Abstract: We present an infant girl who was born with pyloric stenosis and epidermolysis bullosa (EB). Electron microscopy of a skin biopsy specimen showed findings suggestive of EB simplex, but immunofluorescence (IF) mapping of the same specimen established the diagnosis of junctional EB. Because electron microscopy findings may sometimes be misleading, an EB patient with pyloric stenosis and electron microscopy findings suggestive of EB simplex should have a biopsy specimen examined by immunofluorescence mapping, which may confirm that the patient in fact has junctional EB.