Progressive Brainstem Compression in an Infant with Neurocutaneous Melanosis and Dandy-Walker Complex following Ventriculoperitoneal Shunting for Hydrocephalus

 

Shearwood McClelland III M.D.¹, Lawrence R. Charnas M.D., Ph.D.², Karen S. SantaCruz M.D.³, Hart P. Garner M.D.¹,  Cornelius H. Lam M.D.¹

 

Departments of ¹Neurosurgery, ²Pediatrics, and ³Laboratory Medicine and Pathology, University of Minnesota Medical School, Minneapolis, MN

 

 

Introduction:

Neurocutaneous melanosis (NM) coexisting with the Dandy-Walker complex (DWC) is a rare condition, with fewer than 15 cases reported in the literature. We present a case of an infant with NM and DWC suffering from progressive brainstem compression following ventriculoperitoneal shunting (VPS) for hydrocephalus.

 

Methods:

The patient was a one-year-old boy with an uncomplicated birth history and normal developmental milestones until the age of 11 months, when he began regressing in ambulation and language function, followed by intractable vomiting one week later. Brain MRI revealed DWC with hydrocephalus, and spinal MRI established the diagnosis of NM. The patient underwent right frontal VPS placement resulting in immediate symptom relief. However, during the third postoperative week he became irritable, increasingly lethargic, unable to pull to stand, and unable to tolerate solid food without choking. Due to these symptoms and intractable vomiting, the patient presented to our institution.

 

Results:

Brain MRI revealed a new-onset diffuse cystic process with anterior and posterior brainstem compression, marked kinking of the cervicomedullary junction, melanocyte pigmentation of the left temporal lobe, diffuse leptomeningeal enhancement, and no evidence of hydrocephalus. Although posterior fossa craniectomy was performed, the degree of brainstem involvement deterred resection attempts beyond those necessary for biopsy. Pathology revealed diffuse melanocytosis, and the family decided not to pursue aggressive measures postoperatively.

 

Conclusion:

This report indicates the potential for rapid intracranial manifestation of diffuse melanocytosis in NM patients. Early neurosurgical involvement in these patients may provide tissue diagnosis with potential for decompression if the process is caught early in its course.