A unilateral functioning uterine anlage with Müllerian duct agenesis

The case reports of two female adolescents with congenital absence of the Müllerian ducts and a unilaterally enlarged uterine anlage containing functioning endometrial tissue are presented. The clinical manifestations may vary depending upon the delay in diagnosis after the onset of endometrial shedding within the anlage. A high index of suspicion and proper diagnostic evaluation may prevent unnecessary hospitalization. In our experience, prompt removal of the functioning uterine anlage affords complete relief of the symptoms.