Fibrous Histiocytoma

Etiology

• Arises from mesenchymal cells in fascia, muscle, or other soft tissues
• Orbit is the most commonly affected periocular structure
• Conjunctiva and eyelids can also be involved.

Epidemiology

• Three main subtypes. based on clinical behavior
• Benign 63%
• Locally aggressive 26%
• Malignant 11%
• A rare tumor, however the most common mesenchymal tumor of the orbit
• Most common in adults 30–60 years old
• 3%–10% occur in pediatric population; can occur following external beam radiation for retinoblastoma (Shields, Ophthal Plast Reconstr Surg. 2001)
• Male = female
• Some authors have suggested that fibrous histiocytoma refers specifically to fibroblastic spindle cell tumors of the orbit with aggressive behavior and have advocated re-classifying more superficial, benign lesions as dermatofibromas (Tieger, Ophthal Plast Reconstr Surg. 2019).

History

• Decreased vision
• Progressive proptosis
• Diplopia
• Previous history of FH

Clinical features

• Proptosis
• Dystopia
• Lid swelling
• Loss of vision
• Afferent pupillary defect due to compressive optic neuropathy
• Decreased motility
• Ptosis
• Chemosis
• Ephiphora and dacryocystitis if there is extension into the lacrimal sac (Stefanyszyn, Ophthal Plast Reconstr Surg. 1994)
• Most commonly occur supranasally, however can occur anywhere in the orbit and periorbital sctructures
• FH reportedly can occur in the lacrimal gland (Bajaj, Ophthal Plast Reconstr Surg. 2007)

Testing

Evaluation of motility, vision, pupils, Hertel exophthalmometry

Computed tomography

• Typically well circumscribed, but can be irregular
• Similar in appearance to schwannomas or cavernous hemangiomas
• Bone erosion is rare, but can be seen in recurrences or malignant lesions.

Magnetic resonance imaging

• T1
• Heterogenous
• Isointesnse to slightly hyperintense to muscle, hypointense to fat
• T2: Collagenous regions appear hypointense, whereas cellular areas are hyperintense.
• Heterogenous enhancement with gadolinium

Positron emission tomography

• Useful in detecting metastases as well as deciphering a recurrence from post-surgical changes (Char, Orbit. 2000)

Histopathology

• Benign:
• Poorly defined margins
• Spindle-shaped fibroblasts with a storiform pattern
• Can have vascular areas that are indistinguishable from hemangiopericytomas
• Locally aggressive
• Infiltrative margins
• Hypercellular
• Mitotic figures
• Malignant
• Infiltrative margins
• Nuclear pleomorphisms
• Atypia
• Necrosis
• Multinucleated giant cells
• Immunohistochemical staining
• Vimentin
• Alpha-antitrypsin
• Factor XIIIA
• Smooth muscle actin
• CD68

Figure 1. Completely excised fibrous histiocytoma.

Risk factors

• Middle aged adults

• Cavernous hemangioma
• Hemangiopericytoma
• Schwannoma
• Solitary Fibrous tumor

Natural history

(Font, Hum Pathol. 1982.)

• 63% are benign, 26% are locally aggressive, and 11% are malignant.
• Recurrence:
• Benign: 31%
• Locally aggressive: 57%
• Malignant: 64%
• 10-year survival rates:
• Benign: 100%
• Locally aggressive: 92%
• Malignant: 23%

Medical therapy

• Radiation has been shown to be ineffective, and has even been reported to induce formation of malignant FH (Zhang, World J Surg Oncol. 2014; Shields, Ophthal Plast Reconstr Surg. 2001)
• Adjunctive chemotherapy

Surgery

• Local Excision for well-circumscribed lesions
• Locally invasive and malignant lesions often require a wide surgical excision.
• Malignant recurrences and aggressive lesions might require exenteration.

• Surgical complications depend on technique and are discussed in greater detail in reviews of surgery.
• Chemotherapy complications should be managed by an oncologist.

Disease-related complications

• Recurrence
• Local invasion
• Intracranial invasion (Ueda, Neurol Med Chir (Tokyo). 2003)
• Metastasis

Patient instructions

Follow closely for recurrent orbital signs including decreased vision, pain, proptosis, diplopia or a palpable mass.

1. Bajaj MS, Pushker N, Kashyap S, Sen S, Vengayil S, Chaturvedi A. Fibrous histiocytoma of the lacrimal gland. Ophthal Plast Reconstr Surg. 2007 Mar-Apr;23(2):145-7.
2. Black EH, et al. Smith and Nesi’s Ophthalmic Plastic and Reconstructive Surgery. 3rd ed. New York: Springer; 2012; 848-9.
3. Cole SH, Ferry AP.Fibrous histiocytoma (fibrous xanthoma) of the lacrimal sac. Arch Ophthalmol. 1978 Sep;96(9):1647-9.
4. Tieger MG, Jakobiec FA, Ma L, and Wolkow N. Small benign storiform fibrous tumor (fibrous histiocytomas) of the conjunctival substantia propria in a child: review and clarification of biologic behavior. Ophthalmic Plast Reconstr Surg. 2019; epub ahead of print.
5. Stefanyszyn MA, Hidayat AA, Pe’er JJ, Flanagan JC. Lacrimal sac tumors. Ophthal Plast Reconstr Surg. 1994 Sep;10(3):169-84.
6. Shields JA, Husson M, Shields CL, Krema H, Eagle RC Jr, Singh AD. Orbital malignant fibrous histiocytoma following irradiation for retinoblastoma. Ophthal Plast Reconstr Surg. 2001 Jan;17(1):58-61.
7. Font RL, Hidayat AA. Fibrous histiocytoma of the orbit. A clinicopathologic study of 150 cases. Hum Pathol. 1982 Mar;13(3):199-209.
8. Char D, Caputo G, Miller T. Orbital fibrous histiocytomas. Orbit. 2000 Sep;19(3):155-159.
9. Ueda R1, Hayashi T, Kameyama K, Yoshida K, Kawase T. Orbital malignant fibrous histiocytoma with extension to the base of the skull–case report. Neurol Med Chir (Tokyo). 2003 May;43(5):263-6.
10. Zhang GB, Li J, Zhang PF, Han LJ, Zhang JT. Radiation-induced malignant fibrous histiocytoma of the occipital: a case report. World J Surg Oncol. 2014 Apr 17;12:98
11. AAO, Basic and Clinical Science Course. 2010-11.
12. Garrity JA, Henderson JW. Henderson’s Orbital Tumors. 4th edition. Lippincott Williams & Wilkins. 2007.
13. Rootman J. Diseases of the Orbit: A multidisciplinary approach. 2nd revised edition, Lippincott Williams & Wilkins. 2002.