Mature Ovarian Teratoma After Treatment for Unilateral Retinoblastoma With Nonmutated RB1

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To the Editor:
Retinoblastoma is the most common primary eye cancer in children. It accounts for 4% of childhood malignancies with an incidence of 1 in 15,000 to 20,000.1 It presents in 2 forms: hereditary and sporadic. The sporadic form due to somatic mutation is unilateral, but the inherited form due to a germline mutation with subsequent somatic mutation may be either bilateral or unilateral (in up to 30%).2 Hereditary retinoblastoma is strongly associated with the development of secondary primary tumors, especially after treatment with radiation.3 There is a 1% rate of second tumor development per year in patients with germline RB1 mutation. However, the incidence of secondary malignancy is 35% in children who received radiation and only 6% in those who did not.1 The most commonly associated tumors are bone and soft tissue sarcomas with other tumors including skin cancers and central nervous system tumors.4 These secondary malignant tumors represent the most common cause of death in patients with bilateral retinoblastoma.5 In contrast, sporadic retinoblastoma has not been associated with the development of secondary tumors, and patients with unilateral retinoblastoma and subsequent malignancy are usually presumed to have a germline mutation with the less common unilateral phenotype.2 We report a case of a mature ovarian teratoma that developed in a patient previously treated for unilateral retinoblastoma.
A 12-year-old girl with a history of unilateral retinoblastoma in her right eye at 13 months of age presented with abdominal pain. She had been treated with enucleation and a 6-month chemotherapy regimen of vincristine, carboplatin, and etoposide. There was no family history of retinoblastoma. Over the past 2 years, she had experienced several episodes of intermittent abdominal pain lasting 5 minutes. One year before admission, an abdominal ultrasound at another hospital showed no mass or other abnormality. On the date of admission, she experienced sharp pain in the right lower quadrant along with 2 episodes of vomiting and reported to an outside hospital emergency department. An abdominal ultrasound now showed a mixed solid and cystic right adnexal mass measuring 8.4×5.7×8.3 cm in maximal dimensions. An abdominal computed tomographic scan showed a nodular component of the mass containing both calcification and fat. Laboratory studies showed a normal serum alpha fetoprotein (1 ng/mL) and low CA-19-9 (7 units/mL). Upon resection, the mass was found to be fluid-filled with visible debris. A frozen section confirmed the diagnosis of a mature teratoma with cystic and solid elements and no malignant cells. This diagnosis was corroborated by the final pathology, and cytology of peritoneal fluid also revealed no malignant cells. After discharge from the hospital, the patient returned for genetic testing of the RB1 gene using sequence analysis and deletion/duplication testing. The result was negative.
Mature teratomas are the most common ovarian tumor in females under age 20,6 but they are rare as ovarian masses occur with an incidence of 2.2 cases in 100,000.7 Mature teratomas account for about 10% to 20% of those cases.8 Retinoblastoma is relatively uncommon, with an incidence of 1 in 15,000 to 20,000 births.1 There is a case report of a boy who developed a mature testicular teratoma 6 years after he underwent enucleation and chemotherapy for unilateral retinoblastoma.9 Draper et al10 reported that in a series of 217 offspring of retinoblastoma patients 1 child developed a testicular teratoma, and they also noted that the sibling of a patient with unilateral retinoblastoma also developed a testicular teratoma. Considering the rarity of both retinoblastoma and mature teratoma, this information suggests the possibility of an association in their development.
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