloma (MM) is a plasma cell malignancy.
• Cutaneous involvement in MM is uncommon and associated with poor prognosis.
• IgA-λ subtype and prior autologous stem cell transplantation were noted.

Observation:

• A 63-year-old man with IgA-λ multiple myeloma (MM) presented with multiple violaceous skin lesions.
• Lesions were predominantly located on the trunk and were nontender.

Findings:

• F-FDG PET/CT revealed disseminated, hypermetabolic subcutaneous lesions consistent with active MM.
• Histopathology confirmed λ-restricted plasma cell infiltrates with a high proliferation index (Ki-67 ≈ 80%).

Implications:

• Cutaneous manifestations of MM are uncommon and associated with a poor prognosis.
• Early recognition and diagnosis of skin lesions in MM patients are crucial.