Figure 1.

(a) The whole mount composite of the dermal cyst with the squamous carcinoma arising from the cyst wall occupying the lumen of the cyst. The epidermis is uninvolved. Hematoxylin and eosin (H&E). (b) Squamous-lined cyst with preserved granular layer (bottom left) and the invasive squamous carcinoma (right) contiguous with the cyst wall. H&E 40×. (c) Poorly differentiated squamous cell carcinoma in the upper portion and moderately differentiated squamous carcinoma with cytoplasmic keratin in the bottom. H&E 100×. (d) Invasive squamous cell carcinoma with desmoplastic reaction in the surrounding soft tissues. H&E 100×.