Bone marrow biopsy is absolutely indicated in which of the heamatological conditions?

All of the above options are indications for bone marrow examination. Since bone marrow cannot be aspirated in hairy cell leukemia, bone marrow biopsy becomes an absolute indication for establishing the diagnosis. Ref: Harrison's Principles of Internal Medicine, 16th Edition, Page 652; Davidson's Principles and Practice of Medicine, 20th Edition, Page 1047.