Unusual Presentation of Giant Leiomyoma with Complete Cystic Degeneration Causing Uniform Uterine Enlargement Corresponding to the 30-week Gravid Uterus in an Adolescent Female

Leiomyomas are benign tumors of monoclonal origin that arise from the smooth muscle of the uterus. The size of leiomyomas varies from microscopic to enormous; “giant” myomas are exceedingly rare. Here, we present an unusual case of a giant leiomyoma with complete cystic degeneration causing uniform uterine enlargement corresponding to the 30-week gravid uterus in an adolescent female. A 19-year-old, unmarried, nulliparous female presented with a history of gradually progressing lower abdominal pain and progressive uniform abdominal distension for 12 months. The mass in the lower abdomen had steadily progressed to the present size, corresponding to that of the 30-week gravid uterus. There was no associated menstrual irregularity, significant medical comorbidity, or family history of malignancies. She underwent laparotomy for the same at a private hospital, where intraoperatively, the origin of the mass was not clear; hence, the tumor was not removed and referred to a higher center. At our institute, she was thoroughly evaluated. Ovarian biomarkers were within normal limits. Contrast-enhanced computed tomography imaging at our institute showed a large mass originating from the pelvis, displacing the abdominal viscera, suggesting a primary ovarian neoplasm. During laparotomy, the uterus was found to be uniformly enlarged to a 30-week gravid uterus size with a smooth surface. A huge cystic tumor of size 35 cm × 25 cm, completely encased in the posterior uterine wall, predominantly in the fundal region just beneath the uterine serosa, was seen. The cyst mass was enucleated from the posterior uterine wall. The dead space was obliterated by posterior uterine wall reconstruction, and the uterus was conserved. The histology and immunohistochemistry revealed a leiomyoma with extensive cystic degeneration. The knowledge of varied clinical manifestations of leiomyomas and the use of better imaging modalities allows to accurately diagnose and meticulous planning for successful outcomes.