Follicular Lymphoma Arising In a Mature Cystic Teratoma in a 26 Year Old Female.

Malignant transformation in mature cystic teratomas is rare and accounts for 0.17-1.4% of cases. Squamous cell carcinoma is the most common malignant tumor in teratomas and accounts for more than 80% of cases. We present the case of a 26-year-old female with no significant past medical history who presented to the ER with abdominal pain. Imaging studies showed an ovarian cyst, which on histological examination showed a mature cystic teratoma with a follicular lymphoma. It is an extremely rare occurrence with only four reported cases in the English literature.