Unilateral lentiginosis--a segmental neurofibromatosis without neurofibromas

Segmental neurofibromatosis (NF) is a usually non-inherited form of NF that is characterized by unilateral neurofibromas and/or café-au-lait spots. In partial unilateral lentiginosis (PUL), apart from unilateral lentigines, café-au-lait spots of different dimensions have been described in some patients without fulfilling the diagnostic criteria for NF. We report on three patients representing the 4th to 6th cases of segmental NF without neurofibromas. The diagnosis resulted from unilateral café-au-lait spots of different sizes in all patients and axillary "freckling" and associated skeletal alterations in two patients each. As these findings are clinically and histologically comparable to reported cases of PUL and moreover fulfil the diagnostic criteria for segmental NF, our cases support the hypothesis that PUL is a segmental NF lacking neurofibromas.