Ovary

Sex cord stromal tumors

Sclerosing stromal tumor

Editor-in-Chief: Debra L. Zynger, M.D.

Topic Completed: 17 December 2019

Minor changes: 28 June 2021

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PubMed search: Ovarian sclerosing stromal tumor (free full text[sb])

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Table of Contents

Cite this page: Bennett J. Sclerosing stromal tumor. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/ovarytumorsclerosingstroma.html. Accessed October 17th, 2021.

Definition / general

Sclerosing stromal tumor (SST) is a benign stromal tumor with a pseudolobular appearance resulting from alternating cellular and hypocellular areas

Essential features

Alternating cellular and hypocellular areas impart a pseudolobular appearance
Pseudolobules contain a haphazard arrangement of epithelioid (lutein) and spindled cells
Hemangiopericytoma-like vessels conspicuous in both components
Positive for sex cord markers but negative for EMA and cytokeratin

ICD coding

ICD10: D27.9 - benign neoplasm of unspecified ovary
ICD-0 : 8590/1 C56 - sex cord gonadal stromal tumor, NOS

Epidemiology

Most present at < 30 years (range: 7 months to 80 years)

Sites

Ovary

Pathophysiology

Unknown

Clinical features

Most present with menorrhagia or abdominopelvic pain
Typically nonfunctioning but virilization or precious puberty may occur
Rare associations with Meigs syndrome (Eur J Gynaecol Oncol 2004;25:528, J Obstet Gynaecol 2010;30:747)

Diagnosis

Mass is observed on imaging
Diagnosis is made by histological examination of an ovarian resection specimen

Laboratory

CA-125 often within normal limits but elevated levels have been reported (Eur J Gynaecol Oncol 2017;38:326)

Radiology description

CT
- Plain: nonhomogeneous density
- Contrast: peripheral ring enhancement, may see enhancement of central patch or internal septa
- Venous phase: enhancement decreases but increases with centripetal progression, no enhancement of cystic component (Oncol Lett 2016;11:3817)
MRI
- T1 weighted: slight hyperintense periphery, irregular hypointense center
- T2 weighted: hyperintense cystic components or heterogeneous solid mass with intermediate to high intensity
- T1 with contrast: early peripheral enhancement with centripetal progression (AJR Am J Roentgenol 2005;185:207)

Radiology images

Images hosted on other servers:

CT ovarian mass

MRI ovarian mass

Prognostic factors

Benign prognosis

Case reports

14 year old girl with primary amenorrhea (Case Rep Radiol 2015;2015:271394)
18 year old woman with irregular menses (Int J Surg Case Rep 2015;9:72)
20 year old woman with pelvic pain (BMJ Case Rep 2016;2016:bcr2015214101)
24 year old woman with menstrual irregularities and lower abdominal pain (Iran J Pathol 2017;12:402)
80 year old woman with incidental pelvis mass discovered on ultrasound (J Menopausal Med 2014;20:80)

Treatment

Surgical excision (oophorectomy)

Clinical images

Images hosted on other servers:

Laparoscopy

Large mass

Gross description

Typically unilateral and well circumscribed, ranging from 1.5 to 17 (mean 11) cm
Gray-white-yellow solid mass often with a single large cyst or multiple small cysts
Texture ranges from firm and rubbery to edematous and myxoid / mucoid
Hemorrhage, calcifications and rarely necrosis may be seen (Cancer 1973;31:664)

Gross images

Contributed by Jennifer Bennett, M.D.

Yellow-white mass

Frozen section description

Mass with notable cellular and hypocellular regions, pseudolobules, staghorn vessels and minimal cytologic atypia are helpful in excluding primary epithelial ovarian malignancies
- Caveat cellular and hypocellular regions with pseudolobules may be seen in Krukenberg tumors, so carefully examine for incipient metastases

Frozen section images

Contributed by Jennifer Bennett, M.D.

Alternating cellularity

Cellular pseudolobule

Microscopic (histologic) description

Alternating cellular and hypocellular areas impart a pseudolobular appearance (Cancer 1973;31:664)
- Hypocellular foci may be ill defined in pregnancy due to expansion of the pseudolobules by lutein cells (Int J Gynecol Pathol 2015;34:357)
Thin, dilated and branching hemangiopericytoma-like vasculature are often conspicuous in both components
Pseudolobules comprised of a jumbled admixture of epithelioid (lutein) and spindled cells with minimal atypia (Cancer 1973;31:664)
- Epithelioid cells: round nuclei with prominent nucleoli, vesicular chromatin and clear to vacuolated cytoplasm
  - Abundant eosinophilic cytoplasm often seen in pregnancy (Int J Gynecol Pathol 2015;34:357)
  - Occasionally have a signet ring-like appearance
- Spindled cells: elongated nuclei with indistinct nucleoli, bland chromatin and scant eosinophilic cytoplasm
- Typically round to ovoid but may show angulation if edema is striking
Hypocellular areas can be edematous, collagenous (+/- keloid-like) or myxoid
Mitoses often inconspicuous but rarely can number up to 12/10 high power fields, no atypical forms (Int J Gynecol Pathol 2016;35:549)
Infarct type necrosis and calcification infrequent

Microscopic (histologic) images

Contributed by Jennifer Bennett, M.D.

Alternating cellularity

Pseudolobule

Collagenous background

Abundant eosinophilic cytoplasm

Inhibin

Positive stains

Sex cord markers inhibin, calretinin, SF1, FOXL2
ER, PR, CD10, Vimentin, smooth muscle actin
Diffuse TFE3 expression in a subset of tumors (Anticancer Res 2017;37:5441)

Negative stains

Cytokeratin, EMA

Electron microscopy description

3 cell types (Int J Gynecol Pathol 1988;7:280):
- Epithelioid cells: membrane bound cytoplasmic lipid, well developed Golgi
- Spindled cells: fibroblast-like, prominent rough endoplasmic reticulum
- Undifferentiated primitive mesenchymal cells (in hypocellular areas): few organelles, rare cilia and basal lamina
- Smooth muscle differentiation supported by aggregates of cytoplasmic filaments with interspersed dense bodies, pinocytotic vesicles and basal lamina (Ultrastruct Pathol 1992;16:363)

Molecular / cytogenetics description

Trisomy 12 has been reported in a subpopulation of cells (Am J Surg Pathol 1998;22:83, Eur J Gynaecol Oncol 2004;25:257, Pediatr Dev Pathol 2008;11:300)

Sample pathology report

Right ovary, oophorectomy:
- Sclerosing stromal tumor (5.0 cm)

Differential diagnosis

Thecoma (Am J Surg Pathol 2014;38:1023)
- Typically postmenopausal
- Estrogenic manifestations in 50%
- Staghorn vessels absent
- No admixture of cells
Steroid cell tumor
- Hormonal manifestations in 50%
- Staghorn vessels absent
- No admixture of cells
Fibroma
- Peri- or postmenopausal
- Often have a uniform white cut surface
- Staghorn vessels absent
- No pseudolobules
Metastatic signet ring cell carcinoma (Krukenberg tumor) (Am J Surg Pathol 2006;30:277)
- Bilateral in > 50%, often with extraovarian disease at presentation
- Staghorn vessels absent
- Admixed with glands, nests or cords of malignant cells (may be very focal)
- Cytokeratin strongly and diffusely positive
Pregnancy luteoma
- Often bilateral and multifocal
- Brown and hemorrhagic cut surface
- No admixture of cells
Solitary fibrous tumor (Histopathology 2018;72:749)
- Patternless architecture
- Epithelioid cells absent
- STAT6 typically strong and diffuse (while may be weak and focal in sclerosing stromal tumor)
- Inhibin negative

Board review style question #1

Pregnancy luteoma
Sclerosing stromal tumor
Solitary fibrous tumor
Steroid cell tumor
Thecoma

Board review style answer #1

B. Sclerosing stromal tumor

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Reference: Sclerosing stromal tumor

Board review style question #2

It is characterized by a recurring fusion
It is only seen in pregnancy
It is typically white, firm and uniform on cut surface
Marked cytologic atypia, tumor cell necrosis and atypical mitoses are common
The cellular foci are composed of lutein and spindled cells

Board review style answer #2

E. The cellular foci are composed of lutein and spindled cells. This is an ovarian sclerosing stromal tumor.

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Reference: Sclerosing stromal tumor