Translucent basal cell carcinoma with a single cyst of the upper eyelid

Dear Editor, An 88-year-old Japanese woman presented with a cystic nodule on her left upper eyelid. The nodule enlarged rapidly over 4 months before her first visit to our hospital. Physical examination revealed a brown-black, translucent and cystic nodule with telangiectasia, measuring 6 mm in diameter (Fig. 1a). Based on clinical findings, we initially considered the diagnosis of apocrine hidrocystoma (AH). Under local anesthesia, we excised the nodule. Histological examination revealed a large, single, cystic tumor located mainly in the dermis (Fig. 1b). The tumor comprised nests of basaloid cells with low atypicality and melanin pigmentation (Fig. 1c), peripheral palisading cell arrangement, but no squamous epithelium with granular layers and tubular structures (Fig. 1d). The findings of trichoblastoma, such as fibrous interstitium and structures like follicular germinative cells, were not apparent. The cystic tumor showed continuation with the overlying epidermis and some small nests of basaloid cells were attached to the overlying epidermis near the cystic lesion (Fig. 1e). The mucin deposition in the stroma and the nest was apparent just outside the nest (Fig. 1f). The findings of apocrine origin, such as intraluminal papillary projections or layers of cuboidal cells, were not apparent. The cystic tumor showed extensive degeneration, containing erythrocytes centrally, but no keratin (Fig. 1g). Immunohistochemistry examination showed tumor nests negative for