朗读老师：王芳 东莞人民医院
翻译老师：王会 浙江省立同德医院
审校老师：姜春雷 青岛市第九人民医院
History: Young man with precocious puberty as a child.
病史：青年男性，童年时性早熟。
An MRI of the brain was obtained. Selected images are submitted below. CLICK ANY IMAGE TO ENLARGE IT.
Annotated images are available for your convenience while you review the findings below. CLICK ANY IMAGE TO ENLARGE IT.
Findings: MRI demonstrates a T1 and T2 isointense mass lesion in the region of the tuber cinereum of the hypothalamus, measuring approximately 3cm X 1.5cm X 2cm. The lesion is nonenhancing.
Differential Diagnosis (given clinical history and radiologic appearance):
Hamartoma of the tuber cinereum most likely
Diagnosis: Hamartoma of the Tuber Cinereum
影像表现：MRI示下丘脑灰结节区T1、T2等信号肿块，大小约3cm×1.5cm×2cm，病灶无强化。
鉴别诊断（结合临床及影像表现）：最可能为灰结节错构瘤
诊断：灰结节错构瘤
Clinical:
Hamartoma of the tuber cinereum is a rare malformation usually discovered during a work-up for precocious puberty or seizures. They are congenital, non-neoplastic heterotopias. The tuber cinereum is a region of the posterior hypothalamus located between the infundibular stalk and the large prominent mammillary bodies. The lesions may be sessile or pedunculated. Histologically, the hamartoma closely resembles gray matter and some of the neurons may resemble hypothalamic tissue. Children may present with precocious puberty although the mechanism by which this occurs has not been defined. One hypothesis suggests that there is interruption of the inhibitory neuronal pathways from the hypothalamus to the posterior pituitary from mechanical compression by the mass. This can also occur with hypothalamic gliomas. Seizures have been reported in patients with larger lesions. Gelastic epilepsy, resulting in spasmodic laughter with onset in infancy, is exceedingly rare but has been reported to occur in patients with hamartomas of the tuber cinereum. The lesions may be pedunculated or sessile. Patients who present with precocious puberty have pedunculated masses that extend into the suprasellar and prepontine cisterns. Patients presenting with seizures have tend to have sessile lesions. Associated congenital anomalies with midline hamartomas have been reported and include: callosal agenesis, optic malformation, and hemispheric dysgenesis.
灰结节错构瘤
临床：灰结节错构瘤是一种罕见的畸形，通常由于性早熟或癫痫发作发现。为先天性非肿瘤性异位。灰结节是下丘脑后部的一个区域，位于垂体柄和乳头体之间。病变可无蒂或有蒂。组织学上，错构瘤与灰质极为相似，部分神经元与下丘脑组织相似。儿童可能会出现青春期早熟现象，尽管其机制尚未明确。一种假说认为，由于肿块的机械压迫，可导致下丘脑到垂体后叶的抑制性神经元通路中断。下丘脑胶质瘤也会出现这种情况。据报道，病变较大者可出现癫痫。痴笑样癫痫表现为痉挛性发笑，婴儿期发病，非常罕见，有报道发生于灰结节错构瘤患者。病变可有蒂或无蒂。表现为性早熟的患者为带蒂的肿块，可延伸至鞍上和桥前池。癫痫发作型病人往往为无蒂广基底肿块。已报道与中线错构瘤相关的先天性异常包括：胼胝体发育不全、视神经畸形和半球发育不良。
Making the diagnosis:
In children presenting with precocious puberty or seizures, masses of the third ventricle with MRI signal characteristics suggestive of gray matter a diagnosis of tuber cinereum hamartoma can frequently be made based on the imaging. LHRH stimulation test may suggest a central etiology of precocious puberty.
诊断：青春期性早熟或癫痫发作的儿童中，三脑室肿块伴灰质信号特征提示灰结节错构瘤，常可根据影像诊断灰结节错构瘤。LHRH刺激试验可能提示性早熟的主要病因。
Radiology:
On enhanced CT,the hamartoma will appear as an isointense, non-enhancing mass lesion with in the suprasellar region. On MRI studies these lesions are characteristically smooth, well-defined mass lesions. They do not exert mass effect on the surrounding structures. They are characteristically isointense to gray matter on both T1 and T2 images. While hamartomas are T1 isointense and are non-enhancing, hypothalamic gliomas and craniopharyngioma tend to exhibit hypointensity on T1 with enhancement. Although characteristically isointense on T2, some hamartomas have been shown to have increased signal on T2 images which makes distinguishing between hamartoma and low grade glioma difficult.
影像表现：增强CT上错构瘤表现为鞍上等密度、无强化的肿块影。MRI上，典型者表现为光滑、边界清楚的肿块。对周围结构无明显占位效应。在T1、T2图像上与灰质等信号。错构瘤T1呈等信号、无强化，下丘脑胶质瘤和颅咽管瘤T1呈低信号、伴强化。尽管典型者在T2图像上呈等信号，但一些错构瘤表现为高信号，这使得鉴别错构瘤和低级别胶质瘤变得困难。
Pearls:
Hamartoma of the tuber cinereum is a congenital, non-neoplastic heterotopia usually discovered in patients with a clinical history of precocious puberty or gelastic seizures.
Differential includes low grade hypothalamic glioma or solid craniopharyngioma.
On MR: isointense and non-enhancing on T1 with isointensity to hyperintensity to gray matter on T2.
重点：
1、灰结节错构瘤是一种先天性的非肿瘤性异位，通常伴有青春期早熟或癫痫。
2、鉴别诊断包括下丘脑低级别胶质瘤或实性颅咽管瘤。
3、MRI：T1上呈等信号、无强化，T2上呈等-高信号。
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