Dysplastic gangliocytoma of the cerebellum (DGC), also called Lhermitte-Duclos disease, is a rare lesion of the posterior fossa consisting of a diffuse hypertrophy of the cerebellar cortex. DGC frequently presents in young adults and rarely in childhood. Only 3 cases have been previously described in newborns. We present an uncommon case of DGC which was diagnosed in utero. The radiological presentation prenatally and at birth was similar to a heterotopic neuroglial brain tissue. MRI aspects evolved from T1/T2 isointense signals to hypoT1 and hyperT2 signals at the age of 1 year. The girl was then operated on total removal of the lesion which was performed with no postoperative complication. Genetics did not demonstrate any germline PTEN mutation or family history suggesting Cowden disease. Two years later, the child was doing well and MRI confirmed complete resection. This case illustrates the difficulties of diagnosing intracranial lesions in foetuses and newborns. Physicians caring for pregnant women and pediatrics should be aware that neoplasm-like lesions such as DGC may present as hamartomas. Surgical resection could then be discussed whenever possible.

小脑发育不良的神经节细胞瘤（DGC），也称为Lhermitte-Duclos病，是后颅窝的罕见病变，由小脑皮质的弥漫性肥大组成。DGC经常出现在年轻人中，很少出现在儿童时期。先前仅描述了3例新生儿。我们介绍了在子宫内诊断出的DGC的罕见病例。产前和出生时的放射学表现类似于异位神经胶质脑组织。MRI方面从1岁时的T1 / T2等强度信号演变为hypoT1和hyperT2信号。然后对女孩进行手术，完全清除病灶，没有术后并发症。遗传学没有显示出任何种系的PTEN突变或家族史，暗示了考登病。两年后，孩子状况良好，MRI证实完全切除。该病例说明了诊断胎儿和新生儿颅内病变的困难。照顾孕妇和儿科的医师应意识到，肿瘤样病变（例如DGC）可能表现为错构瘤。然后，只要可能就可以讨论手术切除。