Caterpillar bodies: distinctive, basement membrane-containing structures in blisters of porphyria.

In a previous study, we reported on the observation of a relatively specific, linear body in the roofs of bullae from cases of porphyria cutanea tarda. In the present study, we expand on these observations to show the presence of these bodies in lesions of pseudoporphyria cutanea tarda and erythropoietic protoporphyria. Furthermore, we have applied immunoperoxidase techniques using antibodies to type IV collagen and laminin to show that they are composed of basement membrane material. Because the segmented, elongated shapes of these bodies reminded us of the larvae of butterflies, we coined the term "caterpillar bodies" to describe them. These bodies are similar in their composition to the Kamino bodies of Spitz's nevi, cylindrical bodies in adenoid cystic carcinoma, Civatte bodies of lichen planus, and the collagenous spherules seen in a number of conditions, and may provide a unique clue to the diagnosis of the porphyric bullous eruptions.