儿童毛母质瘤的影像及病理特征分析

Image and Pathology Features Analysis of Childhood Pilomatricomas

目的总结毛母质瘤的CT和MRI表现,并揭示其影像表现的病理基础。方法回顾性分析经病理证实的13例17个毛母质瘤病灶的临床及影像资料,14个病灶行影像检查,其中6个病灶行CT平扫,1个行CT增强扫描,7个行MR平扫。结果肿瘤发生于头颈部13个(耳周5个,头皮5个,耳垂1个,颌面部1个,颈部1个),躯干3个,下肢1个。行影像检查的14个病灶均位于皮下脂肪层,其中13个边界清楚,多与皮肤关系密切,肿瘤的最长径6~51 mm。CT表现:6个病灶为软组织肿块,密度与肌肉相近,其中5个病灶内可见钙化,另1个病灶表现为完全钙化;行增强扫描的1个病灶呈中度强化。MR表现:头颈部毛母质瘤中,4个T_(1)WI呈均匀等肌肉信号,4个T_(2)WI信号不均匀,5个T_(2)WI抑脂序列见环状高信号,其中3个病灶内可见网状高信号。结论毛母质瘤在CT上表现为软组织密度,内可见不同类型的钙化;MRI上T_(2)WI和T_(2)WI+FS呈特征性的网状和环状高信号表现;影像学表现与病理表现密切相关。

Objective To describe the radiological characteristics on CT and MRI of childhood pilomatricomas,and to correlate the radiological findings and pathological features.Methods The radiological findings of the 14 pilomatricomas in 13 patients were retrospectively reviewed.Among the 13 patients,six received plain CT,one received plain CT with contrast-enhancement,seven received plain MRI.Results We included 13 consecutive patients with 17 histologically proven pilomatricomas.The tumor occurred in the head and neck(n=13),in the trunk(n=3)and in the lower extremities(n=1).Moreover,of lesions in the head and neck,the tumor were in periauricular region(n=5),scalp(n=5),earlobe(n=1),midface region(n=1)and neck(n=1).The maximum tumor diameter was in the range of 6-51 mm.Most lesions were well-circumscribed,subcutaneous nodules with partial attachment to the overlying skin.CT findings:6 lesions showed soft tissue mass with similar density to muscle,of which 5 lesions showed calcification and the other one showed complete calcification.On contrast-enhanced scan,1 case showed moderate enhancement.MR were performed in 7 patients.Homogeneous isointensity on T_(1)-weighted images(T_(1)WI)were showed in 4 lesions.On fat-suppressed(FS)T_(2)-weighetd images(T_(2)WI),a ring-like hyperintensity was observed in 5 lesions,reticular hyperintensity in 3 lesions.The ring-like and reticular appearances on MR images respectively corresponded to the tissue capsule edematous stroma on pathology.Conclusion Pilomatricomas perform tissue-soft density with different patterns of calcifications on CT images.MRI typical features of pilomatricomas include reticular and ring-like hyperintensities on fat-suppressed T_(2)WI.Radiological findings are well correlated with pathological findings.