OD and Maffucci syndrome differ with respect to the distribution of intracranial malignancies by histology, and geographical and age distribution of cases, with OD patients younger by approximately a decade, and Maffucci syndrome patients more likely to live in Asia or South America.

In this report the authors discuss a patient who experienced symptoms of an acute right frontal, intraparenchymal pneumatocele while on an airplane descending to an international airport. This rare complication of an ethmoid sinus osteoma that eroded upward through the dura mater is described along with a literature review. A persistent headache and inappropriate behavior consistent with a frontal lobe syndrome brought the patient to clinical and imaging evaluation, which revealed a large right frontal lobe pneumatocele and an associated ethmoid sinus osteoma extending upward into the frontal lobe. Through a right frontal craniotomy, the air cavity was evacuated, the osteoma partially excised, and the dural defect closed using a vascularized pericranial flap. Postoperatively, the patient made an unremarkable recovery. For patients with air sinus osteomas extending into the cranial cavity, air travel or other barotrauma may result in a life-threatening tension pneumatocele.

Ollier disease and Maffucci syndrome are rare syndromes in which there is deforming dysplasia of cartilage, primarily but not exclusively involving the metaphyses and diaphyses of long bones. In a minority of patients, dysplasia can lead to sarcomatous degeneration, producing chondrosarcomas. There also appears to be an association with other neoplasms. Little has been written about the association between Ollier disease and intracranial tumors, and these papers have largely consisted of case reports in adults. The authors present the case of a 6-year-old girl with left arm osseous changes consistent with Ollier disease and a biopsy-proven thalamic glioblastoma multiforme. They then examine the co-occurrence of brain tumors in conjunction with a dyschondroplasia syndrome in children and adolescents to assess the presentation, treatment offered, and disease course of similar cases. Eight other such cases were identified, 6 in patients with Ollier disease (ranging in age from 7 to 18 years), and 2 with Maffucci syndrome (both in late adolescence). Including our own patient, 7 of the 9 cases of comorbid dyschondroplasia and intracranial malignancy occurred in girls. Some patients presented soon after the acute onset of symptoms, and others had a more subtle, protracted course over as many as 2 years. Some tumors were deemed resectable and others not. In only 1 instance was follow-up beyond 1 year reported.

Central pontine myelinolysis (CPM) and extrapontine myelinolysis (EPM) are dire neurological disorders, characterized by severe damage to the myelin sheath of neurons, which typically result from rapid correction or overcorrection of systemic hyponatremia. For many years, both conditions have been considered universally fatal, though survivors have been reported more recently. Pediatric cases are rare. We present a 13-year-old boy with panhypopituitarism secondary to repair of a nasofrontal encephalocele in infancy, managed on long-term corticosteroid, deamino arginine vasopressin and thyroid hormone. He presented with severe hyponatremia (116 mEq/l), which during correction rapidly and unexpectedly increased to 176 mEq/l, resulting in profoundly impaired consciousness. Brain imaging revealed multiple bilateral changes in the basal ganglia, thalamus, pons and cerebral white matter, consistent with both CPM and EPM. Malignant cerebellar edema necessitated emergent suboccipital craniectomy, with subsequent improvement in level of consciousness and imaging postoperatively. However, he succumbed to acute cardiorespiratory arrest 8 weeks later. Nine similar cases from the literature are reviewed.