a 70-year - old japanese man presented at our hospital with an asymptomatic , 20  30 mm irregularly shaped blackish , flat elevated plaque with a gray nodule in the periphery on his left lower leg ( fig . the lesion had been present for 10 years and had recently enlarged , associated with bleeding . dermoscopy revealed leaf - like areas , large blue - gray ovoid nests and multiple blue - gray globules ( fig . basal cell carcinoma and malignant melanoma were listed as suspected diagnoses , and we performed an excisional biopsy of the tumor . histopathological examination of the tumor revealed infundibular structures of the outer hair sheath in the center of the plaque , which consisted of three distinct parts ( fig . 2a ) . the first part showed circumscribed massive aggregation of basophilic basaloid cells containing abundant melanin granules with peripheral palisading and retraction spaces ( fig . this part of the tumor exhibited trichilemmal keratinization with squamous eddies , which were surrounded by a fibrous stroma ( fig . the third part showed reticular aggregation of basaloid cells with small infundibular cystic structures in the papillary dermis ( fig . the stromal part showed no fibrosis and abundant mucin deposition staining positive with alcian blue ( fig . immunohistochemical staining revealed diffuse positivity for anti - bcl-2 in the first part ( fig . 3b ) , positivity only at the periphery of tumor nests in the second part ( fig . microscopic examination of the tumor showed that it consisted of three distinct histological types : massive aggregation of basophilic cells was diagnosed as solid - type basal cell carcinoma , massive aggregation of clear cells with trichilemmal keratinization was diagnosed as proliferating trichilemmal tumor , and reticular small aggregations of basophilic basaloid cells in the papillary dermis were diagnosed as infundibulocystic basal cell carcinoma . basal cell carcinoma with follicular differentiation in 1987 by tozawa and ackerman , and later in 1990 the tumor was proposed as a variant of basal cell carcinoma showing differentiation to infundibular cyst - like structures by walsh and ackerman . clinically , the tumor presents as small papules / nodules , most commonly on the face . characteristic histopathological features of the tumor are small symmetrical , circumscribed aggregations of basaloid cells containing numerous infundibular cyst - like structures . infundibulocystic basal cell carcinoma is different from trichoepithelioma in that there are no follicular bulbs and papillae , no stromal fibrosis around the tumor , reticulated pattern of neoplastic cells , and abundant epithelial mucin . in the present case , anti - bcl-2 immunohistochemical staining was diffusely positive in portions of typical basal cell carcinoma and infundibulocystic basal cell carcinoma . , bcl-2 is present within basal keratinocytes , mesenchymal cells of follicular papilla , clear cells of eccrine glands , melanocytes and lymphocytes . anti - bcl-2 staining is useful for distinguishing between trichoepitheliomas and basal cell carcinoma , the former staining positively in the periphery of tumor nests , whereas the latter shows diffuse and widespread staining in all tumor nests . basal cell carcinoma is a neoplasm proposed to be derived from epithelial germ cells , and infundibulocystic basal cell carcinoma is derived from the infundibulum of the hair follicle , whereas proliferating trichilemmal tumor is derived from the hair follicle isthmus . there have been four reports of basal cell carcinoma arising with trichilemmoma without a pre - existing sebaceous nevus . taken together , the present findings suggest that basal cell carcinoma may be derived from hair germ cells , including the outer hair sheath and hair follicular infundibulum . the authors report no conflicts of interest . there were no funding sources for this work .