Orbital tumor in an infant with acute monocytic leukemia associated with chromosome 5q-,t(9p-11q+),11p+.

We examined an 8-month-old infant with left proptosis, chemosis and orbital mass. A computed tomographic scan revealed a left orbital tumor. An anorectal nodule was also found. Results of the hematologic study showed poorly differentiated acute monocytic leukemia (M5 according to the French-American-British classification). Chromosomal analysis disclosed 46, XX,5q-,t(9p-;11q+),11p+. We believe that our patient represents a rare case of orbital tumor in acute monocytic leukemia associated with chromosomal abnormalities.