[Bilateral breast masses].

A 76 year old woman is hospitalized for bilateral breast masses and neurological impairment. Her medical history is marked by rheumatoid arthritis treated with gold salts and methylprednisolone. Blood tests reveal pancytopenia; the MRI scan of the brain is suggestive of a CNS lymphoma. The pathologic examination of a breast mass specimen confirms the lymphoid nature of the neoplasm. This case report highlights the multifocal or systemic nature of non hodgkin's lymphoma and the diagnostic pitfalls of breast lymphomas. Rheumatoid arthritis and its medical management are reviewed for their possible roles in oncogenesis.