Fig. 19.115 Smear of peritoneal effusion containing cells of mucinous
ovarian adenocarcinoma (Papanicolaou x MP).
Fig. 19.116 Smear of peritoneal effusion depicting a fragment of ovarian
papillary serous adenocarcinoma containing psammoma bodies
(Papanicolaou x HP).
of them highly vacuolated (Fig. 19.115). Papillary clusters of
adenocarcinoma may contain psammoma bodies (Fig. 19.116);
however, when small in number, psammoma bodies can be
easily overlooked in Papanicolaou-stained smears, being much
more easily detectable in cell-block preparations and even in
stained wet films (see Fig. 19.12). Figure 19.116 illustrates papil-
lary ovarian carcinomas bearing several psammoma bodies.
Individual adenocarcinoma may be quite large, even gigan-
tic, due to their large cytoplasmic vacuoles. Such vacuolation
does not necessarily signify that the cytoplasm contains mucin;
it may be due to glycogen or a degenerative change. A peritoneal
effusion aspirated from a woman and which contains numerous
large, hypervacuolated adenocarcinoma cells, isolated and in
papillary groups, is most likely to be a manifestation of ovarian
The prognosis of atypically proliferating ovarian epithelial
neoplasms (tumors of low malignant potential, borderline
tumors) with some of the histologic features of carcinoma is
significantly better than that of invasive ovarian carcinoma
and generally requires a less aggressive therapeutic approach.
Distinguishing between the two types of carcinoma in a peri-
toneal fluid may therefore have some practical application.
Fig. 19.117 Smear of peritoneal effusion depicting cells of metastatic
ovarian serous cystadenocarcinoma. The cells are fairly small and
uniform in shape and size and occur isolated or in small groups. Vacuolation
is not prominent. Such cells could be mistaken for mesothelial cells
(Papanicolaou x HP).
Johnson and co-workers compared the cytologic presentation in
peritoneal fluids of atypically proliferating ovarian tumors with
that of frankly invasive ovarian carcinoma.229 Cytologic prepa-
rations of the former contained large, cohesive papillary frag-
ments with smooth borders. The neoplastic cells were relatively
small and uniform, with a high nucleocytoplasmic ratio, few
intracytoplasmic vacuoles, and inconspicuous nucleoli. Mitotic
figures were rare. In contrast, peritoneal fluids from patients
with invasive ovarian carcinoma contained smaller papillary
fragments that were not cohesive and had irregular borders. The
neoplastic cells were relatively large and pleomorphic, with low
nucleocytoplasmic ratios, abundant intracytoplasmic vacuoles,
and prominent nucleoli. Most preparations contained many
isolated cells and mitotic figures.
Some serous adenocarcinomas present with relatively small
cells isolated or arranged in small groups. Their cytoplasm may
show little vacuolation, and the nuclei do not exhibit pronounced
deviation from those of mesothelial cells (Fig. 19.117). Such cells
are likely to be derived from a fairly well-differentiated serous
adenocarcinoma, and their morphologic similarity to mesothe-
lial cells is a reflection of their origin from germinal epithelium of
the ovary, which shares an embryonic origin with mesothelium.
Ovarian teratomas are usually benign but malignant variants
occur which may exfoliate cells into an accompanying peritoneal
effusion. While the teratoma may exhibit cellular differentiation
of several recognizable types, portions of it may consist of undif-
ferentiated cells. Figure 19.118 is an example of a malignant
ovarian teratoma which exfoliated small undifferentiated cells
into a peritoneal effusion. Similarly, ovarian dysgerminoma, an
uncommon neoplasm, may exfoliate cells into the peritoneal
cavity to cause effusion; Fig. 19.119 illustrates such an example.
Examples of cells of the rare small-cell carcinoma of the ovary
and Sertoli-Leydig tumor in peritoneal fluids have been described
by Selvaggi and Valente and colleagues, respectively.230,231
Key features of ovarian neoplasms
• Adenocarcinomas: mucin-producing (highly
vacuolated) or serous (psammoma bodies); and
• Occasional germ cell neoplasms: variable cytologic