Dermoscopy of trichoblastic carcinoma

Abstract

Trichoblastic carcinoma is a rare malignant adnexal tumor deriving from the hair follicle. It is clinically highly similar to basal cell carcinoma (BCC), with a greater malignant potential and a higher metastatic risk [1,2]. Histopathology reveals lobules of small, basaloid cells, cytonuclear pleiomorphism, and numerous mitoses with follicular differentiation [1]. It is important to differentiate these two entities as they follow different clinical courses and, therefore, require different treatments [2]. To our knowledge, dermoscopy of this tumor has only been described once, showing scattered specks of brown pigment in a trichoblastic carcinoma of the scalp [3]. Herein, we present a dermoscopic description of a recurrent trichoblastic carcinoma. A 93-year-old patient, who underwent an excision of a lesion of the left nasolabial fold two years previously with no record of histopathology, presented to our dermatology department with a lesion on the same site of excision evolving for the lasts six months. A clinical examination revealed a well-limited ulceration surrounded by a bluish, peripheric halo with an infiltrated base. Pigmented papules and telangiectasias were also observed along the scar of the nasolabial fold (Fig. 1). Dermoscopy showed blue, ovoid nests, brown and blue globules, telangiectasias, and a central ulceration (Fig. 2). A biopsy revealed a dermal tumor proliferation made from lobules and trabeculae of basaloid cells with nuclear atypia and numerous mitoses, which was more in favor of a trichoblastic carcinoma than a BCC. A radiological assessment revealed no regional or distant metastasis. The patient was referred to the plastic surgery department for further management.