BACKGROUND Traumatic leptomeningeal cyst as a complication of skull fr
actures was initially thought to occur primarily in the pediatric popu
lation. The occurrence of a traumatic leptomeningeal cyst in the adult
population is rare. CASE DESCRIPTION A lump in the right parietal reg
ion of this 53-year-old man prompted a computed tomography (CT) scan.
The patient denied any symptoms and was in good health. Examination co
nfirmed a firm, nontender, nonpulsatile mass in the right parietal reg
ion of the skull. The CT scan demonstrated a 4 x 3 cm area of irregula
r bone destruction involving both the inner and outer table of the sku
ll. At operation a distinctly raised paper-thin outer table was noted,
and underneath was a soft, tan-colored mass, which measured approxima
tely 2 x 2 cm and was connected to the underlying brain through a 1 cm
dural defect. The extradural portion of the mass was amputated, the d
ura repaired with a pericranium patch, the skull defect was repaired w
ith a split thickness bone graft, and the final pathology was congruen
t with gliotic brain. CONCLUSION Although rare, this case demonstrates
a traumatic leptomeningeal cyst in an adult. (C) 1998 by Elsevier Sci
ence Inc.