CHAPTER 117 Ovarian Lesions Emily Stamell Adekunle O. Oguntayo Evan P. Nadler Introduction Ovarian lesions in paediatric patients require special considerations that may not be applicable in adult patients with comparable diseases. Importantly, these lesions do not follow the same histologic distribution as those seen in adults. They range from benign cysts that can regress spontaneously to bilateral malignancies that require aggressive treatment. Gynecological malignancies account for about 1–2% of all paediatric cancers, and roughly 60–70% of gynecological malignancies are ovarian in origin. 1,2 The diagnosis of ovarian malignancies can often be challeng- ing. Early detection is vital not only for fertility preservation, but also for cure or disease-free remission. Early detection may be even more diffi- cult in developing countries, where access to health care may be limited. Demographics Worldwide and African incidence of ovarian lesions has not been reported; however, the incidence of all ovarian masses in childhood in the United States is approximately 2.6 cases per 100,000 girls per year, and malignancy is reported in 16–55% of cases. 2 In North America, the frequency of ovarian cancer has actually decreased due to the identifica- tion of tumour markers, newer diagnostic imaging modalities, and reclas- sifying the pathology, which allows better identification of all gonadal masses. 3 Laboratory tests for tumour markers and the newer imaging modalities are not readily available or are too expensive to be commonly used in many African regions, however. The frequency of ovarian lesions is greatly influenced by age in North America. Table 117.1 provides the age of peak incidence for ovarian neoplasms in the paediatric population. 4 Tumour Age of peak incidence Mature cystic teratomas >5 years Granulosa cell tumour < 9 years Yolk sac tumours 10–14 years Surface epithelial tumours >10 years Solitary follicle cyst Multiple follicle cyst Large solitary luteinised follicle cyst of pregnancy and puerperium Hyperreactio luteinalis Corpus luteum cyst Pregnancy luteoma Ectopic pregnancy Stromal hyperplasia Stromal hyperthecosis Massive oedema Fibromatosis Endometriosis Cyst, unclassifed Infammatory lesions Table 117.1: Age of peak incidence for common ovarian neoplasms. Aetiology/Pathophysiology Ovarian lesions can arise from different cell types, so the aetiology can vary; however, there is a consistent trend of normal tissue underlying the abnormal lesions. Ovarian cysts arise from mature follicles, and neonatal and prepubertal children have been shown to have active fol- licular growth in the appropriate hormonal millieu. Neoplastic ovarian tumours can arise from germinal epithelium surrounding the urogenital ridge, stromal tissue comprising the urogenital ridge, or germ cells from the yolk sac. The cells dedifferentiate, proliferate, and then undergo malignant transformation. Surface epithelial tumours are more common in women who ovulate more frequently over their lifetime, whereas germ cell tumours are most common in younger children. It is proposed that the more times a follicle ruptures, the more times the ovary epithelium repairs itself, which can increase cellular errors, in turn allowing for increased malignant transformation. This principle may explain why it is believed that pregnancy confers some protection against ovarian cancer, especially in women with high parity. The relevance of this theory in young children is unclear because they either have not begun to ovulate or have ovulated very few times. Sex cord- stromal tumours arise from mesenchymal stem cells below the surface epithelium of the urogenital ridge. These cells have not committed to a cell lineage; therefore, they can differentiate into different cell lines. 5 A number of syndromes are associated with ovarian tumours. Examples include, but are certainly not limited to, Peutz-Jeghers syndrome and granulosa cell tumours, Ollier’s disease and juvenile granulosa cell tumours, Sertoli-Leydig cell tumours, and Maffucci syndrome and fibrosarcoma. 6–8 In nonfamilial cases of ovarian malignancy, infertility and nulliparity have been shown to increase the risk. 8,9 Conversely, multiparity and the use of oral contraceptive pills have been shown to decrease the risk. 10 Other, more controversial, factors that increase the risk of ovarian cancer include the use of ovulation-induction medications and diets that include animal fats, dairy products, and lactose. 5 Genetics have been shown to predispose women to breast and ovarian cancer in roughly 5–10% of patients. The tumour suppressor genes BRCA1 and BRCA2 have been unequivocally linked to ovarian cancer. 11,12 Although other genes are likely responsible for hereditary ovarian cancer, they remain unknown. Pathology The term “ovarian lesion” encompasses a number of nonneoplastic and neoplastic lesions that can be distinguished based on histological features. Tables 117.2 and 117.3 list the nonneoplastic and neoplastic lesions, respectively. The neoplastic lesions comprise both benign and malignant tumours. Nonneoplastic ovarian cysts are included in the spectrum of ovarian lesions because they can produce symptoms mostly related to mass effect and endocrinopathies. 13 Source: Templeman C, Fallat M. Ovarian tumours. In: Grosfeld JL, O’Neill JA Jr, Coran AG, Fonkalsrud EW, Caldamone AA, eds. Pediatric Surgery, Sixth Edition. Mosby Elsevier, 2006, Pp 593–621. Table 117.2: World Health Organization histologic classifcation of nonneoplastic ovarian lesions.