Imaging findings of trichilemmal cyst and proliferating trichilemmal tumour

Abstract

Purpose The purpose of this study was to evaluate computed tomography and magnetic resonance imaging of benign trichilemmal cysts and proliferating trichilemmal tumours. Methods 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. RESULTS 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%, P<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). Conclusion 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.

The Value of Ultrasound for Differentiating Trichilemmal Cysts From Epidermoid Cysts

“…Several studies have evaluated the diagnostic performance of TCs using computed tomography, US, and magnetic resonance imaging 15,23 . However, a prediction model has not yet been established.…”

“…Several studies have evaluated the diagnostic performance of TCs using computed tomography, US, and magnetic resonance imaging. 15,23 However, a prediction model has not yet been established. In this study, we not only analyzed the clinical and US features of TCs but also established a prediction model to predict TCs from ECs.…”

Malignant proliferative ependymoma of the neck with lymph node metastasis: A case report

“…Predominantly, 90% of these tumors manifest on the scalp, followed by occurrences on the forehead and neck skin[ 9 ]. Moreover, most instances of MPTT are conceived as localized malignancies evolving from pre-existing PTT lesions[ 10 ]. It is noteworthy that there exist limited reports of PTT undergoing malignant transformation on the scalp.…”

“…The radiographic representation of PTT/MPTT harmonizes with its clinical manifestation. Lesions on the head and neck typically exhibit characteristics of cystic-solid or cystic masses[ 10 ]. Appearing as low signal on T1WI images or high signal on T2WI with enhancement of the solid component.…”

“…Proliferative ectodermal root sheath tumors are categorized into three groups: Group I (benign), marked by restricted lesions, mild nuclear heterogeneity, lack of mitotic activity, and absence of necrosis or lymphovascular infiltration; group II (low malignancy), characterized by histological irregularity, localized infiltration, and potential spread to dermal and subcutaneous tissues; and group III (highly malignant), characterized by infiltrative growth, pronounced nuclear heterogeneity, elevated mitotic and necrotic activity, and lymphatic and vascular infiltration[ 10 , 12 ]. Histologically, PTT masses typically display lobulated, well-defined contours without encapsulation.…”