Solitary Fibrous Tumor: 58 year old man with painless mass in orbit

By Hari Bodhireddy, MSIII
Texas Tech University Health Sciences Center School of Medicine, Lubbock, TX

Chief Complaint: 58 year old male complaining of eyelid swelling, OS.

History of Presenting Illness: Patient states eyelid OS is edematous and erythematous, and he denies pain and diplopia. Symptoms have been present for over one year.

Medical History/Ocular History: History of multiple fractures. No orbital fractures. No previous ocular history.

Social History: Social drinker, non-smoker, employed and works 40 hours/week

Family History: Mother and one brother have hypertension

Medications/Allergies: Herbs and vitamins, no known drug allergies

Review of Systems: Patient denies any additional symptoms (such as nausea/vomiting/dizziness/headache/fever/chills)

Ocular Exam:
Visual Acuity – OD 20/20, OS 20/20, OU 20/20
Pupils – pupils are 3mm OU, with 3+ reactivity OU, and no APD OU
External Eye Exam
Hertel Exophthalmometer –
Lateral separation of exophthalmometer = 96
Forward position of the corneal apex OD = 19
Forward position of the corneal apex OS = 16
Slit Lamp Exam – Ptosis and 3+ edema, OS. There is visualization of a mass in the superior nasal aspect of the left orbit.Remaining portion of the eye exam normal.

Figure 1. Contrast-enhanced axial MRI of orbit. Note the enhancing mass lesion anterior to the left eye.

Figure 2. Contrast-enhanced coronal MRI of orbit. Note the enhancing mass lesion anterior to the left eye.

Figure 3. H&E stain showing concentrated oval to spindle cells (upper left) and interspersed thick collagen bundles (lower right).

Figure 4. A) Immunohistochemical stain for CD34 in tumor cells. B) Immunohistochemical stain for Bcl2 in tumor cells.

Diagnosis: Solitary fibrous tumor (SFT)

Key Facts
· 58 year old male with >1 yr. history of edema and erythema of eyelid OS
· Mass in superior nasal aspect of the left orbit
· Compression and displacement of globe, OS posteriorly
· Cellular spindle cell neoplasm with characteristic immunohistochemical staining

Discussion

Solitary fibrous tumors (SFTs) are rare spindle-cell neoplasms (Figure 3) originating from mesnechymal fibroblast-like cells. They occur in various body sites, but most often in serosal surfaces of the pleura. Other reported sites include the lung, mediastinum, upper respiratory tract, pericardium, soft tissue, peritoneum, and orbit. This variation in location suggests an undifferentiated mesenchymal neoplasm [1].

Orbital SFTs were first described by Dorfman et al. and Westra et al. in 1994. About 50 cases of orbital SFT have been reported in literature to date [2]. SFTs can present at any age, but are most common in the fifth and sixth decades of life. Varied presentations of SFT of the orbit have been documented, including painless swelling of affected eye (Figures 1 and 2) and nasolacrimal duct obstruction [3]. They are generally benign, but local recurrence and metastasis should increase suspicion for a malignant process [2]. Recurrent tumors in the orbit tend to infiltrate surrounding tissues and bone, thus complicating complete secondary excision [4]. The long-term prognosis for extrapleural sites is still uncertain due to the limited number of reported cases. The clinical/radiologic differential diagnosis includes numerous neoplastic and non-neoplastic entities, thus necessitating biopsy. Treatment of choice is complete surgical excision and careful follow-up [4].

Histologic differential diagnosis includes other mesenchymal tumors, such as fibrous histiocytoma (positive for histiocytic marker CD68), hemangiopericytoma, fibrous meningioma (positive for epithelial marker EMA), and leiomyoma (positive for smooth muscle marker actin). It should be noted that this case of SFT involved tumor cells that stained positive for CD34 (Figure 4A), CD99, and Bcl2 (Figure 4B). The tumor cells stained negative for all other mesenchymal markers. Morphologic similarities and underrecognition are reasons for extrapleural SFTs to be confused with the other mesenchymal tumors described [5].

References

1. Havlik DM, Farnath DA, Bocklage T. Solitary fibrous tumor of the orbit with a t(9;22)(q31;p13). Arch Pathol Lab Med. 2000; 124: 756-8.

2. Mukherjee B, Biswas J. Solitary fibrous tumor of the orbit. Indian J Pathol Microbiol 2008; 51: 453-5.

3. Lucas DR et al. Solitary fibrous tumor of the orbit. Int J Surg Pathol 1995; 2(3): 193-8.

4. Bernardini FP, de Conciliis C, Schneider S, Kersten RC, Kulwin DR. Solitary fibrous tumor of the orbit: Is it rare? Report of a case series and review of the literature. Ophthalmology 2003; 110: 1442-8.

5. Warraich I, Dunn DM, Oliver JW. Solitary fibrous tumor of the orbit with epithelioid features. Arch Pathol Lab Med. 2006; 130(7): 1039-41.