Lichenoid, erosive and ulcerated dermatofibromas. Three additional clinico-pathologic variants

On the occasion of a case of dermatofibroma with histological lichenoid fea tures, we reviewed from our files all the cases in which the epidermis, usu ally hyperplastic in dermatofibroma, was, in some was, partially or complet ely destroyed. Among a total of 484 dermatofibromas, we found three licheno id, six erosive and two ulcerated cases. In the three lichenoid cases, the columnar epidermal basal cells were lacking (squamotization of the basal la yer) and in two of them there was a cleft between the epidermis and the der matofibroma. Three of the six eroded cases were large pedunculated dermatof ibromas with inflammatory phenomena of variable intensity. One case was in the center of a plaque of lichen simplex chronicus with some eroded area. I n the other two cases, as well as in the two ulcerated lesions, neither inf lammation nor epidermal changes usually attributed to rubbing or scratching were seen. Only in three of the eleven cases dermatofibroma was proposed ( with question mark) as a clinical diagnosis. Both followup and histopatholo gy supported the benign nature of these cases. We may conclude that: i) Lic henoid, erosive and ulcerated changes in dermato fibroma are infrequent phe nomena which may make a clinical diagnosis difficult; and ii) in the presen ce of an otherwise histopathologically typical dermatofibroma, erosion and ulceration should not be considered as suspicious of malignancy.