Final answer:
In acute monocytic leukemia, besides the infiltration of the gums, a common characteristic feature is the enlargement of the spleen.
Step-by-step explanation:
In acute monocytic leukemia, a characteristic feature commonly seen in addition to the infiltration of blasts in the gums is an enlargement of the spleen. This condition leads to an overproduction of young, immature leukocytes, which results in an impairment of normal blood cell function. Acute monocytic leukemia can also show infiltration of leukemic cells into other tissues, such as the liver and lungs, but splenomegaly, or spleen enlargement, is a particularly notable feature.