Bilateral Dysplastic Gangliocytoma with Concurrent Polyostotic Fibrous Dysplasia: A Case Report and Literature Review.

Background: Dysplastic gangliocytoma is a sporadic cerebellar benign tumor with the characteristics of hamartoma and true tumor, also known as Lhermitte-Duclos disease (LDD). Bone fibrous dysplasia (FD) is a slowly progressive self-limited benign bone tissue disease. Cowden syndrome, an autosomal dominant genetic disorder caused by germline mutations in the PTEN gene, is considered to be closely related to dysplastic gangliocytoma. McCune-Albright syndrome is a disease characterized by café-au-lait skin macules, polyostotic FD, and precocious puberty. The etiologic mechanism of both conditions is not yet clear. We report a rare case of bilateral dysplastic gangliocytoma with concurrent polyostotic FD.

Case Description: We describe a 16-year-old boy with both LDD and FD. He presented for medical examination with headache and poor eyesight. Magnetic resonance imaging revealed proliferation of the skull and abnormal signals in the cerebellum, and supratentorial hydrocephalus. Subtotal resection of the cerebellar tumor was performed, and the diagnosis of LDD and FD was confirmed by histopathology. No other abnormal changes were found in systemic medical examination and no PTEN gene mutation was found in the genetic analysis; therefore, the diagnoses of Cowden syndrome and McCune-Albright syndrome were excluded.

Conclusions: LDD and FD are 2 rare diseases, and the simultaneous occurrence of the 2 conditions has not been reported before, to our knowledge. Our report challenges the etiology of the 2 diseases and the relationship between them, hoping to provide a reference for the study of the 2 diseases.