Cutaneous Involvement in Waldenström's Macroglobulinaemia.

Area of Science:

• Hematology
• Dermatology
• Oncology

Background:

• Cutaneous involvement in Waldenström's macroglobulinaemia (WM) is not well-defined.
• Understanding skin manifestations is vital for diagnosis and prognosis.

Purpose of the Study:

• To characterize cutaneous involvement in WM.
• To differentiate between non-transformed and transformed cutaneous B-cell tumors in WM.

Main Methods:

• Retrospective study of 19 WM patients with cutaneous involvement.
• Analysis of clinical, histological, and immunohistochemical features.
• MYD88 L265P mutation testing on skin biopsies.

Main Results:

• Group 1 (non-transformed): 12 patients, predominantly infiltrated plaques, inaugural in 6, MYD88 L265P mutation detected in all tested, 3-year survival 88%.
• Group 2 (transformed): 7 patients, ulcerated tumors on trunk/limbs, transformation during follow-up in 71%, 3-year survival 22%.
• Distinctive clinical, histological, and molecular characteristics observed.

Conclusions:

• Cutaneous WM has unique clinical and histological presentations.
• The MYD88 L265P mutation is prevalent in non-transformed cutaneous WM.
• Distinguishing between non-transformed and transformed lesions impacts prognosis significantly.