29
Pediatric Tumors
Rhabdomyosarcoma
Embryonary rhabdomyosarcoma is the most frequent inferior
genital tract malignancy in females; it is located frequently in the
vagina and sometimes in the vulva and uterus. Most rhabdomy-
osarcomas affect girls younger than 5 years with hemorrhagic
vaginal discharge, abdominal tumor, protrusion of a polypoid
tumor, and glistering at the vaginal introitus. Fine-needle aspi-
rates are described with soft tissue tumors.31
Tumors of the Ovary
Benign Tum ors
Benign Cysts
Benign cysts are the most frequent tumors in females and are
derived from ovarian follicles at different stages of matura-
tion. Many of them are ultrasonographic findings, and some-
times they can complicate with torsion and rupture, especially
those > 5 cm in diameter.31 Fine-needle aspirates are often acel-
lular or with scarce epithelial cells, which permit establishment
of the cyst's nature. Cortical inclusion and follicular cysts show
scarce sheets formed by small cubic cells with scarce cytoplasm
and small round nuclei with a thin chromatin, and ciliated cells
in paraovarian cysts. Cysts of the corpus luteus show large lutei-
nized cells with huge nuclei often with prominent nucleoli.32
For the key features of benign cysts, see Chapter 12
(Peritoneal
Washings and Ovary).
M alignant Tum ors
Malignant tumors account for 1% of all cancers in female chil-
dren, and histologic variants are different from those of adult
women. Most of them are from germ cells and celomic epithe-
lia, and some of them from sexual stroma cords. They often
affect girls between 10 and 14 years and manifest with abdomi-
nal pain, occasionally simulating an acute abdomen.31
G erm Cell Tumors
Germ cell tumors are frequent in girls, affecting mostly post-
pubertal children, but they are very rare in younger girls. They
include mature and immature teratomas, malignant germ cell
tumors, and digenetic gonad tumors.31
M ature Teratoma
Mature teratomas are benign and contain disordered mature tis-
sues of one or more embryonic layers and account for 50% of
all ovarian neoplasms in girls; 10% are bilateral and most affect
patients between 13 and 15 years. The majority are cysts con-
taining fatty material and hairs (Fig. 29.8A), rarely with imma-
ture elements (Fig. 29.8B).31 Fine-needle aspirates show variable
amounts of amorphous material (sebum), corneous flakes and/
or squamous epithelial cells, inflammatory cells (sometimes
giant multinucleated with cytoplasmic refringent material), hair
fragments, and epithelial cells of sebaceous glands and respira-
tory and mature intestinal tissue (Fig. 29.8C).32
For the key features of mature teratoma, see Chapter 12.
Im m ature Teratoma
Immature teratomas are considered to be of intermediate malig-
nancy and rarely produce metastases. They are predominantly
solid, and they are histologically graded according to the amount
of immature elements, particularly immature neuroectoderm.
Occasionally, they develop a malignant component, generally
a yolk sac tumor, which produces high levels of AFP in serum.
Cytogenetic studies reveal a high frequency of chromosomal
anomalies (60% of cases).31 Fine-needle aspirates show small
undifferentiated atypical cells similar to those of neuroblastoma
and/or squamous epithelial cells or isolated atypical glandular
ones forming three-dimensional groups.32
D ysgerm inom a
Dysgerminoma is the most frequent malignant germ cell tumor
of the ovary. Dysgerminomas are generally solid and large with
a white surface and are plain or irregular. When dissected, they
look white and homogeneous and sometimes have necrotic
areas (Fig. 29.8D).
Microscopically,
dysgerminomas
are
very
cellular
and
formed by round cells with light cytoplasm and vesiculous
nuclei with prominent nucleoli and numerous mitoses; there
is little cellular cohesion, scarce stroma, often lymphocytic
infiltration, and sometimes giant multinucleated and cytotro-
phoblastic cells. Dysgerminomas can produce rises in levels
of chorionic gonadotrophin, and the majority are positive for
placental alkaline phosphatase (Fig. 29.8E).31 Fine-needle aspi-
rates are frequently very cellular and heterogeneous, with large
neoplastic cells, which are round and isolated with light cyto-
plasm and well-delimited and vesiculous nuclei with promi-
nent nucleoli, mixed with small lymphocytes and plasmocytes
(Fig. 29.8F).32
See the key features of dysgerminoma in Chapter 12.
Yolk Sac Tum or
Yolk sac tumor is the malignant germ cell tumor that follows
dysgerminoma in frequency. It grows quickly and arises as a
vaginal polypoid tumor and/or with hemorrhagic vaginal dis-
charge and high AFP levels. These tumors vary widely histologi-
cally and cytologically, which causes difficulties in establishing
the diagnosis. The majority of these tumors contain diverse sub-
types. Between 50 and 70% of cases show Schiller-Duval bodies
composed of a central vascular core lined by tumor cells, then
a space and a band of tumor cells.31 Fine-needle aspirates show
three-dimensional aggregates of columnar atypical cells, some-
times with hyaline bodies positive for PAS in the cytoplasm.32
See the key features of yolk sac tumor in Chapter 12.
Embryonary Carcinom a
Embryonary carcinoma is a rare germ cell tumor in girls.31 Fine-
needle aspirates are frequently very cellular; cells are similar to those
of dysgerminoma but with more severe atypias and arranged in
three-dimensional aggregates, pseudotubules, and papillae, which
recall the cytologic appearance of high-grade adenocarcinoma.32
Granulosa Cell Tum or
Granulosa cell tumor is a tumor derived from granulosa cells
and often occurs in children older than 10 years with preco-
cious puberty or virilization. Granulosa cell tumors are solid or
solid cystic and often have yellow areas separated by gray bands.
Microscopically, they are different from those of adults, showing
a complex pattern, with nodules or luteinized cells and some-
times with follicles with PAS-positive material; stroma is fibrous
and sometimes shows pale cells with lipids and oval to elliptic
cells with light eosinophilic cytoplasm.31 Fine-needle aspirates
show sheets of medium-sized round cells with wide cytoplasm
933
previous page 921 ComprehensiveCytopathology 1104p 2008 read online next page 923 ComprehensiveCytopathology 1104p 2008 read online Home Toggle text on/off