Upon additional clinical history, the patient had a family history of Cowden's syndrome. Craniectomy and tumor resection of the malignant-appearing left temporal mass was performed, revealing a gliosarcoma. No biopsies of the other lesions were performed.

Cowden syndrome:

• Autosomal dominant inherited mutations of PTEN gene.
• Diverse manifestations including breast, endometrial, thyroid, kidney and colorectal cancers, dermatologic features such as oral and skin papillomas, trichilemmomas, and gastrointestinal features such as mixed polyposis including hamartomas, and neurologic features such as Lhermitte–Duclos disease.