Ultrastructure of the epidermal-dermal junction and cutaneous basal lamina in Bowen's disease

Ten tissue sections from 10 examples of Bowen's disease were excised from paraffin blocks, rehydrated, and incubated in 90% formic acid at 45 degrees C for 18 h. The epidermis was gently removed with the aid of a dissecting microscope, and the remaining dermis with attached basal lamina was processed for scanning electron microscopy. This surface showed a well-preserved basal lamina. The dermal papillae in the areas of Bowen's disease were elongated and had frequent secondary protrusions. The normal 0.5 mu interconnecting corrugations were often replaced by either broad, coarse corrugations or by large areas of smooth-to-undulating basal lamina. This study demonstrates marked alterations in spatial interactions between neoplastic epidermis and underlying dermis in Bowen's disease.