|Year : 2020 | Volume
| Issue : 2 | Page : 115-118
A rare case of alveolar soft-part sarcoma of orbit
Viji Rangarajan, Sindhuja Murugesan, Kavitha Ramakrishnan, S Priya
Department of Orbit and Oculoplasty, Aravind Eye Hospital, Coimbatore, Tamil Nadu, India
|Date of Submission||24-Nov-2019|
|Date of Decision||06-Jan-2020|
|Date of Acceptance||03-Apr-2020|
|Date of Web Publication||17-Jun-2020|
Dr. Viji Rangarajan
No. 41, 4th Street, Lakshmi Nagar, Vadavalli Road, Edayarpalayam, Coimbatore - 641 025, Tamil Nadu
Source of Support: None, Conflict of Interest: None
Alveolar soft-part sarcoma (ASPS) is a very rare, highly vascular, soft-tissue sarcoma predominantly seen in adolescents and young adults. Orbital involvement is rare, and only few case reports have been published. We report the case of a 12-year-old girl who presented with proptosis of the right eye of 2 months' duration. Magnetic resonance imaging showed a well-defined lesion in the superolateral right orbit, with the possibility of a hemangioma. Right-eye lateral orbitotomy with excision biopsy of the mass was done. Histopathology revealed ASPS, and the patient was referred for metastatic workup.
Keywords: Alveolar soft-part sarcoma, orbit, pediatric
|How to cite this article:|
Rangarajan V, Murugesan S, Ramakrishnan K, Priya S. A rare case of alveolar soft-part sarcoma of orbit. TNOA J Ophthalmic Sci Res 2020;58:115-8
|How to cite this URL:|
Rangarajan V, Murugesan S, Ramakrishnan K, Priya S. A rare case of alveolar soft-part sarcoma of orbit. TNOA J Ophthalmic Sci Res [serial online] 2020 [cited 2021 Aug 5];58:115-8. Available from: https://www.tnoajosr.com/text.asp?2020/58/2/115/286925
| Introduction|| |
Alveolar soft-part sarcoma (ASPS) is an extremely rare sarcoma, which constitutes about 0.5%–1% of all soft-tissue sarcomas. It has an indolent course and generally has a poor prognosis. ASPS was first defined and named by Christophersonet al. in 1952. It is more commonly seen in young adults ranging between 15 and 35 years, with a 3:1 female preponderance. The disease usually presents as a painless mass in the lower limbs, head, or neck. Treatment is mainly surgical, with chemotherapy and radiotherapy being adjuvants. Involvement of the orbit is rare, with only few case reports published in literature.
| Case Report|| |
A 12-year-old girl presented to us with complaints of protrusion of her right eye for duration of 2 months. There was no history of diplopia or defective vision. She denied any past neurological or ophthalmological problems. Her best-corrected visual acuity (BCVA) in both eyes was 6/6. Right-eye anterior segment examination revealed axial proptosis, and there was no palpable mass [Figure 1]. Posterior segment examination revealed a hyperemic edematous disc with blurred margins and choroidal folds. Left-eye anterior segment and fundus examination was normal [Figure 2]. There was mild restriction of abduction in the right eye. Ultrasonography of the right eye showed a well-defined lesion involving the temporal intraconal space between the optic nerve and lateral rectus muscle, abutting the optic nerve. Moderate irregular internal reflectivity with mild attenuation was noted [Figure 3]. Magnetic resonance imaging (MRI) orbit showed well-defined, 26 mm × 23 mm × 20 mm, enhancing lesion in the superolateral aspect of the extraconal and intraconal space of the right orbit causing mild proptosis suggestive of hemangioma [Figure 4]. The lesion was seen indenting on the globe, abutting the optic nerve, and the lateral rectus muscle was displaced superiorly by the lesion. Right-eye lateral orbitotomy was done, and the mass was removed in toto. Macroscopic examination showed an oblong-shaped, whitish, smooth, firm mass of about 30 mm × 20 mm in dimension [Figure 5]. Histopathological examination revealed alveolar nests and aggregates of oval-to-polygonal cells with vesicular nuclei [Figure 6]. Abundant clear-to-eosinophilic cytoplasm and sparse mitotic figures were noted [Figure 7]. It had periodic acid–Schiff (PAS)-positive diastase-resistant granules [Figure 8]. PAS is an important stain for the diagnosis of ASPS, as it shows PAS-positive diastase-resistant granules in more than 80% of cases. Immunohistochemistry was negative for neural and epithelial markers. Postoperatively, there was no proptosis, and her extraocular movement was full and BCVA was 6/6 [Figure 9]. Both her fundus examination was normal [Figure 10]. She was referred to an oncologist for metastatic workup, which did not show evidence of disease elsewhere in the body. Postoperative MRI after 3 and 6 months showed no residual macroscopic disease in the orbit, and computed tomography chest showed no evidence of lung metastasis.
|Figure 2: Preoperative fundus. The right eye shows disc hyperemia with choroidal folds. Left-eye fundus is normal|
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|Figure 3: Ultrasound orbit – Well-defined lesion involving the temporal intraconal space between the optic nerve and lateral rectus muscle|
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|Figure 4: Magnetic resonance imaging orbit – Well-defined enhancing extraconal and intraconal lesion in the superolateral aspect of the right orbit|
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|Figure 6: Histopathology: (a) Encapsulated mass with tumor nests separated by fibrovascular septa|
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|Figure 7: Large polyhedral cells with eosinophilic granular cytoplasm with prominent nucleoli arranged in alveolar pattern|
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|Figure 8: Immunohistochemistry – periodic acid–Schiff-positive intracytoplasmic crystalline structure|
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| Discussion|| |
ASPS is a rare soft-tissue sarcoma with 0.5%–1% incidence. The exact histogenesis of ASPS is still unknown. Studies have shown that ASPS exhibits an abnormality in the form of an unbalanced translocation der(17)t(X;17)(p11;q25), which fuses the N-terminal region of the alveolar soft-part locus gene, located at 17q25, to the C-terminal region of the transcription factor E3 (TFE3), located at Xp11.
In adults, it predominantly affects the deep soft tissues of the extremities, particularly the thighs and buttocks. In children, it is most commonly seen in the head-and-neck region, particularly the orbit and tongue. The most common presenting feature is painless, nonpulsatile, and nonreducible proptosis with no extraocular movement restriction.
Radiologically, ASPS may appear to have iso- to hyperintensity on T1-weighted imaging (WI) and hyperintensity on T2-WI because of abundant, but slow, blood flow within the tumor. Histopathologically, round-to-polygonal cells with abundant cytoplasm showing crystalline structures which are PAS positive and diastase resistant are seen. The tumor cells show organoid arrangement or uniform nests separated by delicate fibrous septae or network of reticulin fibers, giving an alveolar appearance.
The clinical differential diagnosis of ASPS is schwannoma, neurofibroma, or hemangioma because of its high vascularity, circumscribed nature of the lesion, orbital location, and closeness to the rectus muscle or optic nerve. Pathologically, the differential diagnosis includes malignant melanoma, paraganglioma, alveolar rhabdomyosarcoma, and granular cell tumor. More than 80% of the cases of ASPS possess PAS-positive, diastase-resistant, needle-shaped crystals. The majority of ASPS tumor cells exhibit moderate-to-strong nuclear staining of TFE3, which is a sensitive and specific marker for ASPS. On immunohistochemistry, ASPS is usually negative for epithelial markers such as epithelial membrane antigen and CK, but CD34 and CD31 are positive, which shows the vascular nature of the lesion.
Treatment involves complete surgical removal of the tumor with postoperative adjuvant radiotherapy to control the rate of recurrence. Chemotherapy has no role in ASPS treatment. The tumor can metastasize late in the course of the disease (median 6 years), with 38% of metastases appearing 10 years after the diagnosis. Metastasis usually occurs in the lung, brain, or skeletal bone. In general, nonorbital ASPS tends to have poorer prognosis than those with tumors in the orbit. Tumors that occur in younger patients seem to have a better outcome. Poor prognostic factors include increasing age, tumors >5 cm, metastatic disease at initial presentation, and nonorbital ASPS.
| Conclusion|| |
ASPS is an uncommon soft-tissue tumor, which rarely involves the orbit.
Understanding its characteristic microscopic and ultrastructural features would facilitate in early diagnosis. Prompt diagnosis with microscopic and immunohistochemistry helps in early diagnosis and better treatment. Surgery remains the primary modality followed by adjuvant therapy in the form of radiotherapy. Orbital ASPS usually affects younger population; the course of disease is shorter and the tumor size is smaller. Therefore, the prognosis is improved in orbital ASPS.
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.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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