“Dry tap” of Bone Marrow and its Clinical Importance

Objective: Dry tap is usually defined as a “failure to obtain bone marrow on attempted marrow aspiration”. The diagnosis and management of many haematological diseases depends on examination of the bone marrow, which involves two separate specimens i.e. a cytologic and a histologic preparation. The purpose of this study was to document the causes of dry tap and importance of bone marrow biopsy. Design: Descriptive study. Place and duration of study: All reports of simultaneous marrow aspirations and biopsies, performed at the Haematology Department of the Armed Forces Institute of Pathology Rawalpindi between January 1, 2007 and July 1, 2007, were reviewed to determine the frequency of dry taps and the diagnosis and pathologic findings in these cases. Method: A total number of 500 patients were studied. The standard technique was employed in obtaining the samples from posterior superior iliac crest. In the bone marrow examination, aspirate needle was used for bone marrow aspiration and Jamshidi needle (Regular/Adult, 11-gauge) was used for trephine biopsy. All of the procedures for bone examinations were performed unilaterally. Results: Among the 500 studied cases of simultaneous bone marrow aspirations and biopsies, 51 were dry taps (10%). Of these 51 dry taps, only 10 (19.6%) showed normal marrow biopsies, whereas the majority showed significant marrow pathology, usually associated with fibrosis, or hypercellularity, or both. These conditions most likely account for the inability to aspirate marrow. The most frequent diagnoses were acute leukaemia 16 (31.4%), secondary myelofibrosis 3 (5.9%), lymphoproliferative disorder 4 (7.8%), idiopathic myelofibrosis 4 (7.8%), hairy cell leukaemia 2 (3.9%), plasmacytosis 2 (3.9%), secondaries 5 (9.8%), osteoporosis 2 (3.9%) and myeloproliferative disorder 3 (5.9%).