Cytodiagnosis of Coexistence of Leukemic Infiltration and Extramedullary Hematopoiesis in a Cervical Lymph Node, in T Cell Leukemia Patient.

Extramedullary hematopoiesis (EMH) is a compensatory mechanism that occurs when the marrow is unable to maintain sufficient red cell mass. EMH generally occurs in the patients with deficient bone marrow hematopoiesis secondary to either peripheral red cell destruction or marrow replacement. Although EMH is known to occur in agnogenic myeloid metaplasia with myelofibrosis, chronic myelogenous leukemia, thalassemia, and infiltrative disorders, such as lymphomas, it is rare in acute leukemias. EMH is most commonly seen in the liver and spleen as a diffuse lesion. The involvement of lymph nodes in leukemia and EMH is known; however, to the best of our knowledge, the occurrence of both in the same lymph node has been reported in a single case report. Our case may be the second most rare case of coexistence of infiltration by leukemic lymphoblasts and EMH in the same lymph node detected on FNAC. EMH should be considered in the differential diagnosis of patients with bone marrow disorders and mass lesions in extramedullary sites.