The word teratoma is derived from the Greek word
teraton, meaning monster, and was used initially by Virchow in the first edition of his book on tumours, which was published in 1863 (see [
2]). Since mature cystic teratomas are composed of all three germ cell layers, the term 'dermoid' is a misnomer. Mature cystic teratomas are thought to arise from primordial germ cells. This theory is supported by the distribution of these tumours along the lines of migration from the yolk sac to the primitive gonad. The majority of these tumours occur during the reproductive years providing further support for the germ cell theory [
2]. Benign cystic teratoma (BCT) is the most common benign ovarian neoplasm comprising 10–15% of all ovarian tumours. It occurs at all stages of life, the majority of cases being diagnosed between 20 and 30 years of age [
4]. This fact makes it the most common tumour during pregnancy (22–40% of all ovarian tumours) [
4]. In pregnancy the risk of complications increases significantly including rupture, torsion, infection and malignant degeneration. As BCT has a tendency to remain in the confines of the true pelvis, it could lead to dystocia and obstructed labour [
4]. Treatment is surgical removal as soon as possible after diagnosis to avoid complications. Ovarian cystectomies or oophorectomies via laparoscopy or laparotomy are options depending on the situation and expertise available. All efforts should be made to avoid rupture or leakage of cyst fluid during the operation. If it happens before or during the operation, copious saline washing should be performed to minimise chemical peritonitis and its sequelae [
3,
7,
8]. When BCT is found incidentally in the first trimester of pregnancy, surgical removal should be performed at 14–16 weeks of gestation to avoid the risk of damage to the corpus luteum. If diagnosis of BCT occurs at 16–22 weeks, surgery should be performed as soon as possible. If it is first discovered after 22 weeks of pregnancy, the treatment may be deferred until delivery [
4]. Over 200 cases of BCT in pregnancy have been reported in the literature and many of them ruptured spontaneously or iatrogenically. In a review of 47 cases, Kocak et al [
9] reported that during cyst extraction, minimal spillage occurred in 42.5% of cases and none developed chemical peritonitis.
Clement et al [
7] and Achtari et al [
8] reported chemical peritonitis following cystic fluid spillage. The patients needed further surgeries to treat the complications. Two other case reports by Suprasert et al [
4] and one by Phupong et al [
5] reported a diffuse peritoneal reaction mimicking advanced ovarian malignancy where full surgical staging was performed. Postoperative histological examination revealed BCT and chronic granulomatous peritonitis. A conservative approach was adopted and patients were free of symptoms without further treatment at 12 months [
1,
5]. The incidence of chemical peritonitis after rupture and leakage of cystic fluid in the peritoneum is less than 0.5% (see [
2]). The incidence of chronic granulomatous peritonitis after rupture or leakage of cystic fluid is also extremely rare. In granulomatous peritonitis after ruptured ovarian teratomas, numerous nodules of mature glial tissue implant on a widespread area of the peritoneum [
10].
Ruptured BCT of the ovary mimicking gynaecological malignancy is uncommon and could be misdiagnosed [
5]. Intra-abdominal peritoneal seedlings, adhesions and/or masses are frequent sequelae. In most such cases, abdominal seedlings are essentially of mature neuroglial elements and long-term survival rate is good. Recognition of a dermoid tumour associated with glial seedling is important to avoid unnecessary debulking surgery. Following postoperative adhesions, fibrous bands or obstructions, conservative management seems to have a good prognosis.