Primary Nonneoplastic Cysts Overview

(Left) Gross pathology shows

an autopsied case of a colloid

cyst, sectioned in the coronal

plane through the foramen of

Monro. Note the gelatinousappearing lobulated cyst ﬈

with the fornices st straddling

the cyst. This patient died of

sudden obstructive

hydrocephalus. (Courtesy J.

Townsend, MD.) (Right) Gross

pathology of an autopsied

brain, seen from below, shows

a large arachnoid cyst of the

middle cranial fossa. The cyst

contained cerebrospinal fluid

within split layers of arachnoid

﬈. (Courtesy J. Townsend,

MD.)

(Left) Gross surgical specimen

of a sectioned dermoid cyst

shows the characteristic lining

of stratified squamous

epithelium plus intracystic

keratin debris ſt. Matted,

tangled hairs ﬊ are present

within the cyst, which

contained thick, greasy

sebaceous material when

sectioned. (Courtesy R.

Hewlett, MD.) (Right)

Microscopy of a typical

dermoid cyst shows squamous

epithelium ﬈ and sebaceous

glands ﬊ lining a cavity that

contains desquamated

keratinaceous debris.

(Left) Close-up view of an

epidermoid cyst shows the

cauliflower-like cyst surface

that is composed of nodular

masses of squamous

epithelium and pearly white

keratin. (Right) Autopsy

specimen shows a small,

gelatinous-appearing nodule

﬈ just anterior to the pons.

Ecchordosis physaliphora, a

notochordal remnant, grossly

appears similar to neurenteric

cyst. (Courtesy R. Hewlett,

MD.)

Brain: Pathology-Based Diagnoses: Neoplasms,

Cysts, and Disorders

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