Histopathological trephine biopsy findings in cases of 'dry tap' bone marrow aspirations

Out of 3,173 bone marrow biopsies, we found 138 cases (4.3%) of 'dry tap' aspirations: 35/218 (16%) acute leukemias, 44/445 (9.8%) myeloproliferative syndromes, 29/328 (8.8%) malignant lymphomas and Hodgkin's diseases, 10/208 (4.8%) myelomas and 10/74 (13.5%) metastatic carcinomas. Histology showed that the most common changes associated with scanty yield aspirations were bone marrow fibrosis (patchy or diffuse) and hypercellularity (especially if due to immature cells). None of the 'dry tap' cases showed normal bone marrow by trephine biopsy. It is concluded that the finding of a 'dry tap' should never be dismissed as being due to faulty technique and always needs a bone marrow biopsy.