gms | German Medical Science

Objective: During the last few decades, a combination of surgery, chemotherapy and radiotherapy have improved survival rates in the retinoblastoma therapy. Radiation is considered to be one of the factors most strongly associated with an increased risk of meningioma formation. There is a latency period between the radiation exposure and development of meningiomas. It is significantly longer with low- than with high- dose irradiation. Reports on meningiomas following radiation therapy for retinoblastoma are rather scarce. There are no reports in the literature of meningioma development 54 years after the success of unilateral hereditary retinoblastoma’s irradiation. The current case differs from those previously reported in having another histological subtype, hereditary unilateral retinoblastoma and a much longer latency period.

Methods: A 54-year-old woman developed a microcystic angiomatous meningioma in the radiation field 53 years after radiotherapy for the left retinoblastoma. She began to suffer from word finding disorder. Gadolinium- enhanced magnetic resonance imaging (MRI) scan revealed an extra-axial mass lesion in the left mid-cranial fossa, with homogeneous diffuse contrast enhancement and cyst formation.

Results: The lesion was totally removed. The patient’s postoperative course was event-free. The tumor demonstrated positive results for epithelial membrane antigen (EMA) with growth in small bales and small to larger cysts and showed no expression of CD10. The mean proliferation index was under 5%. Four years post surgery the patient remains well without neurological deficits. Repeated MRI scans have revealed no indication of tumor recurrence.

Conclusion: Eleven cases of radiation-induced meningiomas after retinoblastoma therapy have been documented in the literature so far. In our case, the radiation path was centered on the bed of the left enucleated eye and meningioma developed behind the left irradiated orbit 54 years later. Meningotheliomatous, transitional, and fibroblastic histological subtypes are the most common in RIM; however, the histological examination in our case shows a microcystic angiomatous meningioma. The recurrence rates of non-radiation-induced meningiomas are lower than RIMs. Exposure to the potentially carcinogenic effects of radiotherapy should be reserved only for tumors that demonstrate subsequent progression.