A Case of Acute Promyelocytic Leukemia with Down's Syndrome, with Special Reference to Ultrastructural Observation

Abstract

An 1 9/12-year-old girl with Down's syndrome was admitted because of fever, anemia, bleeding tendency and hepatosplenomegaly. Promyelocytes were predominant in circulating blood and especially in bone marrow. Her clinical course was characterized by rapid dowhill course against treatments, marked bleeding tendency with hypofibrinogenemia and little acceleration of erythrocyte sedimentation rates. She was diagnosed as acute promyelocytic leukemia with Down's syndrome.
Ultrastructual findings of promyelocytes were as follows;
1. The cytoplasm had enlarged granular endoplasmic reticulum, which contained materials with positive peroxidase activities, Showing reticular appearance, partially sack-like or irregularly lamellar structure.
2. There were two types of granules, large and small ones, found mostly around a Golgi apparatus. The large granules revealed positive peroxidase activities and the small ones negative activities. The similar structure to Auer's body was demonstrated in some of the large granules.