Benign but not harmless: cerebral lymphangioma-related cortical shift causing progressing isolated upper extremity paresis.

Lymphangiomas (LMs) are rare, benign congenital malformations that can occur in any part of the body but most frequently in the head and neck region-although rarely intracranially.We present a case of a male in his 60s with sudden onset of paresis in his right fourth and fifth fingers that progressed to a diffuse right upper extremity paresis. Extensive paraclinical examinations were performed, with brain CT and MRI showing an osteolytic lesion over the left side of the cranium corresponding with the motor strip and accompanying brain herniation. The patient underwent neurosurgery with removal of the affected bone, biopsies of the tissue and bone and coverage with a titanium mesh. The histopathological diagnosis was a benign LM. Six months postoperatively, the paresis had improved significantly.Despite being very rare, LMs of the skull can cause significant neurological deficits depending on their location. MRI and histopathological analysis are key to diagnosis.