Incidentally Detected Transient Abnormal Myelopoeisis in a Placenta of Mosaic Down's Syndrome: A Case Report Describing Approach to Diagnosis.

Examination of the placenta is the easiest and the most cost-effective method to evaluate fetal abnormalities which might be missed by other antenatal screening techniques. Transient abnormal myelopoeisis (TAM) in placenta is one such condition which is specific for trisomy 21. Its relevance especially lies in cases where phenotypical features of down's syndrome are absent in fetus or the cytogenetic reports are negative, suggesting either confined placental mosaicism or low expression generalized mosaicism. This is imperative in parents' counseling and deciding further patient management because though TAM is a transient phenomenon, it may relapse or progress to acute leukemia.