Characterization of retraction spaces in basal cell carcinoma using an antibody to type IV collagen

'Retraction spaces' observed in 18 of 30 basal cell carcinomas were readily classified into two distinct types using the PAP immunoperoxidase technique and an antibody to human type IV collagen, raised in rabbits. In processing artefacts, true retraction spaces were observed between the epithelial cells and the basal lamina, while in areas of stromal mucinous change, accumulation of mucinous material resulted in clear spaces separating the normal stroma from the overlying basal lamina.