Double Head: Giant Solitary Occipital Scalp Plexiform Neurofibroma Without Neurofibromatosis.

A 16-year-old male presented with solitary occipital plexiform neurofibroma, which had grown slowly over several years to reach giant size, thereby mimicking a "double head." There were no features of neurofibromatosis type 1. Total excision of the neurofibroma was done by infiltrating adrenaline circumferentially around the tumor before scalp incision. The feeding arteries were identified in the dense connective tissue above the aponeurosis and ligated or cauterized. Dissection was then carried out in the loose areolar tissue preserving the periosteal layer. There was no evidence of malignant transformation on histopathology, and 5-year follow-up showed no tumor recurrence.

Giant posterior fossa arachnoid cyst causing tonsillar herniation and cervical syringomyelia.

Acquired cerebellar tonsillar herniation and syringomyelia associated with posterior fossa mass lesions is an exception rather than the rule. In the present article, we describe the neuroimaging findings in a case of 28-year-old female patient presented with a history of paraesthesia involving right upper limb of 8-month duration. Magnetic resonance imaging showed a giant retrocerebellar arachnoid causing tonsillar herniation with cervical syringomyelia. The findings in the present case supports that the one of the primary mechanism for the development of syringomyelia may be the obstruction to the flow of cerebrospinal fluid causing alterations in the passage of extracellular fluid in the spinal cord and leading to syringomyelia.