Peritoneal Washings and Ovary
epithelium shares its embryologic lineage. The single or focally
stratified layer of columnar to cuboidal surface epithelium that
covers the ovaries may invaginate focally into ovarian stroma,
resulting in the formation of epithelial inclusion cysts. Being of
mullerian derivation, the surface epithelium is capable of pheno-
typic alteration to resemble serous (tubal), mucinous (endocervi-
cal or goblet cell), endometrial, or transitional (urothelial) cells.
Each cell type may be recapitulated in epithelial ovarian tumors.
The millions of ova present in the neonatal ovary dwindle in
number throughout reproductive life, ultimately to be depleted
by menopause. The developing ova are surrounded by a shell of
granulosa cells that secrete estradiol (E2) during folliculogenesis.
The outer layers of the shell are composed of theca interna cells
that produce a variety of hormones, including E2 and andros-
tenedione. After ovulation, the follicle-lining cells become lutei-
nized, acquire abundant eosinophilic cytoplasm, and produce
copious amounts of progesterone.
The ovarian stroma is largely composed of spindled cells that
resemble fibroblasts, collagen, and various stromal cells with an
enormous capacity for hormone and enzyme production.
Non-neoplastic Cysts
Fig. 12.6 Follicle cyst. Small, round, hyperchromatic nuclei are surrounded
by a moderate amount of granular cytoplasm. Aspiration (Papanicolaou x HP).
hyperchromasia in some granulosa cells, the high nucleocyto-
plasmic ratio, high mitotic rate, and prominent nucleoli become
quite worrisome. A careful search for typical granulosa cells
should be undertaken to help classify the cyst.55
Follicle Cyst
Follicle cysts
arise from cystic enlargement of an ovarian folli-
cle. They are usually unilateral, occur most frequently during
the reproductive years, and may cause pelvic pain. Most regress
spontaneously within a few months, but persistent cysts must be
evaluated to exclude neoplasia. Their occasional detection in the
fetus or newborn is attributed to maternal hormone stimula-
tion. Pre- and perinatal ovarian cyst aspiration has been accom-
plished successfully.36,37,50
Aspirations from follicle cysts vary from sparsely cellular
to exceedingly hypercellular. The background may be clean or
hemorrhagic.51 Granulosa cells, approximately the size of histio-
cytes, appear singly or in fragments as sheets or three-dimen-
sional clusters (Fig. 12.6). Rarely, cells may appear to surround
a small central luminal space, similar to a Call-Exner body.52,53
Granulosa cell nuclei are round to oval with distinctly granular
chromatin that may appear hyperchromatic. Focal chromatin
clearing and one or two small nucleoli may be identified. Mitotic
figures are commonly encountered and may be numerous (up to
38 mitoses per 10 high-power fields).51 Nuclear grooves may be
identified in some granulosa cells54 or may be entirely absent.51
The cells are round or polygonal, tend to have indistinct cell
borders, and have a minimal to moderate amount of foamy or
granular cytoplasm. Some follicle cysts contain scattered lutein-
ized cells with abundant foamy cytoplasm; these cells may be
difficult to distinguish from histiocytes.35 No ciliated cells or
ciliated fragments should be identified.
Key features of follicle cyst
• Sparse to abundant cellularity;
• Granulosa cells with round to oval nuclei;
• Grooved or nucleolated nuclei;
• Granular to foamy cytoplasm, usually scant;
• May be very mitotically active; and
• Clean or hemorrhagic background.
The high cellularity, cytologic atypia, and mitotic activity
seen in some follicle cysts may be so disturbing as to simulate
malignancy.52,53 In these cases, cellular discohesion, nuclear
Luteinized Cyst
Luteinized cysts
represent the delayed resolution and cystic dila-
tion of a corpus luteum. Their walls are composed of multiple
layers of luteinized granulosa cells. They contain serosanguine-
ous fluid or clotted blood with a variable amount of organiz-
ing granulation tissue. Cytologically, the fluid shows luteinized
granulosa cells with abundant foamy cytoplasm (Fig. 12.7).
These cells may be poorly preserved and resemble histiocytes.56
Scattered typical granulosa cells may be encountered.54 The
background contains blood and/or fibrin. Occasionally, spin-
dled fibroblasts may be encountered.
Key features of luteinized cyst
• Moderate cellularity;
• Luteinized granulosa cells with abundant cytoplasm;
• Degenerative changes including nuclear hyperchroma-
sia; and
• Bloody or fibrinous background.
Endometriotic Cyst
Endometriotic cysts
of the ovary arise as a consequence of cyclic
bleeding into ovarian tissue. The intracystic fluid is hemorrhagic
and appears brown-black, resulting in the so-called chocolate
cyst. Cytologic examination of this fluid reveals numerous
hemosiderin-laden macrophages and blood. Scattered endome-
trial cells can be identified in some but not all cysts.40 These
cells tend to be small, hyperchromatic, and degenerated.57 They
appear in loose fragments and sometimes show nuclear mold-
ing.58 "Collagenous bodies," ovoid fragments of type IV colla-
gen derived from the basement membrane of the endometrial
glands, may also be present.59
Key features of endometriotic cyst
• Scant to moderate cellularity, primarily hemosiderin-
laden macrophages, is present;
• Endometrial cells may or may not be identified, are
often degenerated, and may be seen in close packed
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