Lymphoproliferative disorders associated with carbamazepine. Carbamazepine-induced lymphoproliferative disorders are relatively rare. A 32-year-old woman developed cervical lymphadenopathy while taking carbamazepine. Histologic evaluation of the lymph node biopsy specimen demonstrated near-total effacement of the nodal architecture by a population of pleomorphic immunoblasts. The predominant cell population expressed CD3, CD2, CD5, and CD4, while results of testing for CD8 were negative. On the basis of the morphologic and immunohistologic features, a diagnosis of high-grade, non-Hodgkin's lymphoma, T-cell immunoblastic type, was made. Despite the fact that aggressive behavior is usually associated with immunoblastic lymphomas, the patient has done well for 33 months after cessation of carbamazepine in the absence of chemotherapeutic treatment. The clinical features of this patient's illness, therefore, suggest that it is best regarded as a so-called pseudolymphoma. 