Ovarian dermoid cyst with malignant transformation and rupture of the capsule associated with chemical peritonitis: a case report and literature review.

Malignant transformation of ovarian dermoid cysts is rare and spontaneous rupture provoking chemical peritonitis is even rarer. Laparotomy in a 75-year-old Brazilian woman with abdominal pain and signs of peritoneal irritation revealed a voluminous right ovarian cyst with rupture of the capsule, an abundant quantity of fatty material in the abdominal cavity, and signs of peritonitis. Total abdominal hysterectomy and bilateral salpingo-oophorectomy with partial omentectomy were performed. Histopathology confirmed a dermoid cyst with a well-differentiated area of epidermoid carcinoma. The patient refused additional treatment and is currently in the seventh year of follow-up with no signs of recurrence. Rupture of a dermoid cyst of the ovary resulting in chemical peritonitis is very rare and may be associated with malignant transformation.