[Case of primary lymphoplasmacytic lymphoma limited to the paratracheal mediastinum].

[waldenström macroglobulinemia]

A 54 year old Japanese man was introduced to Saiseikai General hospital for an evaluation of an abnormal chest X-ray film . Abnormal soft tissue area was observed in the mediastinum surrounding anterior area of the trachea on chest CT . Because the mediastinal tumor showed slow enlargement after temporal decrease and surgical resection of the tumor was performed 3 years after the first visit . Pathologically , diffuse proliferation of oval-shaped plasmacytic or small lymphocytic cells with eccentrically-located nuclei with rough chromatin were observed in the tumor . Immunohistochemically , these cells were positive for CD 2 0 , weakly positive for IgM , negative for CD 3 , CD 5 , CD 10 , suggesting lymphoplasmacytic lymphoma (LPL ). The patient was treated with rituximab after the surgical treatment , and showed no exacerbation for 3 .5 years after surgery . LPL localized to the paratracheal mediastinum is rare , and a surgical approach is important for prompt and proper diagnosis .