Leptomeningeal cyst due to vacuum extraction delivery in a twin infant

A rare case of a leptomeningeal cyst is reported in a twin male neonate delivered using a vacuum extractor, who presented a huge, non-pulsating, oedematous mass overlying the frontal fontanelle after birth. The mass was initially diagnosed as a cephalo haematoma. Ultrasonography indicated intracranial bleeding and a subsequent CT scan revealed an intraparenchymal bleeding above the left frontal horn, combined with a thin, left-sided, subdural haematoma and subarachnoid haemorrhage in the left Sylvian fissure. Apart from a bulging soft and round formation (2 x 2 x 3 cm) next to the anterior fontanel growing since birth, the neurological development of the infant was normal. MRI examination at the age of 7 months revealed that it consisted of a cystic mass (leptomeningeal cyst) connected to the left frontal horn, stretching right through the brain and also penetrating the dura mater. No signs of the perinatal haematomas were observed at this time. Surgical treatment, with fenestration of the cyst into the frontal horn and a watertight duraplasty with a periosteal flap and thrombin glue covered by small bone chips, was performed at 9 months of age. Due to a residual skull bone defect a second cranioplasty with autologous skull bone was performed three and half years later. During a follow-up period of 12 years the neurological and psychological development of the boy has been indistinguishable to that of his twin brother, indicating the satisfactory outcome of the treatment.