Orbital Solitary Fibrous Tumour

Orbital Solitary Fibrous Tumour (SFT) is an uncommon benign spindle cell tumour with characteristics of mesenchymal fibroblast- like cells. It was originally recognised in the pleura. It is also seen in peritoneum, mediastinum, deep soft tissues of extremities, and conjunctiva as well.

Orbital solitary fibrous tumour in orbit may involve intraconal or extraconal compartment, lacrimal sac, lacrimal gland fossa, and eyelids. Orbital SFT was misdiagnosed until its characteristic features, particularly strong and diffuse immune-reactivity to CD 34 (cluster of differentiation 34 is a marker for primitive blood and bone marrow derived progenitor cells) was described. It is possible that orbital SFTs were under diagnosed earlier because of its rarity in extra-pleural sites and histological similarity to other spindle-cell tumours.

WHO in 2002 considered that SFTs, haemangiopericytomas, and giant-cell angiofibromas, represent a spectrum of spindle-cell neoplasm, rather than distinct pathologic entities.

 

References

Lee WR. Ophthalmic Histopathology Second Edition. Springer-Verlag London 2002. P 388.

Fay Aaron, Dolman Peter J. DISEASES and DISORDERS of the ORBIT and OCULAR ADNEXA. Elsevier Inc. 2017. P 363- 365.

Shields Jerry A, Shields Carol L. Eyelid, Conjunctival, and Orbital Tumors- An Atlas and Textbook Second Edition. Lippincott Williams & Wilkins, a Wolters Kluwer business 2008. P 632.

Prasad Srinivasa R, Miller Frank H. Radiologic Clinics of North America- Imaging of Select Multisystem Disorders. Elsevier Inc. 2016. P 568- 569.

Garrity James A, Henderson John Warren, Cameron J Douglas. Henderson’s Orbital Tumors Fourth Edition. Mayo Foundation for Medical Education and Research- Lippincott Williams & Wilkins, a Wolters Kluwer business. 2007. P 69-71.

Selvakumar Ambika, Noronha Veena, Sundaram Padmaja Minakshi. Sankara Nethralaya Atlas of Imaging in Ophthalmology. Jaypee Brothers Medical Publishers (P) Ltd. 2014. P 280- 281.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3263171/

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4732263/

http://eyewiki.aao.org/Solitary_fibrous_tumor

http://www.ajnr.org/content/29/5/857

http://www.indianjcancer.com/article.asp?issn=0019-509X;year=2015;volume=52;issue=3;spage=396;epage=397;aulast=Rahman

 

SFT most commonly presents in middle-aged patients with symptoms such as

  • Gradual unilateral progressive proptosis.
  • Mass effect as non pulsatile tumour (predominantly in the superior part of orbit).
  • Diminution of vision.
  • Restriction of ocular movements.
  • Blepharoptosis.

It is usually not associated with features of pain or entrapment of nerves.

Recurrent tumours often invade surrounding soft tissue or bone, with possibility of spread into nasal sinuses or cranial cavities.

 

Orbital solitary fibrous tumour is an uncommon benign spindle cell tumour with ultra structural and immuno-histochemical characteristics of mesenchymal fibroblast like cells.

SFTs are presumed to arise from pluripotent mesenchymal stem cells that have the capacity to differentiate along endothelial, pericytic, or fibroblastic phenotypes, similar to normal angiogenesis. This may explain the presence of the characteristic haemangiopericytoma like vessels. Currently, there is no stain to identify specific lineage such as pericytic origin.

Orbital solitary fibrous tumour is unilateral and occurs in both adults and children. Patient generally presents with proptosis and displacement of eyeball due to mass effect. It usually show slow clinical course without vision loss or significant pain. It may occur supero-temporally and may simulate lacrimal gland tumour. It may simultaneously involve orbit and nasal cavity. Occasionally, SFT may be aggressive and can extend to the central nervous system. Malignant transformation and metastasis are rare.

 

Histopathology:

Histopathologically, morphology of SFTs varies from highly cellular vascular lesion to fibrous areas with less number of cells. Fibrous matrix contains broad bands of collagen. Characteristic haemangiopericytoma like vascular branching, which is characterised by bifurcating dilated blood vessels with perivascular fibrosis, may be present. There is poor correlation between morphology and malignant potential.

In most SFTs, immuno-histochemistry shows an intense reactivity for vimentin (protein seen in cells derived from mesenchyme), CD34 and CD99.

 

Imaging studies:

  • CT Orbit: CT orbit shows mild to moderately enhanced well circumscribed mass with or without remodelling of adjacent bone.
  • MRI: MRI shows intermediate intensity mass on T1-weighted images with moderate enhancement after gadolium. The mass may be hyper or hypo-intense on T2-weighted images. Dynamic contrast enhanced magnetic resonance angiography (MRA) shows hyper-vascular arterial phase blush. MRI is also used for post-operative follow-up of SFT.
  • Ultrasonography: On ultrasonography, tumours show low reflectivity with moderate attenuation.

 

Differential diagnosis

SFT needs to be differentiated from

  • Orbital haemangiopericytoma
  • Fibrous histiocytoma
  • Neurofibroma
  • Optic nerve sheath meningioma
  • Schwannoma
  • Orbital metastasis.

 

Complete surgical resection is the treatment of choice. Incomplete removal increases the risk of clinical recurrence of tumour. Therefore, close follow up is required in cases with suspected residual tumour. Adjunctive radiation therapy is used in highly cellular lesions.

Recurrent tumours may show features of malignancy and may metastasise.

  • PUBLISHED DATE : Jun 20, 2018
  • PUBLISHED BY : NHP Admin
  • CREATED / VALIDATED BY : Dr. S. C. Gupta
  • LAST UPDATED ON : Jun 20, 2018

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