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ovarian cellular fibroma

Tuesday 9 July 2013

PO

See also : ovarian fibroma

Ovarian fibroma is the commonest benign tumor of the ovarian stroma. The cellular subtype accounts for around 10% of ovarian fibromatous tumors. The cellular fibroma is a tumor of uncertain malignant potential that may recur or be associated with peritoneal implants. Usually these are solid tumors, sometimes with small areas of cystic degeneration.

Ovarian fibroma is the commonest benign tumor of the ovarian stroma (4% of all ovarian neoplasms), and it can occur at any age.

The cellular subtype, approximately 10% of ovarian fibromatous tumors, exhibit hypercellularity, increased mitotic activity, and mild-to-moderate nuclear atypia.

The cellular fibroma is a tumor of uncertain malignant potential that may recur or be associated with peritoneal implants.

The degree of mitotic activity is the main parameter for differentiating cellular fibroma from fibrosarcoma.

Fibrosarcomas usually exhibit moderate-to-severe nuclear atypia and mitotic counts of 4 or more per 10 high-power fields (HPFs).

Macroscopically, the cellular fibroma has a whitish appearance resembling uterine leiomyoma, a generally solid consistency and, sometimes, small areas of cystic degeneration and stromal edema.

Clinically, it is asymptomatic and may typically be detected during routine gynecological examinations. Its behavior is usually benign, but the completeness of excision and presence or absence capsule rupture are important prognostic parameters.

Microscopy

- cellular intersecting bundles of spindle cells with bland nuclei
- less than 4 MF/10 HPF

Differential diagnosis

- classic ovarian fibroma
- ovarian fibrosarcoma

  • severe nuclear atypia
  • 4+ MF/10 HPF
  • aggressive clinical course

- diffuse adult granulosa cell tumor

  • Ovarian cellular fibromas are uncommon neoplasms, which may result in considerable diagnostic confusion with diffuse adult granulosa cell tumor.
  • This is an important distinction, as the former usually exhibits benign behavior, whereas the latter is a low-grade malignant neoplasm capable of recurrence and metastasis.
  • FOXL2 mutation (402C→G) has been demonstrated in >95% of ovarian adult granulosa cell tumors, only rarely in other ovarian sex cord-stromal neoplasms, and never in ovarian fibromas.
  • FOXL2 mutation analysis is a useful adjunct in distinguishing between diffuse adult granulosa cell tumor (mutation present) and cellular fibroma (mutation absent).
  • Mutation testing should be considered in problematic cases, as this will provide prognostic information for the patient.

Open references

- https://www.hindawi.com/journals/crim/2012/283948/

Paywall References

- Ovarian Cellular Fibromas Lack FOXL2 Mutations: A Useful Diagnostic Adjunct in the Distinction From Diffuse Adult Granulosa Cell Tumor. McCluggage WG, Singh N, Kommoss S, Huntsman DG, Gilks CB. Am J Surg Pathol. 2013 Jun 14. PMID: 23774170