Infantile pyknocytosis: A rare but not so rare condition. A new case report.

Infantile pyknocytosis is a rare cause of neonatal jaundice associated with transient hemolytic and usually severe anemia, with a favorable outcome. Its etiology remains undetermined. The diagnosis is mainly based on the presence of abnormal erithrocytes (pyknocytes) on the peripheral blood smears. We report the description of a new case recently occurring in a 12-day old caucasian male. The newborn was submitted, together with his parents, to a complete diagnostic process including erithrocytes tests for osmotic resistance, membrane fragility and lysis, and the study of hemoglobin stucture. All the studies resulted compatible with the physiological state of the little patients and his parents. The aim of this paper, is to underline the importance of including this condition among the differential diagnostic hypotheses when dealing with a picture of neonatal hemolytic anemia.