MR Imaging Findings of Giant Trichilemmal Carcinoma on the Scalp

Abstract

We describe the magnetic resonance imaging findings of a huge trichilemmal carcinoma (TLC) on the parietal and occipital region of the scalp in one patient. Our aim is to discuss the clinical, radiologic, and pathologic features of scalp TLC and to review relevant literature regarding this tumor. One patient with recent rapid tumor growth in the parietal and occipital region of the scalp underwent MR studies and subtotal resection. The tumor was seen as a poorly marginated and lobulated soft-tissue mass with isointense signal on T1-weighted images and hyperintense signal on T2-weighted images. Necrosis and ulceration were also found on the tumor surface. The TLC has been massively invading the nearby skull, meninges, brain tissue, and superior sagittal sinus. After exhibiting contrast, the tumor showed significant enhancement, with small portions remaining unenhanced. Subtotal excision of the mass and reconstruction of the scalp were performed. Microscopically, the mass was composed of trabecular growth of tumor cells with clear cytoplasm, prominent nucleoli, frequent mitoses, and foci of trichilemmal keratinization. Tumor on the scalp with heterogeneous, mixed signals on T2-weighted images, significant enhancement of solid portion, and local infiltration accompanied by surface deep ulceration may indicate a TLC. Wide surgical excision with tumor-free margins remains the best choice for treatment.