Fibroma-Thecoma
Epidemiology and Etiology:
- Thecoma:
- Mean 59 years
- 84% postmenopausal
- Rare before puberty, uncommon before 30 y.
- Association with endometrial carcinoma (~20% of
thecomas in post-menopausal women)
- Fibroma:
- Mean 48 years
- Middle age frequently but occurs at all ages
Common sites:
Gross features:
- Thecoma:
- Unilateral in 97%
- 5-10 cm but range in size
- Solid yellow mass typically
- Focal tinges of yellow in some cases
- Cystic changes maybe
- Hemorrhage foci maybe
- Necrosis maybe
- Fibroma:
- Variable size
- Hard, flat, chalky-white whorled cut surfaces
- Edematous areas common
- Cyst formation occasionally
- Calcification, focal or diffuse (< 10%)
(associated with basal cell nevus syndrome)
- unilateral in 90%
- solid, spherical, or slightly lobulated
- encapsulated
- hard, gray-white
- covered with glistening ovarian serosa
Histologic features:
- thecoma:
- masses of cells
- fibrous bands or hyaline plaques intersecting
cell masses
- ill-defined cell borders
- oval or rounded cells with moderate to abundant
cytoplasm
- pale or dull grey cytoplasm
- vacuolated cytoplasm in some cases
- round to spindled nuclei
- little or no atypia
usually
- mitoses absent or infrequent
- myxoid stroma maybe
- calcified rarely
- crystals of Reinke
rarely (stromal-Leydig cell tumour) (half are virilizing)
- features associated with potentially fatal sclerosing peritonitis:
- bilateral (nearly always)
- irregular ovarian enlargement, often resulting
in a striking expansion of the cortex and an exaggerated cerebriform appearance, suggesting a nonneoplastic process in some cases
- dense cellular areas and less cellular areas in which edema with microcystic change is often conspicuous.
- Lutein cells smaller and less easy to recognize
- Incorporated preexisting ovarian structures
such as follicles, frequently
- Brisk mitotic activity in many cases
- Luteinized cells stain with inhibin
and calretinin, but spindle cell component
typically negative
- Sclerosing peritonitis associated (nearly always), may cause significant
morbidity
- Fibroma:
- Intersecting bundles of spindle cells producing
collagen
- Storiform pattern maybe
- Bands of hyalinized
fibrous tissue not uncommon
- Intercellular edema maybe
- Small quantities of lipid maybe
- Small red granules in cytoplasm rarely
- Minor component of sex cord elments
occasionally
- Cellular fibroma:
- Intensely cellular
- Mitotic activity may be relatively brisk (>
4 / 10 HPF)
- Cytologic atypia not significant
- Alternating cellular and less cellular areas
- Features of fibrosarcoma:
- Uniform hypercellularity
- Atypia significant
- Mitotic activity conspicuous
- No rigid criteria to distinguish from cellular
fibroma
- composed of a mixture of well-differentiated
fibroblasts (looks pink on low-power) and more plump spindle cells with
lipid droplets (thecal cells) (looks blue on
low-power)
- scant collagenous connective tissue interspersed
between cells
- luteinized theca / stroma cells in some
(luteinized thecomas)
- commonly has dystrophic calcifications
Immunophenotype:
Marker:
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Sensitivity:
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Specificity:
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Molecular features:
Other features:
- Uterine bleeding
- Thecoma:
- Nearly always benign
- Adequately treated by oophorectomy
- For post-menopausal patients, TAH-BSO is
indicated
- most are composed mostly of fibroblasts and are
hormonally inactive
- tumours
with luteinized cells (steroid cells) may be hormonally active
- estrogenic usually
- androgenic sometimes (with virilization)
- fibroma:
- associated with ascites (40%) in larger tumours (>6cm)
- uncommonly, hydrothorax (usually right)
- association with basal cell nevus syndrome
References:
- ?Robbins
- Blaustein
(2011)