Distribution of Sclerotic Skin Lesions in Multiple Myeloma
Direct Answer
Sclerotic skin lesions in multiple myeloma are not a typical manifestation of the disease itself; when scleroderma-like skin changes occur with multiple myeloma, they present as scattered morphea-like plaques distributed across the whole body, often with brownish pigmentation, and may include sclerodactyly-like changes affecting the fingers. 1
Clinical Presentation Pattern
The distribution of sclerotic skin lesions when they occur with multiple myeloma includes:
- Widespread body involvement: Morphea-like plaques scattered diffusely across the entire body surface 1
- Pigmentary changes: Brownish pigmentation accompanying the sclerotic plaques 1
- Acral involvement: Sclerodactylia-like changes with contracture of the fingers 1
- Progressive thickening: Gradual progression of skin thickening affecting large body surface areas 2
Critical Context: This is an Extremely Rare Association
The coexistence of scleroderma with multiple myeloma is exceptionally uncommon, with only 13 cases reported in the literature as of 2013. 2 This is not a standard manifestation of multiple myeloma and should prompt consideration of:
- Paraneoplastic phenomenon: Abnormal immunological reactions related to multiple myeloma may cause scleroderma-like lesions 1
- Coincidental occurrence: The association may represent two separate disease processes occurring simultaneously 2
Important Distinction: Osteosclerotic vs. Skin Sclerotic Lesions
You must differentiate between:
- Osteosclerotic myeloma: A variant characterized by sclerotic bone lesions (not skin lesions), which can present with diffuse bone sclerosis or mixed sclerotic and lytic skeletal lesions 3
- POEMS syndrome: Osteosclerotic myeloma associated with polyneuropathy, organomegaly, endocrinopathy, M protein, and skin changes (not specifically sclerotic lesions) 4
- Scleroderma with myeloma: The rare entity described above with actual sclerotic skin lesions 2, 1
Diagnostic Approach When Encountered
- Skin biopsy: Histopathology should confirm scleroderma pattern in the sclerotic skin lesions 2, 1
- Bone marrow examination: Required to document plasma cell dyscrasia with interstitial and focal increase in plasma cells 2
- Serum protein studies: M-protein detection (typically IgG or IgA with kappa or lambda light chains) 2, 1
- Skeletal survey: May show osteopenia without osteolytic lesions in cases with skin involvement, contrasting with typical multiple myeloma 2