Orbital Solitary Fibrous Tumor in a Commercial Airline Pilot
BACKGROUND: In the literature, central serous retinopathy (CSR) accompanying solitary fibrous tumors (SFT) in a pilot has not been reported. In airline pilots, mass effect-related symptoms such as diplopia, ptosis, etc., seen with orbital tumors may endanger flight safety. CASE REPORT: A 62-yr-old male commercial airline pilot presented with blurred vision in the right eye. He had been receiving treatment for 2 mo because of CSR. His visual acuity was 10/20 in the right eye and 20/20 in the left. During examination, ptosis and exophthalmos were noticed in the right eye. Ocular movements were free in all cardinal directions and there was downward displacement in the right eye. There was no diplopia. Magnetic resonance imaging revealed a 1.5- to 2-cm well-defined contrast-enhancing mass in the lateral extraconal orbit. His medical flight certificate was suspended for 3 mo due to decreased visual acuity and superior visual defect. Superior orbitotomy was performed without any complication. Ptosis and CSR had regressed 1 wk after surgery. All systemic and ophthalmological examinations met aviation medical certificate requirements. He returned to flight on the condition of being checked every 3 mo. At the 1-yr follow-up, there was no sign of recurrences of SFT or CSR. DISCUSSION: SFTs are slow-growing neoplasms that can manifest symptoms related to mass effect. In the current literature, there are no reported cases of the coexistence of orbital SFT and CSR or pilots able to resume flight duties only 1 wk after a successful orbitotomy and tumor resection surgery. Altinbas M, Ozpınar A, Akbaba M, Nacaroglu SA, Sargolzaeimoghaddam M, Sargolzaeimoghaddam M. Orbital solitary fibrous tumor in a commercial airline pilot. Aerosp Med Hum Perform. 2024; 95(6):333–336.
Solitary fibrous tumors (SFT) are infrequent spindle-cell neoplasms derived from mesenchymal tissue, with occurrences in various anatomical locations such as the pleura, mediastinum, pericardium, kidney, liver, and lung. Additionally, there have been rare cases where SFTs originate from the head and neck region.1,3 In 1994, Dorfman et al. and Westra et al., respectively, provided the first description of SFT in an orbit.4,13 SFT typically progresses benignly; however, there are rare occurrences of malignancy with invasion and local recurrences.1 Orbital SFT typically results in painless proptosis within 2 yr and has a peak incidence in the fifth and sixth decades of life, but it can happen to people of all ages, from 9 to 76.4 The cure is accomplished through complete removal of the tumor.11 Stereotactic radiosurgery is recommended as an additional form of treatment when complete removal of the tumor is not feasible.11
CASE REPORT
In August 2022, a 62-yr-old male commercial airline pilot presented to our clinic with blurred vision in his right eye. He had been receiving treatment in another clinic for 2 mo due to central serous retinopathy. According to our ophthalmic examinations, his best corrected visual acuity was 20/40 in the right eye and 20/20 in the left eye. Central macular thickness was 371 μm in the right eye and 217 μm in the left eye and macular pigment epithelium was irregular in the left eye. The patient was diagnosed with central serous retinopathy (CSR). His medical flight certificate was suspended for 3 mo due to not meeting visual acuity requirements in accordance with Turkish civil aviation regulation. During examination, edema was noticed in his right superior eyelid. When questioned, he had been aware of this edema for the last 2 yr and asked if we could do ptosis surgery to fix his right eyelid while he was away from flying. There was painless ptosis and exophthalmos in the right eye, but no palpable mass on the right upper eyelid. His Hertel measurements were 21 mm for the right eye and 17 mm for the left eye with a downward displacement in the right eye (Fig. 1). Ocular movements were free in all cardinal directions and there was a superior visual field defect in his right eye. His anterior segment examination was within normal limits bilaterally. Intraocular pressure was measured as 19 mmHg (right) and 20 mmHg (left). There was no diplopia.
Citation: Aerospace Medicine and Human Performance 95, 6; 10.3357/AMHP.6385.2024
Orbital contrast MRI was performed and MRI revealed the presence of a 1.5–2 cm (about 0.79 in) well-defined contrast-enhancing mass in the superior lateral extraconal orbit (Fig. 2). There were no abnormalities of either brain lobes, meninges, or remaining structures.
Citation: Aerospace Medicine and Human Performance 95, 6; 10.3357/AMHP.6385.2024
Diazomid and topical nonsteroid anti-inflammatory were started for CSR. Superior orbitotomy was performed on the right eye. The tumor was completely resected through an upper lid crease incision without any complication. The removed tissue sample was sent for culture and pathological evaluation. The result of pathological evaluation was a 2.8 cm (about 11.02 in) × 2.1 cm (about 8.27 in) × 2 cm (about 0.79 in) encapsulated spindle cell neoplasm (Fig. 3).
Citation: Aerospace Medicine and Human Performance 95, 6; 10.3357/AMHP.6385.2024
The mitotic count was 1 per 10 high-power fields and the tumor displayed moderate cellularity, slight pleomorphism, hyalinized stroma, and myxoid alterations. Necrosis was not present. Tumor cells were shown by immunohistochemistry to be highly positive for CD34, STAT-6, and BCL-2. A negative result was obtained for SOX-10, S-100, MDM-2, epithelial membrane antigen, MUC4, and CD99. The appearance and immunohistochemical characteristics led to the diagnosis of a single fibrous tumor. The tumor had a score of 2 based on its age, size, necrosis, and mitotic activity, and its danger level was low. The macula’s subretinal fluid had decreased 1 wk after surgery and the right eye’s corrected visual acuity had reached 20/20. Stereopsis was measured as a 50-s arc and visual fields were normal in both eyes. Ocular movements were free in all directions and there was no sign of diplopia. Ptosis and exophthalmos had regressed (Fig. 4). All systemic and ophthalmological examinations were found to meet aviation medical certificate requirements and were stable 3 mo after the patient’s flying privileges were withdrawn, so his medical certificate was approved with the restriction of requiring an ophthalmological examination every 3 mo and he returned to flying again. In his 1-yr follow-up, there was no sign of recurrence of SFT in the contrast MRI and optical coherence tomography did not show any CSR activation. Systemic and visual findings were suitable for flying safety.
Citation: Aerospace Medicine and Human Performance 95, 6; 10.3357/AMHP.6385.2024
DISCUSSION
SFT is a rare fusocellular tumor that was previously only reported in the pleura and lung until 1990. However, it has since been observed in various anatomical locations, including the extremities, respiratory tract, thyroid gland, sublingual gland, breast, periosteum, brain, and orbit.1,3 SFT typically occurs in individuals in their sixth decade of life, similar to our patient, who is 62 yr of age. Extrapleural SFTs tend to manifest at a younger age compared to pleural SFTs, with a mean age of 50.3 yr.10 At this time, there is no established risk factor for the emergence of SFTs.8
SFTs are typically asymptomatic and slow-growing neoplasms that are frequently diagnosed incidentally.3,7,8 However, they can manifest symptoms related to the mass effect they exert.1,3,11 In our case, the patient presented with progressive upper eyelid edema persisting for 2 yr. Orbital fibrous solitary tumors typically present as painless proptosis that progressively worsens, primarily affecting middle-aged individuals.1 These tumors are predominantly found in the superior and medial regions of the orbit, although there have been rare instances reported in the conjunctiva or lacrimal sac.1,7 Visual disturbances, papilledema, restricted ocular movements, diplopia, strabismus, exophthalmos, and ptosis may also result from these tumors. While infrequent, literature has reported cases where patients experienced pain, entrapment, and nerve palsies associated with SFTs. Optic nerve compression caused by SFTs is not commonly observed according to existing literature.7,8 On the other hand, cases of optic disc pallor, optic disc edema, and choroidal effusion have also been reported in cases of orbital SFT, documented as contributing factors to decreased visual acuity. Postoperative resolution of optic disc abnormalities highlights the importance of tumor resection in alleviating optic nerve compression and associated visual complications. There was no optic disc abnormality or choroidal fold in this case; however, the presence of CSR resolved markedly and rapidly after tumor resection. The coexistence of SFT and CSR, which has not been previously reported, suggests that orbital tumor compression may have triggered the development of CSR, but further investigation of such a unique relationship is warranted.6 In some occupational groups, such as airline pilots, symptoms such as diplopia, visual field-limiting ptosis, and globe movement limitation that may be seen with orbital SFT may prevent people from continuing to do their jobs. In our case, there was no diplopia or restriction of globe movement, but ptosis caused a defect in the visual field. This prevented our patient from practicing his pilot profession for 3 mo because he had difficulty seeing the top panel in the cockpit and could not meet the visual acuity requirements due to CSR.
Even though SFT and other orbital lesions like cavernous hemangioma, schwannoma, localized neurofibroma, varix, and orbital metastasis are difficult to distinguish with CT and MRI, the pattern of contrast enhancement and washout on dynamic imaging may be able to help.8 According to the literature, bone remodeling is typically observed in instances with suspected malignant transformation and recurrence.7 In the instances we examined using radiological imaging, we did not observe bone remodeling. A well-defined, firm, vascular tumor with a consistent internal structure and low to medium reflectivity is what SFT appears to be.5,7,10 But definitive diagnosis for SFTs is made with molecular markers.
Prior to the discovery of molecular markers for tumors, SFT and hemangiopericytoma were considered to be different forms of the same tumor. In the present World Health Organization Classification of Soft Tissue and Bone Tumors, SFT is now recognized as a fibroblastic neoplasm with moderate aggressiveness.5,8,10 The uncommon differentiated form of SFT has the potential to develop into either low- or high-grade sarcoma and, in some cases, may exhibit features of osteosarcoma or rhabdomyosarcoma in primary or recurring tumors. Additionally, instances of neuroendocrine and squamous differentiation as well as frequent local recurrence have been documented.5,10
Histological characteristics of SFTs resemble those of mesenchymal tumors, including a variety of soft tissue sarcomas. Furthermore, certain types of SFTs, such as fat-forming SFTs that typically affect deep soft tissues, have been documented to occur in the orbit. The majority of giant-cell variants of SFTs commonly manifest in the periorbital soft orbit.5,8,10
Hemangiopericytoma, fibrous histiocytoma, optic nerve sheath meningioma, neurofibroma, and schwannoma should be considered in the differential diagnosis.5 Variable morphology can be distinguished with advanced immunohistochemical methods. CD34 (90–100%) positivity is commonly observed in many cases.2,6 Vimentin, CD99, and BCL-2 expressions are sensitive and occur in most cases, but these markers have low specificity. Epithelial membrane antigen, cytokeratin, keratin, S100, smooth muscle actin, and Desmin negativity is seen in most cases. STAT-6 is an important marker that has high sensitivity and specificity and is also seen in malignant cases. Smooth muscle tumors, leiomyoma, etc., show strong positivity for Desmin, SOX10, and negativity for S100, CD34, and BCL2. Dedifferentiated liposarcoma shows MDM2 positivity in most cases. Neural tumors such as schwannoma show strong positivity for S100. Also, the NAB2-signal transducer and activator of STAT6 gene inversion were determined with an antibody described as sensitive and specific for SFT. Our case has CD34, STAT6, and BCL2 positivity and CD99, S100, SOX10, MDM2 negativity.5,10
The recommended approach for treating SFT is to perform a complete resection, if feasible.7–9 Close monitoring is particularly crucial for identifying any recurrences or metastasis.9 In our case, the patient’s tumor was suitable for complete resection. Complications like mass effect because of bleeding, etc., due to orbitotomy were not seen. Despite undergoing a complete resection, there have been documented instances in the literature where SFT has been found in the same or different locations.8,9,12 Thompson et al. showed that although the mitotic index is the only factor used in all models, there are significant benefits in considering tumor size, patient age, cellular composition, pleomorphism, and tumor necrosis. These factors have traditionally played a role in assessing the likelihood of malignancy or recurrence. Therefore, it is imperative to conduct a comprehensive evaluation and regularly follow up with patients using a multidisciplinary approach. In the current literature, there are no reported cases of orbital SFT and CSR coexistence in a pilot who was able to resume flight duties only 1 wk after a successful orbitotomy and tumor resection surgery.
Ptosis and exophthalmos in the right eye.
Superior lateral extraconal well-defined contrast-enhanced mass.
2.8 × 2.1 × 2 cm encapsulated solitary fibrous tumor.
One week after surgery.
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