A Case of Dissecting Cellulitis which Was Initially Suspected to Be a Trichilemmal Cyst

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.

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A Rare Case: Primary Venous Malformation in Parietal Bone

Skin Appendage Disorders ◽

10.1159/000514697 ◽

2021 ◽

pp. 1-4

Author(s):

Serhat Yarar ◽

Ilker Uyar ◽

Mehmet Emin Cem Yildirim ◽

Mehmet Dadacı ◽

Bilsev Ince

Keyword(s):

Vascular Malformation ◽

Rare Case ◽

Histopathological Examination ◽

Vascular Malformations ◽

Venous Malformation ◽

Parietal Bone ◽

Hair Density ◽

Trichilemmal Cyst ◽

Advancement Flaps ◽

Rotation Advancement

Primary intraosseous vascular malformations (PIVMs) are rare intraosseous lesions, accounting for approximately 0.5–1% of all intraosseous tumours. In this case report, we aimed to present a rare case of intraosseous vascular malformation causing a large lytic area in the parietal bone. A 25-year-old male patient was admitted to the clinic with a mass on the parietal bone. On physical examination, it was observed that the hair density on the mass was decreased, the mass had a soft consistency, and there was no pain on palpation. The patient was operated under local anaesthesia with a provisional diagnosis of a trichilemmal cyst. However, intraoperative diagnosis was a vascular malformation. There was a 3-cm full-thickness defect on the parietal bone caused by the lesion. The mass was excised completely while preserving the integrity of the dura. The resulting defect was reconstructed with bilateral rotation advancement flaps. The calvarial defect was not reconstructed due to equipment inadequacy. No complications were encountered in the postoperative period. Ninety-three PIVM cases have been reported in the skull since 1845. In very few of these cases, the mass is located in the parietal bone. The pathogenesis of PIVMs is not completely understood. The definitive diagnosis is made by histopathological examination. The therapeutic gold standard is surgery. Surgeons should keep in mind that radiological examination before the operation could prevent undesirable complications.

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