Successful stereotactic radiotherapy of meningiomas in a patient with Cowden syndrome: a case report.

Cowden's Syndrome (CS) is a rare disease with increased risk for several carcinomas. Experimental studies and limited case reports have described the negative effects of radiotherapy. A 35-yearold woman presented with newly diagnosed CS and multiple meningiomas. She underwent subtotal resection of a right petroclival meningioma to relieve brainstem compression and received adjuvant fractionated stereotactic radiotherapy 50 Gy in 25 fractions with minimal side effects. Twenty months post-operatively the patient presented with neurological deficits from progression of additional meningiomas. Craniotomy was performed and gross total resection was achieved for all sites of disease. Imaging five months after surgery demonstrated progressive left tentorial meningioma. She underwent definitive stereotactic radiosurgery to 15 Gy and tolerated treatment well. At 32 and 7 months post-RT, the patient has reported no side effects or toxicity as a result of RT, demonstrating for the first time in the literature, to the best of our knowledge, the use of intracranial RT without significant toxicity in CS.