[Neonatal monoblastic leukemia revealed by transitory specific skin lesions]

Specific cutaneous involvement is frequently observed in congenital leukemia and may be the inaugural sign. Lesions may be non-specific and even regress spontaneously, misleading diagnosis and delaying care.

A infant in good health had diffuse ecchymotic maculae at birth which totally regressed within 10 days. On day 20, a macular rash and three violet nodules developed. The physical examination found enlarged nodes, liver enlargement and poor general status. Blood cell counts and the myelogram led to the diagnosis of type 5 acute myeloblastic leukemia (AML 5). Search for extension revealed cutaneous leukemia and meningeal and renal involvement.

The predominance of myelocyte forms is specific for neonatal leukemia (AML 5 and 4). Specific skin lesions are frequent (25 to 30 p. 100 of cases) and sometimes precede (7 p. 100) anomalies in peripheral and medullary smears. Skin biopsy with direct smear can provide rapid diagnosis. Classically subcutaneous nodules or bluish macropapulae give the blueberry muffin baby aspect. The polymorphous features and the remarkably fluctuating skin lesions in our case are unusual, especially since the infant did not have spontaneously reversible neonatal leukemia, a rare unpredictable phenomenon described in newborns with a normal phenotype which can mislead therapeutic management.