Metamorphosis of dermal cylindroma: possible relation to malignant transformation. Case report of cutaneous cylindroma with direct intracranial invasion.

A case of locally invasive cutaneous cylindroma is reported. This neglected scalp tumor, 6.5 cm in greatest dimension, initially invaded the calvaria at the time of the first operation. A recurrence infiltrated the dura and presented as an intracranial space-occupying lesion. No brain invasion was present and distant metastases were not documented. The patient remains well 2 1/2 years after tumor resection. Light and electron microscopic appearance of the recurrent tumor revealed distinct morphologic features, which may be of use in predicting the biologic behavior of cutaneous cylindromas. This case documents the low biologic aggressiveness of cylindroma and stresses the necessity of complete surgical excision of neoplasms with atypical morphologic features.