Department of Radiology, Gifu University, Gifu, Japan.
Department of Pathology, Gifu University, Gifu, Japan.
Neuroradiol J. 2021 Dec;34(6):615-621. doi: 10.1177/19714009211017789. Epub 2021 Jun 1.
The purpose of this study was to evaluate computed tomography and magnetic resonance imaging of benign trichilemmal cysts and proliferating trichilemmal tumours.
Nineteen histologically confirmed cutaneous lesions with trichilemmal keratinisation (12 trichilemmal cysts and seven proliferating trichilemmal tumours) were enrolled. Among them, 10 lesions (six trichilemmal cysts and four proliferating trichilemmal tumours) were examined by computed tomography, while 13 lesions (eight trichilemmal cysts and five proliferating trichilemmal tumours) were examined by magnetic resonance imaging. Computed tomography and magnetic resonance imaging characteristics were retrospectively reviewed.
Sixteen lesions (84%, 10 trichilemmal cysts and six proliferating trichilemmal tumours) occurred on the scalp. Lobulated margins were observed in five lesions (26%, three trichilemmal cysts and two proliferating trichilemmal tumours). With respect to computed tomography attenuation, calcification (>200 Hounsfield units) was observed in seven lesions (70%, five trichilemmal cysts and two proliferating trichilemmal tumours), hyperdense areas (≥80 and ≤200 Hounsfield units) in six (60%, three trichilemmal cysts and three proliferating trichilemmal tumours), and soft tissue density areas (<80 Hounsfield units) in nine (90%, five trichilemmal cysts and four proliferating trichilemmal tumours). On T1-weighted images, intratumoral hyperintensity was only observed in eight trichilemmal cysts but no proliferating trichilemmal tumours (100% vs. 0%, <0.01). On T2-weighted images, hypointense rim and intratumoral hypointensity was observed in all 13 lesions (100%, eight trichilemmal cysts and five proliferating trichilemmal tumours), and linear or reticular hypointensity was observed in 10 (77%, six trichilemmal cysts and four proliferating trichilemmal tumours).
Trichilemmal cysts and proliferating trichilemmal tumours predominantly occurred on the scalp with calcification, and usually exhibited linear or reticular T2 hypointensity. Intratumoral T1 hyperintensity may be a useful imaging feature for differentiating trichilemmal cysts from proliferating trichilemmal tumours.
本研究旨在评估良性外毛根鞘囊肿和增生性外毛根鞘肿瘤的 CT 和 MRI 表现。
纳入 19 例经组织学证实具有外毛根鞘角化的皮肤病变（12 例外毛根鞘囊肿和 7 例增生性外毛根鞘肿瘤）。其中，10 例病变（6 例外毛根鞘囊肿和 4 例增生性外毛根鞘肿瘤）行 CT 检查，13 例病变（8 例外毛根鞘囊肿和 5 例增生性外毛根鞘肿瘤）行 MRI 检查。回顾性分析 CT 和 MRI 特征。
16 例（84%，10 例外毛根鞘囊肿和 6 例增生性外毛根鞘肿瘤）病变发生于头皮。5 例（26%，3 例外毛根鞘囊肿和 2 例增生性外毛根鞘肿瘤）表现为分叶状边缘。CT 衰减值方面，7 例（70%，5 例外毛根鞘囊肿和 2 例增生性外毛根鞘肿瘤）可见钙化（>200 亨氏单位），6 例（60%，3 例外毛根鞘囊肿和 3 例增生性外毛根鞘肿瘤）可见高密度区（≥80 且≤200 亨氏单位），9 例（90%，5 例外毛根鞘囊肿和 4 例增生性外毛根鞘肿瘤）可见软组织密度区（<80 亨氏单位）。T1 加权像上，仅 8 例外毛根鞘囊肿（100%）表现为瘤内高信号，而无增生性外毛根鞘肿瘤（0%）（<0.01）。T2 加权像上，所有 13 例病变（100%，8 例外毛根鞘囊肿和 5 例增生性外毛根鞘肿瘤）均表现为低信号环和瘤内低信号，10 例（77%，6 例外毛根鞘囊肿和 4 例增生性外毛根鞘肿瘤）表现为线性或网状低信号。
外毛根鞘囊肿和增生性外毛根鞘肿瘤主要发生于头皮，伴钙化，通常表现为 T2 低信号的线性或网状改变。瘤内 T1 高信号可能是鉴别外毛根鞘囊肿和增生性外毛根鞘肿瘤的有用影像学特征。
