Presentation
Head swelling noted by the mother.
Patient Data
Cerebrospinal fluid density masses are noted at the parasagittal regions adjacent to the superior sagittal sinus associated with well-defined lytic erosions of the inner vault of the skull vertex.
Case Discussion
CT findings are suggestive of arachnoid granulations.
Arachnoid granulation is the growth of the arachnoid membrane into the dural sinuses, which vary widely in site, number, size, and morphology. Occasionally, it extends partly up to the inner table of the skull, and even expands into the diploic space and eventually involves the outer table, mimicking malignant osteolytic lesions.
The most common site for arachnoid granulation is at the superior sagittal sinus.
Most cases are usually asymptomatic and discovered incidentally in imaging studies.