Ovary

Sex cord stromal tumors

Fibroma


Editorial Board Member: Ricardo R. Lastra, M.D.
Deputy Editor-in-Chief: Jennifer A. Bennett, M.D.
Gulisa Turashvili, M.D., Ph.D.

Topic Completed: 16 March 2021

Minor changes: 27 May 2021

Copyright: 2002-2021, PathologyOutlines.com, Inc.

PubMed Search: Fibroma[TI] ovary[TIAB] "last 10 years"[dp]


Gulisa Turashvili, M.D., Ph.D.
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Cite this page: Turashvili G. Fibroma. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/ovarytumorfibroma.html. Accessed October 23rd, 2021.
Definition / general
  • Benign stromal tumor composed of fibroblastic cells within a variably collagenous stroma
Essential features
  • Benign stromal tumor composed of spindled, ovoid to round cells within a variably collagenous stroma
  • Variants include fibroma with minor sex cord elements, cellular fibroma and mitotically active cellular fibroma
  • Important differential diagnoses for cellular fibroma include diffuse adult type granulosa cell tumor and fibrosarcoma
  • Gorlin syndrome should be suspected in young patients with bilateral ovarian fibroma
  • Long term follow up is recommended for cellular fibromas associated with rupture and adhesions due to increased risk of recurrence
ICD coding
  • ICD-O: 8810/0 - fibroma, NOS
  • ICD-10: D27 - benign neoplasm of ovary
  • ICD-11: 2F32.1 - ovarian fibroma
Epidemiology
  • Most common ovarian stromal tumor
    • ~4% of all ovarian tumors (Cancer 1981;47:2663)
    • Cellular fibromas represent ~10% of all ovarian fibromas
  • Mean age 48 years, uncommon before 30
  • Occurs in ~25% of patients with nevoid basal cell carcinoma syndrome (Gorlin syndrome) (J Med Genet 1993;30:460)
    • Autosomal dominant disease due to mutations of the human homologue of the Drosophila gene PTCH (patched)
Sites
  • Ovary
Pathophysiology
Clinical features
Diagnosis
  • Histologic examination for definitive diagnosis
  • Tentative diagnosis can be made grossly and at frozen section evaluation (Semin Diagn Pathol 2002;19:237)
Laboratory
Radiology description
  • Ultrasonography:
    • Usually solid, homogeneous and hypoechoic mass with posterior acoustic shadowing, similar to a pedunculated subserosal uterine leiomyoma (AJR Am J Roentgenol 1985;144:1239)
    • Heterogeneous echogenicity in tumors with necrosis, hemorrhage or cystic degeneration
  • Computed tomography:
    • Slightly hypoattenuating solid mass with poor, very slow contrast enhancement (Radiographics 2002;22:1305)
    • Rarely calcifications
  • Magnetic resonance imaging (MRI):
    • T1: homogeneous low signal intensity
    • T2:
      • Well circumscribed mass with low signal intensity (J Magn Reson Imaging 1997;7:465)
      • Hyperintense areas due to edema or cystic degeneration
      • Characteristic feature is a band of T2 hypointensity separating the tumor from the uterus on all imaging planes
    • Gadolinium: heterogeneous enhancement
    • May mimic malignancy (Radiographics 2002;22:1305)
Radiology images

Images hosted on other servers:
Bilateral ovarian fibroma on MRI

Bilateral ovarian fibroma on MRI

Unilateral ovarian fibroma on MRI

Unilateral ovarian fibroma on MRI

Prognostic factors
  • Excellent in most cases
  • Ovarian surface involvement and extraovarian adhesions occur in 6% of cellular fibromas and 10% of mitotically active cellular fibromas (Am J Surg Pathol 2006;30:929)
  • Extraovarian spread at surgery in 11% of cellular fibromas and 13% of mitotically active cellular fibromas (Am J Surg Pathol 2006;30:929)
  • Cellular fibromas may recur, often after a long interval, warranting long term follow up (Cancer 1981;47:2663)
Case reports
Treatment
  • Surgical excision (salpingo-oophorectomy, oophorectomy or ovarian sparing procedure with or without hysterectomy depending on patient’s age)
  • Cellular fibromas require long term follow up, particularly in the setting of ovarian surface involvement, intraoperative rupture or extraovarian spread (Cancer 1981;47:2663)
Gross description
  • Well circumscribed mass with smooth, lobulated surface
  • Firm, chalky, solid, white to yellow-white to tan-yellow cut surface that may be whorled
  • Frequent edema resulting in softer consistency
  • Mean size 6 cm (range 1 - 21.5)
  • Usually unilateral (< 10% bilateral)
  • Cystic degeneration in ~25% of cases
  • Calcifications in ~10% of cases
  • ~20% present as pedunculated or polypoid growths on ovarian surface
  • With or without hemorrhage or necrosis
  • Cellular fibroma:
    • Mean size 8 - 9 cm (range 1 - 19)
    • Tan-yellow, soft and fleshy cut surface (Cancer 1981;47:2663)
    • With or without surface adhesions
  • Fibroma associated with Gorlin syndrome:
Gross images

Contributed by Rex Bentley, M.D. and AFIP images

Chalky white surface

Edematous and focally hemorrhagic

Dense white mass



Images hosted on other servers:
Fibroma

Hard white tumor

Fibrothecoma

Fibrothecoma

Frozen section description
  • Variably cellular spindle cell neoplasm with fascicular or storiform growth with or without hyaline plaques or calcifications
Frozen section images

Contributed by Gulisa Turashvili, M.D., Ph.D.

Spindle cell neoplasm

Bland spindle cells

Microscopic (histologic) description
  • Conventional fibroma:
    • Recapitulates ovarian cortex
    • Usually well circumscribed but nonencapsulated
    • Variably cellular fascicular or less frequently, storiform growth of tumor cells within a variably collagenous stroma, sometimes with hyaline plaques (Cancer 1981;47:2663)
    • Bland spindled to ovoid nuclei with pointy ends and scant eosinophilic cytoplasm blending with surrounding stroma
    • Occasional mitoses (usually up to 3 mitoses per 10 high power fields)
    • With or without Verocay-like areas (slightly wavy, parallel arrays of spindled nuclei), calcification, edema, hemorrhage, infarct type necrosis, rare groups of luteinized cells
    • Rarely intracytoplasmic lipid (may be diagnosed as thecoma), eosinophilic hyaline globules, melanin pigment or bizarre nuclei (Int J Gynecol Pathol 2009;28:356, Int J Gynecol Pathol 2019;38:92, Int J Surg Pathol 2020 [Epub ahead of print])
  • Cellular fibroma (10% of cases):
    • Resembles diffuse type of adult granulosa cell tumor
    • Densely cellular with little intercellular collagen
    • Bland spindled nuclei with up to 3 mitoses per 10 high power fields (Cancer 1981;47:2663)
    • "Mitotically active cellular fibroma" has been proposed for cellular fibromas with ≥ 4 mitoses per 10 high power fields (Am J Surg Pathol 2006;30:929)
  • Fibroma with minor sex cord elements:
    • Sex cord component accounting for < 10% of overall tumor volume
    • No prognostic significance
Microscopic (histologic) images

Contributed by Gulisa Turashvili, M.D., Ph.D., Kyle C. Strickland, M.D., Ph.D. and Rex Bentley, M.D.
Cellular spindle cell neoplasm

Cellular spindle cell neoplasm

Mild cytologic atypia

Mild cytologic atypia

Mitotic activity

Mitotic activity

Small tubules

Small tubules

Variable cellularity


Bland spindle cells

Spindled to ovoid nuclei

Dense collagen

Cellular spindle cell neoplasm


Reticulin

Reticulin

Inhibin Inhibin

Inhibin

Calretinin

Calretinin

Virtual slides

Images hosted on other servers:

Fibroma (conventional)

Reticulin stain in fibroma

Cellular fibroma

Reticulin stain in cellular fibroma


Fibroma (conventional)

Calretinin stain

Inhibin stain

Positive stains
Electron microscopy description
  • Numerous thin, elongated cells with intercommunicating cytoplasmic processes admixed with abundant collagen fibrils (Cancer 1971;27:438)
    • Fibrils appear grouped in bundles with a crossbanding pattern composed of a light band bound by two thin dark bands (recurring at intervals of 600 Å)
    • Cells have indistinct cell borders and are compressed by collagenous stroma
    • Elongated and thin nuclei with marked peripheral heterochromatin condensation
    • Scant cytoplasm containing few mitochondria and scant endoplasmic reticulum
Molecular / cytogenetics description
Sample pathology report
  • Right ovary and fallopian tube, salpingo-oophorectomy:
    • Ovary: fibroma
    • Fallopian tube: unremarkable
Differential diagnosis
Board review style question #1

Microscopic examination of an 8 cm unilateral ovarian mass demonstrates a densely cellular neoplasm composed of intersecting fascicles of spindle cells with mild cytologic atypia and approximately 9 mitotic figures per 10 high power fields. Reticulin staining shows pericellular staining pattern and molecular testing is negative for FOXL2 mutation.

What is the most likely diagnosis?

  1. Fibroma
  2. Fibrosarcoma
  3. Leiomyoma
  4. Leiomyosarcoma
  5. Mitotically active cellular fibroma
Board review style answer #1
E. Mitotically active cellular fibroma

Comment Here

Reference: Fibroma
Board review style question #2
You receive an intraoperative consultation for bilateral multinodular ovarian masses in a 16 year old patient. Microscopic examination demonstrates bland, monomorphic spindled cells within a collagenous stroma.

Mutation of which of the following genes is most likely associated with this entity?

  1. FOXL2
  2. HMGA2
  3. JAZF1
  4. PTCH
  5. Vimentin
Board review style answer #2
D. PTCH. Bilateral ovarian fibroma in a young patient is most likely associated with Gorlin syndrome.

Comment Here

Reference: Fibroma
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