Trichoblastic carcinoma of the pinna. A rare case

Abstract

Adnexal tumors of the hair follicle can be regarded as lesions that show similar differentiation to one or more portions of the hair follicle. Trichoblastic carcinoma is a rare malignant adnexal tumor, which usually occurs on the scalp. There have been reported cases with regional lymph node metastasis. We report a case of a 65 years old man with a painless irregular mass of the posterior surface of the right pinna, which was slowly growing over a 5-year period. He had a history of a similar lesion on the same site, which was removed 8 years before he presented to us. We excised the lesion and the defect was covered with an advancing flap. Because of the histology result the patient was re-operated and reviewed for over 3 years and there wasn't any sign of recurrence.

Keywords: malignant pilar tumor; pilar carcinoma; trichoblastic carcinoma.

Figure 1.. Histology of the dermal tumor nodule. Cystic wall of the tumor nodule with lobular and trabecular structures of squamous epithelial cells. Central cystic and peripheral solid areas (inset). Hematoxylin-eosin stain x128, inset x21

Figure 2.. A. Pilar tumor showing lobules and strands of atypical epithelial cells without central keratinization. Hematoxylin-eosin stain x120. B. Lobules of squamous neoplastic cells with atypical features. Hematoxylin-eosin stain x120. C. Neoplastic cells demonstrating nuclear pleomorphism and increased mitotic figures (arrows). Hematoxylin-eosin stain x160. D. Disposition of neoplastic cells around a hyalin stroma. Increased mitotic figures are noticed (arrows). Hematoxylin-eosin stain x160