|Year : 2023 | Volume
| Issue : 2 | Page : 521-523
Malignant peripheral nerve sheath tumor: Rare tumor, rarer presentation
Department of Orbit and Oculoplasty, RJN-Apollo Spectra, Gwalior, Madhya Pradesh, India
|Date of Submission||02-Oct-2022|
|Date of Acceptance||17-Dec-2022|
|Date of Web Publication||28-Apr-2023|
Chandrabhawan, No. 1, Jhansi Road, Behind Baal Bhawan, Gwalior - 474002, Madhya Pradesh
Source of Support: None, Conflict of Interest: None
A 57-year-old male presented with a fleshy mass encroaching on the limbus in the right eye. With a clinical diagnosis of invasive squamous neoplasia, topical interferon-alpha was started. Since the patient had unremitting pain, exenteration was done. Histopathology revealed conjunctival spindle cell neoplasia, and immunohistochemistry markers favored malignant peripheral nerve sheath tumor (MPNST). To the best of our knowledge, this is the first description of orbital MPNST presenting as a surface malignancy.
Keywords: Case report, exenteration, malignant peripheral nerve sheath tumor, neurofibromatosis 1, orbit, radiotherapy
|How to cite this article:|
Likhari K. Malignant peripheral nerve sheath tumor: Rare tumor, rarer presentation. Indian J Ophthalmol Case Rep 2023;3:521-3
Malignant peripheral nerve sheath tumor (MPNST) is a rare sarcoma usually seen in the upper and lower limbs; its occurrence in the orbit is very rare., Previous reports of this tumor in the orbit are of a large deep mass usually in the superior part. We report a patient with a surface malignancy resembling ocular surface squamous neoplasia (OSSN). The histopathologic examination and immunohistochemistry (IHC) markers revealed it to be MPNST. To the best of our knowledge, this is the first report of orbital MPNST presenting as a surface lesion.
| Case Report|| |
A 57-year-old otherwise healthy man presented with a slightly elevated fleshy mass on the right temporal limbus (6 o'clock–9 o'clock) of 6 months' duration with significant congestion and pain radiating to the right forehead [Figure 1]a. There was no proptosis, and motility was normal. The left anterior segment was normal. Best-corrected visual acuity was 20/30 OU, and fundi showed a cup–disk ratio of 0.8 with healthy neuroretinal rims. With a provisional diagnosis of conjunctival-limbal-corneal OSSN, topical interferon-α1 MIU/cc (Million International Units/cc) four times daily was started and the patient was advised about the need for surgery. Although the standard treatment for OSSN is wide excision with cryotherapy to the margins, topical pharmacotherapy has been found to be as effective and well tolerable as surgical excision., Six weeks later, after initial mild relief, the mass seemed to have increased in size and pain was unremitting [Figure 1]b. Magnetic resonance imaging (MRI) showed a 14 × 21 × 11 mm soft tissue lesion (hyperintense on T1, hypointense on T2, enhancing on contrast) predominantly involving the right anterior–inferior conjunctiva with invasion of anterior sclera, inferior rectus, and inferior oblique muscles, showing postcontrast enhancement [Figure 1]c. Enzyme-linked immunosorbent assay (ELISA) for viral markers was negative. A lid-sparing anterior exenteration was done. Histopathologic examination (HPE) showed conjunctival spindle cell neoplasm with surgical margins free of invasion, and IHC markers were positive for S-100, SOX-10 (SRY-box Transcription Factor 10), EMA (Epithelial Membrane Antigen) and TLE-1 (Transducin-like Enhancer of Split-1) favoring malignant peripheral nerve sheath tumor (MPNST) [Figure 1]d and [Figure 1]e. Positron emission tomography (PET) scan done for secondary lesions elsewhere (also, given the rarity of the tumor in the orbit, to rule out a missed primary lesion) was negative. Healing was satisfactory and the patient was referred for radiotherapy [Figure 1]f.
|Figure 1: (a) The right eye at presentation with a firm, congested mass from 6 o'clock to nearly 9 o'clock position, encroaching the limbus. (b) Six weeks later, obvious increase in size and vascularity of the mass was seen. (c) MRI showing the mass (arrow). (d) Exenterated specimen. The mass was removed separately from the eyeball. (e) A picture of the histopathology slides with low magnification above and high magnification below. (f) The socket healing well 4 weeks after lid-sparing exenteration. MRI = magnetic resonance imaging|
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| Discussion|| |
MPNST (previously malignant schwannoma, malignant neurilemmoma, neurogenic sarcoma, and neurofibrosarcoma) is the preferred term for tumors originating from peripheral nerves or their sheaths., Defined as nerve sheath tumors arising from a peripheral nerve, from a preexisting peripheral nerve sheath tumor, or in association with neurofibromatosis type I (NF1), these are rare sarcomas (approximately 4%–10% of all soft-tissue sarcomas) of ectomesenchymal origin, which usually arise in the peripheral nerves of upper or lower extremities, commonest being the sciatic nerve.,, Though they commonly occur in adults of both sexes aged 20–50 years, patients with NF1 are affected earlier (10%–20% affect children, the youngest reported being 4 days old).,, Occurrence in the orbit is very rare, accounting for 0–0.2% of orbital tumors; less than 40 cases have been reported worldwide, almost all of them being large deep orbital masses usually arising from the supraorbital branch of the trigeminal nerve (five presented with a lid lesion or history of a previously excised lid lesion)., However, our patient had a mass on the anterior ocular surface, resembling an invasive OSSN. To the best of our knowledge, this is the first report of an MPNST presenting as an anterior orbital lesion. This malignancy follows a highly aggressive course of recurrence, metastasis, and death; 50%–70% are seen in association with NF1,,,, with the prevalence of MPNST in NF-1 patients being 5%–42% compared to 0.001% in the general population.,, It is the leading cause of death in NF1 patients, with a lifetime incidence of 15.8%. In the previous 34 reports of MPNST, seven (20.6%) patients had NF1 and an equal number had a preexisting lesion (five in orbit/adnexa, two elsewhere), 12 had recurrence (36%), and 14 died (42%). Our patient did not have NF1 or a preexisting lesion.
MPNSTs are fusiform to globular in shape and vary from white and firm to yellow and soft, depending on the absence or presence of necrosis. Orbital MPNSTs usually present as large deep superior orbital masses, with the greatest dimension of the primary tumor reportedly greater than 5 cm in 61% of cases., HPE is essential for diagnosis and shows a highly cellular, spindle-cell neoplasm resembling soft-tissue sarcoma, but with differentiation toward elements of the nerve sheath, Schwann cell, and perineural cell. Frequent mitoses and focal necrosis are typical, but cytologic features can vary and may include fibroblastic, Schwannian, epithelioid, clear cell, or frankly anaplastic–pleomorphic cells., Rarely, heterologous mesenchymal or epithelial elements are present. Although the tumors usually appear well circumscribed, they are not truly encapsulated., Recognizable nerve roots may be seen entering or exiting the tumors, which are often microscopically observed to invade soft tissue and nerve fascicles. MPNSTs have a local recurrence rate between 16% and 52% and demonstrate metastasis in 39% cases (most commonly to the lung);,, the mortality rate is 68%., The most important adverse prognostic features are the presence of NF1, tumor size >5 cm, inadequate resection, >20 mitoses/HPF, histological grades II and III, and regional or distant metastases.,,,
The treatment of choice is surgery, but postoperative radiotherapy and chemotherapy are part of adjunctive therapy, with sporadic MPNST cases responding better to chemotherapy than those associated with NF1., Radiotherapy is recommended for high-grade lesions with positive surgical margins.,,, Despite complete tumor resection with free surgical margins, we advised radiotherapy for the patient, keeping in mind the high recurrence and mortality rate associated with this lesion.
| Conclusion|| |
Thirty-four cases of orbital MPNST have been reported to date, almost all of which were posterior orbital masses. The purpose of this report is to highlight a hereto unreported presentation of a rare malignancy and to review its course and preferred treatment. This would be of special significance as a differential diagnosis in deep/atypical OSSN not responding to topical treatment and in patients presenting with orbital masses who have had MPNST elsewhere in the body. A high index of suspicion is advisable, and work-up should include imaging (MRI) of the tumor and at least a computed tomography (CT) chest for pulmonary metastases. 18-Fluorodeoxyglucose positron emission tomography (FDG-PET) may help in differentiation of benign and malignant tumors, but the final diagnosis is by histopathology. Total resection is the most important therapeutic goal, but when radical tumor removal is not possible, excision combined with high-dose radiation therapy is the best alternative.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
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Conflicts of interest
There are no conflicts of interest.
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