DataSheet_1_Case Report: Lipoma of the Tuber Cinereum Mimicking a Pituitary Gland Abnormality in a Girl With Central Precocious Puberty.pdf

IntroductionMagnetic Resonance Imaging (MRI) is the best approach to investigate the hypothalamic-pituitary region in children with central precocious puberty (CPP). Routine scanning is controversial in girls aged 6-8 year, due to the overwhelming prevalence of idiopathic forms and unrelated incidentalomas. Cerebral lipomas are rare and accidental findings, not usually expected in CPP. We report a girl with CPP and an unusually shaped posterior pituitary gland on SE-T1w sequences.
Case DescriptionA 7.3-year-old female was referred for breast development started at age 7. Her past medical history and physical examination were unremarkable, apart from the Tanner stage 2 breast. X-ray of the left-hand revealed a bone age 2-years ahead of her chronological age, projecting her adult height prognosis below the mid parental height. LHRH test and pelvic ultrasound were suggestive for CPP. Routine brain MRI sequences, SE T1w and TSE T2w, showed the posterior pituitary bright spot increased in size and stretched upward. The finding was considered as an anatomical variant, in an otherwise normal brain imaging. Patient was started on treatment with GnRH analogue. At a thorough revaluation, imaging overlap with adipose tissue was suspected and a new MRI scan with 3D-fat-suppression T1w-VIBE sequences demonstrated a lipoma of the tuber cinereum, bordering a perfectly normal neurohypophysis. 3D-T2w-SPACE sequences, acquired at first MRI scan, would have provided a more correct interpretation if rightly considered.
ConclusionThis is the first evidence, to our knowledge, of a cerebral lipoma mimicking pituitary gland abnormalities. Our experience highlights the importance of considering suprasellar lipomas in the MRI investigation of children with CPP, despite their rarity, should the T1w sequences show an unexpected pituitary shape. 3D-T2w SPACE sequences could be integrated into standard ones, especially when performing MRI routinely, to avoid potential misinterpretations.

引言
磁共振成像（Magnetic Resonance Imaging, MRI）是探究中枢性性早熟（central precocious puberty, CPP）患儿下丘脑-垂体区域的最优手段。针对6~8岁女童的常规扫描存在争议，因此类病例中特发性中枢性性早熟占比极高，且常合并与病情无关的偶发瘤。颅内脂肪瘤属于罕见的偶然发现，在中枢性性早熟患儿中并不常见。本文报道1例中枢性性早熟女童，其自旋回波T1加权（SE-T1w）序列上可见垂体后叶形态异常。

病例报告
患儿为7.3岁女性，因7岁时出现乳房发育就诊。既往病史与体格检查无异常，仅乳房坦纳分期为2期。左手X线片显示骨龄较实际年龄超前2年，提示其成年身高预测值低于父母身高中值。促黄体生成素释放激素（LHRH）试验与盆腔超声结果均支持中枢性性早熟的诊断。常规颅脑磁共振成像序列（自旋回波T1加权SE-T1w与快速自旋回波T2加权TSE T2w）显示垂体后叶高信号区体积增大并向上牵拉。该征象最初被认为是解剖变异，其余颅脑影像学表现均正常。随后予促性腺激素释放激素类似物治疗。经全面复查时，怀疑该征象与脂肪组织存在影像重叠，遂行三维脂肪抑制T1加权VIBE（3D-fat-suppression T1w-VIBE）序列磁共振成像，结果证实为灰结节脂肪瘤，毗邻形态完全正常的神经垂体。若初次磁共振成像时正确解读三维T2加权SPACE（3D-T2w-SPACE）序列，本可得出更准确的诊断。

结论
据我们所知，本研究为首例表现为垂体异常征象的鞍上脂肪瘤病例。本案例提示，在中枢性性早熟患儿的磁共振成像评估中，若T1加权序列出现意料之外的垂体形态改变，即使颅内脂肪瘤较为罕见，也应将鞍上脂肪瘤纳入鉴别诊断。可将三维T2加权SPACE序列纳入常规磁共振成像序列中，尤其在开展常规检查时，以避免潜在的误诊。