The surgical resection of dysplastic cerebellar gangliocytoma assisted by intraoperative sonography: illustrative case

Abstract

Background: Dysplastic gangliocytoma of the cerebellum (Lhermitte-Duclos disease) is an extremely rare, slow-growing hereditary mass lesion that is mainly characterized by both specific neuroradiological features and secondary hydrocephalus. Patients may present with symptoms of cerebellar mass lesion and increased intracranial pressure. As an important part of Cowden syndrome, Lhermitte-Duclos disease in adults is typically marked by PTEN gene mutation.

Observations: The clinical management of a 31-year-old woman who suffered Lhermitte-Duclos disease was introduced in this case report. Subtotal resection was performed with the assistance of intraoperative sonography to relieve obstructive hydrocephalus, and prophylactic C1 laminectomy was performed to prevent possible postoperative progression of the residual lesion. Perioperative care and surgical process were clearly revealed in an accompanying video. Intraoperative sonography of Lhermitte-Duclos disease presents hyperechoic distorted thickening cortices surrounded by hypoechoic edema belt. The patient did not report any significant neurological complications or sequelae after the lesion resection.

Lessons: The authors first reported the use of intraoperative sonography in resection of adult-onset Lhermitte-Duclos disease. Hopefully, the educative case report can provide a feasible experience in the diagnosis and treatment of Lhermitte-Duclos disease.

Keywords: Cowden syndrome; Lhermitte-Duclos disease; PTEN mutation; dysplastic gangliocytoma of the cerebellum; intraoperative sonography; surgical strategy.

FIG. 1.

Characteristic preoperative MRI in patient with Lhermitte-Duclos disease. In the left cerebellar hemisphere, T2-weighted image (A) revealed a striated feature presenting with the alternating hyper- and hypointense stripes. Diffusion-weighted image (B) shows distinct hyperintensity from the gray matter to the white matter. T1-weighted image (C) appears indistinguishable with hypointensity, whereas slight enhancement is noted after the administration of gadolinium (D). Preoperative MRI presented an uncertain boundary between the lesion and the normal tissue. Both T2 fluid-attenuated inversion recovery (FLAIR) image (E) and T2-weighted image (F) show remarkably bilateral ventricular dilatation, suggesting secondary obstructive hydrocephalus. In T2 FLAIR, the obvious hyperintensity can be easily observed at the frontal horns of the bilateral ventricles, which indicated acute ventricular dilatation (E). The drainage tube of right frontal EVD was noted (arrow) (F).

FIG. 2.

Patient positioning, median suboccipital craniectomy and laminectomy of C1. The patient is in a prone position. The head is flexed and fixed to a Mayfield clamp, leaving a space of about 2 cm between the chin and the chest (A, lateral view; B, superior view). Straight skin incision started 3 cm above the inion and ended at the spinous process of the second cervical vertebra (C2) along the midline (C). The occipital bone and the first cervical vertebra (C2) over the posterior fossa were exposed, and the margin of suboccipital craniotomy was marked with methylene blue (D). The suboccipital craniotomy was completed (E), followed by resection of the posterior C1 arch (F).

FIG. 3.

Intraoperative sonography of patient with Lhermitte-Duclos disease showed an unclearly outlined lesion with alternating strong-poor striped echo (orange arrows) surrounded with hypoechoic edema belt (A, horizontal plane; B, longitudinal plane; green arrows). The residual cavity was confirmed after lesion resection with surrounding hyperechoic hemostatic material (C, horizontal plane).

FIG. 4.

Preoperative and postoperative MRI comparison. Axial T2-weighted images at the ventricular level showed that bilateral ventricular dilation and paraventricular hyperintensity (A) were relieved after lesion resection (D). Axial T2-weighted images at the medipeduncle level showed that most of the lesion was removed (B, preoperative image; E, postoperative image). Coronary section in T2-weighted images showed that secondary tonsillar herniation was cured (C, preoperative image; F, postoperative image).

FIG. 5.

Histopathology of resected lesion and germline mutation in the tumor-suppressor gene PTEN. Grossly, the surgical field presented a distorted and enlarged cerebellar hemisphere with a soft, white appearance and fair blood supply (A). In microscopic view, widened molecular and internal granular layers were filled with irregularly arranged ganglionic cells (B, original magnification ×100; C, original magnification ×200; hematoxylin and eosin staining). Intron 8 mutation c.1026 + 1G > A produces the mutant transcript with intron 8 retention, extending directly from exon 8 sequence (D). The same pathogenic heterozygous mutation was confirmed in both blood sample (a) and tumor sample (b).