Hemangiopericytoma

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Hemangiopericytoma is a rare mesenchymal tumor, typically located in the retrobulbar intrazonal space of the orbit, that is generally slow-growing, but has malignant potential.

Disease Entity

Incidence

Hemangiopericytoma is most commonly encountered in the orbit, but can be located in the conjunctiva, choroid, optic nerve or medial canthal skin. Hemangiopericytoma makes up 1-3% of all biopsied orbital lesions[1] and 1% of all lacrimal sac tumors[2]. The mean age of onset of orbital hemangiopericytoma is 42 years, however lacrimal sac hemangiopericytoma has a slightly earlier age on onset[2]. Hemangiopericytoma affects males and females equally and no racial differences have been observed[3].


Classification

Controversy exists regarding the diagnosis of orbital hemangiopericytoma as it shares many characteristics with fibrous histiocytoma and giant cell angiofibroma of the orbit. Some pathologists recommend classifying all three tumors as solitary fibrous tumors[4].


General Pathology

Cells in hemangiopericytomas are derived from pluripotent perivascular mesenchymal cells and resemble pericytes, with few cytoplasmic organelles[2]. Thin-walled, branching blood vessels, also known as “staghorn” vessels, are characteristic of hemangiopericytomas. Nuclei are often ovoid or spindle shaped[4]. The masses are generally well-circumscribed or encapsulated (75%)[3]. Hemangiopericytomas uniformly stain positively for CD34 and vimentin [2][4]. 70% are Leu-7 positive. Factor XIIIa and HLA-DR may also be present in some hemangiopericytomas[3].

30% of orbital hemangiopericytomas are histologically compatible with malignancy. Findings that indicate a worse prognosis include high mitotic rate, increased cellularity, pleomorphism, necrosis and hemorrhage[3]. Other prognostic markers include Bcl-2, p53 and Ki-67[4].

Diagnosis

History and Clinical Presentation

Clinical presentation varies significantly, with the most common presenting complaint of a painful or painless orbital mass. Patients may present with proptosis, diplopia, orbital pressure or pain[5] [6]. Patients with lacrimal sac hemangiopericytomas may present with a painless mass near the medial canthus. They may also present with epiphora, which may be bloody. Subconjunctival hemangiopericytoma is rare, however case studies have identified patients presenting with visible masses and subconjunctival bleeding after sneezing.

Physical examination

Orbital hemangiopericytomas occur most frequently in the superior orbit, equally distributed between the medial and lateral orbit. Masses may be visible on exam if located in the subconjunctival space or lacrimal sac. Lacrimal masses tend to be ballottable on palpation. Vision may be decreased, proptosis may be measured on exophthalmometry, and motility may be limited depending on the size and location of the mass.

Clinical diagnosis

Diagnostic procedures

Further diagnostic testing may include CT or MRI imaging of the lesion to delineate anatomical relationships for surgical planning[7]. Radiology typically demonstrates a well-circumscribed, round, retrobulbar mass, often within the muscle cone, although it can be located extraconally. However, definitive diagnosis requires histopathologic evaluation of the lesion. If metastases are clinically suspected, workup should include relevant imaging.

Differential diagnosis

Orbital mass

  • Fibrous histiocytoma
  • Hemangioma
  • Glomus tumor
  • Biphasic sarcomas
  • Synovial sarcoma
  • Kaposi’s sarcoma
  • Vascular malformation

Medial canthal mass

  • Fibrous histiocytoma
  • Lipoma
  • Lymphoid tumors
  • Melanoma
  • Granulocytic sarcoma
  • Neurofibroma
  • Neurilemoma
  • Squamous cell carcinoma

Management

Medical therapy

The role of chemotherapy is unclear in the treatment of hemangiopericytoma. Recent studies have shown limited benefit of preoperative ifosfamide and epirubicin[1]. Studies of preoperative radiation have also been inconclusive[1][3].

Medical follow up

A multidisciplinary management approach in conjunction with the primary care physician and oncologist is recommended.

Surgery

Definitive treatment for hemangiopericytoma is a complete local excision including the capsule. Excellent hemostasis is important intraoperatively due to the highly vascular nature of hemangiopericytomas. High-resolution CT/MRI or dynamic contrast-enhanced MRA (TRICKS) may be useful for the surgical planning of complex lesions[8].

Prognosis

Overall 5-year survival of orbital hemangiopericytomas has been reported as 89%. Local recurrences are relatively common, at 4-7% at 1 year and 15-33% at 5 years. A multidisciplinary management approach in conjunction with the primary care physician and oncologist is recommended. Metastases are relatively rare in orbital, subconjunctival and lacrimal hemangiopericytomas; however, metastases have been reported in the lung, liver, bone and mediastinum[2].

References

  1. 1.0 1.1 1.2 Shinder R, Jackson TL, Araujo D, Prieto VG, Guadagnolo BA, Esmaeli B. Preoperative radiation therapy in the management of recurrent orbital hemangiopericytoma. Ophthalmic Plastic and Reconstructive Surgery. 2011 Sep-Oct; 27(5): e126-8.
  2. 2.0 2.1 2.2 2.3 2.4 Charles N, Palu R, Jagirdar S. Hemangiopericytoma of the Lacrimal Sac. Archives of Ophthalmology. 1998; 116:1677-1680.
  3. 3.0 3.1 3.2 3.3 3.4 Sujatha S, Sampath R, Bonshek RE, Tullo AB. Conjunctival haemangiopericytoma. British Journal of Ophthalmology 1994; 78:497-499.
  4. 4.0 4.1 4.2 4.3 Furusato E, Valenzuela I, Fanburg-Smith J, Auerbach A, Furusato B, Cameron D, Rushing E. Orbital solitary fibrous tumor: encompassing terminology for hemangiopericytoma, giant cell angiofibroma and fibrous histiocytoma of the orbit: reappraisal of 41 cases. Human Pathology. January 2011; 42(1): 120-128.
  5. Croxtto J, Font R. Hemangiopericytoma of the orbit: A clinicopathologic study of 30 cases. Human Pathology. March 1982; 13(3): 210-218.
  6. Henderson JW, Farrow GM. Primary orbital hemangiopericytoma. An aggressive and potentially malignant neoplasm. Archives of Ophthalmology. 1978; 96(4): 666-73.
  7. Kikuchi K, Kowada M, Sageshima M. Orbital hemangiopericytoma: CT, MRI and angiographic findings. Computer Medicine Imaging Graph. 1994; 18(3): 217-22
  8. Kahana A, Lucarelli MJ, Grayev AM, Van Buren JJ, Burkat CN, Gentry LR. Noninvasive dynamic magnetic resonance angiography with time-resolved imaging of contrast kinetics (TRICKS) in the evaluation of orbital vascular lesions. Archives of Ophthalmology 2007;125(12):1635-1642
  1. Arshad AR, Normala BM. Infantile malignant hemangiopericytoma of the orbit. Ophthalmic Plastic and Reconstructive Surgery. 2008; 24(2): 147-148.