Figure 4: Schematic presentation of enlargement of the inclusion cyst. (a) At 9 weeks, the right mucinous cystadenoma and left cyst (later diagnosed as an inclusion cyst) existed independently. (b) During gestation progressing, the inclusion cyst became larger. The right ovarian cyst and inclusion cyst became close. (c) Finally, the right ovarian cyst was involved in the inclusion cyst. Mucin-producing cells were observed mainly on the near-side of the right ovarian cyst. The wall of the inclusion cyst was largely destroyed due to inflammation, which made it difficult to conduct a detailed histological examination such as the confirmation of mesothelial cells in the inclusion cyst wall.