The morphological subcategories of acute monocytic leukemia (M5a and M5b) share similar immunophenotypic and cytogenetic features and clinical outcomes.

Acute monocytic leukemia (M5) is a subtype of acute myeloid leukemia (AML) with two distinct morphologic subcategories, M5a and M5b. We compared the immunophenotype, cytogenetics and clinical outcome of AML M5 with non-M5 AML and also compared M5a with M5b. One hundred and twelve M5 (76 M5a, 36 M5b) and 726 non-M5 cases were identified and treated on protocols at our institution. There were no significant differences in immunophenotype between M5a and M5b. Translocation 11q23 was the sole abnormality in 18.6% of M5 and 3.2% of non-M5 (p<0.001). Trisomy 8 was also more prevalent in M5 (16.9%) than in non-M5 (8.7%; p=0.03). There was no significant difference in karyotypes between M5a and M5b. The complete remission rate was 70% for AML M5 and 57% for non-M5 AML (p=0.03). There was no significant difference in median overall survival or disease free survival for patients with M5 versus non-M5, M5a versus M5b. Our data indicate that the prognosis of AML M5 is similar to non-M5 AML and that M5a and M5b do not differ in immunophenotype, cytogenetics or clinical outcome.

Association between Breus' mole and partial hydatidiform mole: chance or can hydropic villi precipitate placental massive subchorionic thrombosis?

Breus' mole (massive subchorionic hematoma) is a rare entity most often found in the placentae of macerated stillborn fetuses. Previously considered to represent a postmortem event, recent evidence suggests that it occurs prior to fetal demise. A 23-week gestation male neonate was delivered of a 23-year-old gravida 3, para 2 woman and survived for 49 min. An autopsy with chromosomal studies resulted in a diagnosis of triploidy. Placental examination showed the presence of both Breus' mole and also partial hydatidiform mole. DNA samples extracted from portions of the fresh hematoma and from the fetal spleen were compared using molecular techniques. PCR analysis showed the presence of Y chromosome specific DNA in the placental clot, but a semiquantitative Southern blot demonstrated that roughly 85% of the clot DNA was of maternal origin. These findings suggest that Breus' mole represents primarily maternal thrombosis rather than fetal hemorrhage. We hypothesize that the partial mole could have contributed to the formation of the Breus' mole as some of the hydropic villi may have focally obstructed the maternal venous return from the intervillus space causing sluggish flow and promoting thrombosis. A review of the literature on Breus' mole shows that the majority of reported cases have not included cytogenetic findings. However, several authors have reported an association with triploidy and other chromosomal anomalies characterized by scattered placental hydropic villi. Thus, we suggest that obstruction of maternal venous return by hydropic villi may have played a contributory role in some of these other reported cases.