Diagnostic Cytology
Table 10.2 The staging of endometrial carcinoma using the
International Federation of Obstetricians and Gynecologists
(FIGO) System (abridged)
Stage 1
Carcinoma limited to the endometrium (Stage 1 a), or
Carcinoma involving the inner half (Stage 1 b) or
Outer half of myometrium (Stage 1c)
Stage 2
Carcinoma invades the cervix but does not extend
beyond uterus
Stage 3
Carcinoma involves the uterine serosa, adnexa, vagina,
rectum, pelvic wall, and/or urinary bladder (by direct
extension or metastasis), or
Malignant cells in ascites or peritoneal washings, or
Pelvic or para-aortic lymph node metastases
Stage 4
Carcinoma invades urinary bladder or bowel mucosa, or
Distant metastasis
Fig. 10.4 FIGO Grade 1/3, endometrioid adenocarcinoma of the
endometrium. Endometrial biopsy, histologic section (H&E x MP). Note the
back-to-back glands, and retained endometrioid appearance.
may occur (Table 10.1). In both types I and II adenocarcinomas
the normal glandular architecture of the endometrium is lost,
and the glands show architectural complexity with intraglan-
dular bridging and epithelial stratification (Fig. 10.4). This pro-
liferation of abnormal glands results in a back-to-back pattern
with minimal stroma. The stroma looses its normal endometrial
appearance, and acquires a fibrotic (desmoplastic) appearance.
Areas of the adenocarcinoma often undergo necrosis. Necrotic
debris may be evident in gland lumina. The malignant epithe-
lial cells are larger than normal; their shape may be columnar,
cuboidal, polygonal, or round. The amount of cytoplasm is
variable. Often the cellular polarity within the gland lining is
lost. The large nuclei are round or oval, and have an abnormal
chromatin pattern. Mitotic activity is evident.
A number of architectural and cytologic features are used to
differentiate type I from type II adenocarcinomas. The malignant
glands of type I (endometrioid) adenocarcinomas retain a resem-
blance to the proliferative glands of normal endometrium with
tall basophilic lining epithelium (Fig. 10.4). Variable amounts
Fig. 10.5 Serous adenocarcinoma of endometrium. Uterus, histologic
section (H&E x HP). Note the solid epithelial papillae, slit-like gland lumina,
and high-grade cytologic atypia.
Fig. 10.6 Clear cell carcinoma of the endometrium. Uterus, histologic
section (H&E x HP). Note the epithelial multilayering, marked cytologic atypia,
and abundant clear cytoplasm.
of squamous differentiation, previously called "metaplasia,"
are present. Elongated, slender papillae of adenocarcinoma
("villoglandular") lined by stratified columnar epithelium with
pencil-shaped nuclei are common. In contrast, the lumina of
the malignant glands of type II (serous and clear cell) adeno-
carcinomas show numerous internal papillae, many of which
consist of epithelium only. These papillae crowd into the lumen,
leaving only residual slit-like spaces (Fig. 10.5). Papillary fronds
of adenocarcinoma with a distinct central vascular connective
tissue stalk are common. Psammoma bodies may, or may not,
be present. In some cases, solid sheets or trabeculae may pre-
dominate. There is striking nuclear atypia of the lining epithe-
lium, often characterized by an open chromatin pattern with a
large nucleolus. Clear cell carcinomas share these features, but
in addition the cytoplasm is clear as a result of the accumulation
of glycogen (Fig. 10.6).
The grading of type I adenocarcinomas is based upon their
degree of resemblance to the normal endometrium, and is based
largely upon the extent of solid, or undifferentiated areas within
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