Ovary
Sex cord stromal tumors
Sclerosing stromal tumor

Editor-in-Chief: Debra Zynger, M.D.
Jennifer Bennett, M.D.

Topic Completed: 17 December 2019

Minor changes: 17 December 2019

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

Jennifer Bennett, M.D.
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Cite this page: Bennett J. Sclerosing stromal tumor. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/ovarytumorsclerosingstroma.html. Accessed September 23rd, 2020.
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
Diagnosis
  • Mass is observed on imaging
  • Diagnosis is made by histological examination of an ovarian resection specimen
Laboratory
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

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CT ovarian mass

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MRI ovarian mass

Prognostic factors
  • Benign prognosis
Case reports
Treatment
  • Surgical excision (oophorectomy)
Clinical images

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Laparoscopy

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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.
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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.
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Alternating cellularity

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Cellular pseudolobule

Microscopic (histologic) description
  • Alternating cellular and hypocellular areas impart a pseudolobular appearance (Cancer 1973;31:664)
  • 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
    • 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.
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Alternating cellularity

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Pseudolobule

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Collagenous background

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Abundant eosinophilic cytoplasm

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Inhibin

Virtual slides

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Sclerosing stromal tumor

Positive stains
Negative stains
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
Sample pathology report
  • Right ovary, oophorectomy:
    • Sclerosing stromal tumor (5.0 cm)
Differential diagnosis
Board review style question #1
    A 30 year old woman presented with pelvic pain; ultrasound detected a 10 cm mass in the left ovary. She underwent oophorectomy and you receive an intact specimen with a 10 cm well circumscribed yellow-white, edematous lesion with multiple cysts that replaces the entire ovary. Histologic examination shows cellular areas that alternate with hypocellular edematous foci. Staghorn vessels are prominent. What is the likely diagnosis?

  1. Pregnancy luteoma
  2. Sclerosing stromal tumor
  3. Solitary fibrous tumor
  4. Steroid cell tumor
  5. Thecoma
Board review answer #1
B. Sclerosing stromal tumor

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Reference: Sclerosing stromal tumor
Board review style question #2

    Which of the following is true regarding the ovarian lesion pictured above?

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