Pediatricians generally have little to do with the way bone marrows (BM) are reported by pathologists. This communication is to emphasize the fact that BM of young children, particularly infants, constitutes a special group, where an active involvement of the pediatrician can ensure correctness of the report.

The BM of infants and young children differs from that of normal adults in having up to 75% (mean + 2 SD) lymphocytes and transitional cells(1). These cells, also called hematogones(2), have morphological features that cause them to be often wrongly interpreted as blasts. This occurs typically in two settings. The first is a BM examination done to look for a hematological or non-hematological malignancy. The second setting is evaluation for remission of a child on therapy for acute lymphoblastic leukemia (ALL). The error here is because of a phenomenon, not very common, known as rebound lymphocytosis, wherein lymphocytes and hematogones come to dominate the BM 6-24 months post-therapy(2,3).

In most of our cases where a mistake had occurred due to rebound lymphocytosis, the follow-up BM examination had been done outside in another hospital and the patient had returned to us after the marrow had been reported as being in relapse. Unfortunately, in all but an occasional of these cases, the pediatrician outside had accepted the wrong diagnosis. Morphological features of the BM cells, however, made it apparent to us that the cells were not blasts and a hematological follow-up resolved the issue.

Preventing such errors is obviously crucial. Providing full clinical information to the pathologist helps, as does firm dependence on ones clinical judgment. However, what would help most, is a high index of suspicion among pediatricians. The greatest problem in this, in our view, is a rather poor awareness because pediatrics texts generally do not discuss BM transitional cells/hematogones(4). Books that do, often do not emphasize these cells in the proper context where it matters most, i.e., in relation to management of hematological and non-hematological malignancies(5). Emphasis of great practical value is present only in a few monographs which are liable not to be consulted by many practicing physicians.

The unique feature of bone marrow of young children and infants and their practical significance therefore needs to be emphasized in the teaching of pediatrics so that pediatricians can interact meaningfully with pathologists in this somewhat difficult area of bone marrow interpretation.

Mona Anand,
V. Thavaraj*,
Unit of Laboratory Oncology,
Institute Rotary Cancer Hospital, and
Division of Pediatric Oncology*,
Department of Pediatrics,
All India Institute of Medical Sciences,
New Delhi 110 029, India.
E-mail : [email protected].

1. Nathan DG, Oski FA. Hematology of Infancy and Childhood, 2nd ed. Phladelphia: WB Saunders Company; 1981. pp 1566-1567.

2. Brunning RD, Mckenna RW. Tumors of the Bone Marrow. Washington DC: Armed Forces Institute of Pathology; 1994. pp 131-133.

3. Dalton Jr W, Stass SA. A morphologic and cytochemical approach to the diagnosis of acute leukemia. In: Stass SA, editior. The Acute Leukemias. Biologic, Diagnostic and Therapeutic Determinants. New York: Marcel Dekker Inc; 1987. p. 79.

4. Mahoney, Jr. DH. Acute lymphoblastic leukemia. In: McMillan JA, De Angelis CD, Feigin RD, Warshaw JB, editors. Oski’s Pediatrics. Principles and Practice. 3rd ed. Philadelphia: Lippincott Williams & Wilkins; 1999. pp. 1493-1501.

5. Handin RI, Lux SE, Stossel TP. Blood. Principles and Practice of Hematology, 2nd ed. Philadelphia: Lippincott Williams and Wilkins; 2002. pp 73 and 744.