Midline cutaneous lumbosacral lesions: not always a sign of occult spinal dysraphism.

OBJECTIVE: The authors report two unusual cases of extraspinal midline lumbosacral lesions that resembled the usual skin markers of occult spina bifida. PATIENTS AND METHODS: The pathological diagnosis of the masses was plexiform neurofibroma and mastocytoma, respectively. RESULTS: Some lesions, as those we are reporting, although occurring at the lumbosacral midline, do not necessarily belong to occult spinal dysraphism, as was initially suspected. Plexiform neurofibroma and skin mastocytoma are very rare indeed in this spinal location. CONCLUSION: The two cases represent an important addition to the differential diagnosis of a congenital dorsal midline mass.