Unusual presentation of Waldenstrom macroglobulinemia

A 62-year-old Taiwanese man presented to our hospital with soft masses over his right shoulder and left elbow that had rapidly developed over the previous three months. Diagnostic biopsy showed abnormal lymphoplasmacytoid cells in the soft tissue and bone marrow. Serial studies including immunohistochemistry and flow cytometry showed that these abnormal cells strongly expressed cell surface markers such as IgM and CD-20, but not CD3, CD5, or CD10, leading to the diagnosis of Waldenstrom macroglobulinemia (WM). These soft tissue lesions and abnormal cells in the bone marrow decreased gradually after multiple rounds of chemotherapy with R-COP. This study presents a case of WM-a rare B-cell lymphoproliferative disorder-with initial extramedullary soft tissue presentation. Thus, physicians should be aware of this rare soft tissue clinical manifestation in patients.