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Epibulbar schwannoma: a case report and review of the literature

      Schwannoma or neurilemmomas are benign tumours of neural origin. They arise from the Schwann cells present in the peripheral myelinated nerves. The head and neck region is the most common site of occurrence for schwannomas, followed by flexor aspects of limbs and trunk.
      • Das Gupta T.K.
      • Brassfield R.D.
      • Strong E.W.
      • Hajdu S.I.
      Benign solitary Schwannomas (neurilemomas).
      Ophthalmic schwannomas most commonly occur in the orbital region and account for 1% of all orbital tumours.
      • Shields J.A.
      • Shields C.L.
      • Scartozzi R.
      Survey of 1264 patients with orbital tumors and simulating lesions: The 2002 Montgomery Lecture, part 1.
      Other rare ophthalmic sites include choroids, eye lids, sclera, and conjunctiva.
      • Le Marc’hadour F.
      • Romanet J.P.
      • Fdili A.
      • Peoc’h M.
      • Pinel N.
      Schwannoma of the bulbar conjunctiva.
      Conjunctival or epibulbar schwannoma is an extremely rare entity with only 11 cases reported in the English literature to date.
      • Nair A.G.
      • Kaliki S.
      • Mishra D.K.
      • Dave T.V.
      • Naik M.N.
      Epibulbar schwannoma in a 12-year-old boy: a case report and review of literature.
      There was no case of conjunctival schwannoma in an extensive review of 1643 conjunctival tumours by Shields et al.
      • Shields C.L.
      • Demirci H.
      • Karatza E.
      • Shields J.A.
      Clinical survey of 1643 melanocytic and nonmelanocytic conjunctival tumors.
      We describe an extremely rare case of a epibulbar nodular mass that was histopathologically confirmed as schwannoma in a 17-year-old Indian male patient.
      The patient presented to our oculoplasty clinic with history of mass in the left inferior conjunctival region for the previous 2 years. The mass was painless and gradually increasing in size. There was no history of frequent redness, watering, itching, or any bleeding episodes. Systemic history was unremarkable.
      On examination, his best-corrected visual acuity was 20/20 OU. Slit-lamp examination of the left eye revealed a well-circumscribed oval mass located at the 5 o’clock position over the inferotemporal bulbar conjunctiva (Fig. 1A). The mass was firm, nontender, freely mobile, and not adherent to the underlying sclera. The rest of the ophthalmic examination in both eyes was unremarkable. There was no lymphadenopathy.
      Fig. 1
      Fig. 1A, External photograph showing a well-circumscribed oval pinkish mass over the bulbar conjunctiva in the inferotemporal quadrant. B, Microphotograph (hematoxylin and eosin, 20×) showing a well-capsulated tumour composed of spindle cells intermixed with tiny blood vessels. Numerous Verocay bodies are seen (arrow head). Inset showing 4× magnification of the tumour and encircled zone showing Verocay bodies. C, Immunohistochemistry showing tumour cells to be positive for S-100 antigen.
      Based on the findings a differential diagnosis of conjunctival inclusion cyst, conjunctival granuloma, allergic reactive lymphoid hyperplasia, or a parasitic cyst was considered. The patient underwent complete excision of the mass. Peroperatively the mass was found to be located subconjuctivally without any underlying scleral adhesions and was easily removed in toto. Conjunctiva was approximated with the help of electrocautery.
      Histopathologic examination revealed a well-encapsulated tumour composed of spindle cells intermixed with tiny blood vessels. Numerous Verocay bodies could be seen. There was no nuclear atypia. The findings were consistent with schwannoma (Fig. 1B). Immunohistochemistry was strongly positive for S-100, confirming the diagnosis of schwannoma (Fig. 1C).
      The patient did not report for a follow-up after surgery and hence was contacted over phone after 6 months. There was no recurrence.
      Conjunctival schwannoma is an extremely rare entity. No case of conjunctival schwannoma was found in a review of 1643 conjunctival tumours by Shields et al.,
      • Shields C.L.
      • Demirci H.
      • Karatza E.
      • Shields J.A.
      Clinical survey of 1643 melanocytic and nonmelanocytic conjunctival tumors.
      whereas only a single case of conjunctival schwannoma was reported in a review of 2455 conjunctival tumours by Grossniklaus et al.
      • Grossniklaus H.E.
      • Green W.R.
      • Luckenbach M.
      • Chan C.C.
      Conjunctival lesions in adults. A clinical and histopathologic review.
      In a review, 6 out of 7 cases of conjunctival schwannomas were found to be epibulbar; hence, epibulbar schwannoma was proposed as a more descriptive term for these cases.
      • Demirci H.
      • Shields C.L.
      • Eagle Jr, R.C.
      • Shields J.A.
      Epibulbar schwannoma in a 17-year-old boy and review of the literature.
      Of the 11 reported cases of conjunctival schwannoma to date,
      • Le Marc’hadour F.
      • Romanet J.P.
      • Fdili A.
      • Peoc’h M.
      • Pinel N.
      Schwannoma of the bulbar conjunctiva.
      • Nair A.G.
      • Kaliki S.
      • Mishra D.K.
      • Dave T.V.
      • Naik M.N.
      Epibulbar schwannoma in a 12-year-old boy: a case report and review of literature.
      • Grossniklaus H.E.
      • Green W.R.
      • Luckenbach M.
      • Chan C.C.
      Conjunctival lesions in adults. A clinical and histopathologic review.
      • Demirci H.
      • Shields C.L.
      • Eagle Jr, R.C.
      • Shields J.A.
      Epibulbar schwannoma in a 17-year-old boy and review of the literature.
      • Dabezies Jr, O.H.
      • Penner R.
      Neurofibroma or neurilemmomoma of the bulbar conjunctiva.
      • Vincent N.J.
      • Cleasby G.W.
      Schwannoma of the bulbar conjunctiva.
      • Charles N.C.
      • Fox D.M.
      • Avendaño J.A.
      • Marroquín L.S.
      • Appleman W.
      Conjunctival neurilemoma. Report of 3 cases.
      • Andreoli C.M.
      • Hatton M.
      • Semple J.P.
      • et al.
      Perilimbal conjunctival schwannoma.
      • Ohshima K.
      • Kitada M.
      • Yamadori I.
      Neurilemoma of the bulbar conjunctiva.
      the single case reported by Grossniklaus et al.
      • Grossniklaus H.E.
      • Green W.R.
      • Luckenbach M.
      • Chan C.C.
      Conjunctival lesions in adults. A clinical and histopathologic review.
      did not have any clinical details. The rest of the reported cases did not show any sex predilection with 6 being female and 4 male. Patient age ranged from 10 to 72 years. Seven cases had bulbar involvement, 2 were palpebral, and 1 case involved the fornix. Our case also involved the bulbar conjunctiva. Except for 2 cases,
      • Dabezies Jr, O.H.
      • Penner R.
      Neurofibroma or neurilemmomoma of the bulbar conjunctiva.
      • Vincent N.J.
      • Cleasby G.W.
      Schwannoma of the bulbar conjunctiva.
      all cases were proven by immunohistochemistry. Charles et al.
      • Charles N.C.
      • Fox D.M.
      • Avendaño J.A.
      • Marroquín L.S.
      • Appleman W.
      Conjunctival neurilemoma. Report of 3 cases.
      reported a series of 3 cases of conjunctival schwannoma in 1997. Interestingly, all the cases in the series were females. Five out of total 12 reported cases (41.66%; including the present case) were below 20 years of age, signifying a predilection for adolescent age group. The details of all the cases reported to date have been summarized in Table 1.
      Table 1Table depicting the details of all reported cases of conjunctival schwannomas to date
      AuthorsYearAge (years)/SexEyeLocation and Clinical FeaturesManagementIHCRecurrence
      Dabezies and Penner
      • Dabezies Jr, O.H.
      • Penner R.
      Neurofibroma or neurilemmomoma of the bulbar conjunctiva.
      196150/FOSSubconjunctival superotemporal bulbar noduleExcisionNAYes
      Vincent and Cleasby
      • Vincent N.J.
      • Cleasby G.W.
      Schwannoma of the bulbar conjunctiva.
      196812/FODBulbar mass lateral to caruncleExcisionNANo
      Grossniklaus et al.
      • Grossniklaus H.E.
      • Green W.R.
      • Luckenbach M.
      • Chan C.C.
      Conjunctival lesions in adults. A clinical and histopathologic review.
      198761/FNANAExcisionNANo
      Le Marc’hadour et al.
      • Le Marc’hadour F.
      • Romanet J.P.
      • Fdili A.
      • Peoc’h M.
      • Pinel N.
      Schwannoma of the bulbar conjunctiva.
      199637/MOSSubconjunctival lobulated massExcisionS-100+No
      HMB-45
      -VE
      Charles et al.
      • Charles N.C.
      • Fox D.M.
      • Avendaño J.A.
      • Marroquín L.S.
      • Appleman W.
      Conjunctival neurilemoma. Report of 3 cases.
      199719/FOSInferior fornicial bilobed massExcisionS-100+No
      Charles et al.
      • Charles N.C.
      • Fox D.M.
      • Avendaño J.A.
      • Marroquín L.S.
      • Appleman W.
      Conjunctival neurilemoma. Report of 3 cases.
      199726/FOSSubconjunctival superior limbal massExcisionS-100+No
      Charles et al.
      • Charles N.C.
      • Fox D.M.
      • Avendaño J.A.
      • Marroquín L.S.
      • Appleman W.
      Conjunctival neurilemoma. Report of 3 cases.
      199772/FODPedunculated tarsal massExcisionS-100+No
      Andreoli et al.
      • Andreoli C.M.
      • Hatton M.
      • Semple J.P.
      • et al.
      Perilimbal conjunctival schwannoma.
      200468/MOSNasal perilimbal massExcisionS-100+ HMB-45No
      -VE
      Ohshima et al.
      • Ohshima K.
      • Kitada M.
      • Yamadori I.
      Neurilemoma of the bulbar conjunctiva.
      200710/FOSTemporal palpebral massExcisionS-100+ SMA -VENo
      Demirci et al.
      • Demirci H.
      • Shields C.L.
      • Eagle Jr, R.C.
      • Shields J.A.
      Epibulbar schwannoma in a 17-year-old boy and review of the literature.
      201017/MOSSuperonasal bulbar mass, adherent to scleraExcision + cryotherapyS-100+, CD-34/CD-68/SMANo
      -VE
      Nair et al.
      • Nair A.G.
      • Kaliki S.
      • Mishra D.K.
      • Dave T.V.
      • Naik M.N.
      Epibulbar schwannoma in a 12-year-old boy: a case report and review of literature.
      201512/MOSInferotemporal bulbar mass adherent to scleraExcisionS-100+No
      Alam et al. (present study)201617/MOSInferotemporal bulbar mobile massExcision + cauteryS-100+No
      It has been proposed that these conjunctival schwannomas might arise from either the nasociliary nerves supplying the conjunctiva or the subconjuctivally lying autonomic nerve fibres.
      • Ohshima K.
      • Kitada M.
      • Yamadori I.
      Neurilemoma of the bulbar conjunctiva.
      Histopathological features of conjunctival schwannomas are no different from schwannomas affecting the rest of the body. Two distinct patterns (i.e., Antony A and Antony B) are seen. The former is more cellular and consists of tightly packed spindle cells with spindle-shaped nuclei forming Verocay bodies, whereas the latter has sparse cells and more of myxoid stroma.
      • Demirci H.
      • Shields C.L.
      • Eagle Jr, R.C.
      • Shields J.A.
      Epibulbar schwannoma in a 17-year-old boy and review of the literature.
      Immunohistochemically, they are positive for the neural crest marker S-100.
      Complete excision is the treatment of choice for conjunctival schwannoma. A double freeze–thaw cryo can be applied to the underlying sclera bed if the mass is found to be adherent to underlying sclera peroperatively.
      • Nair A.G.
      • Kaliki S.
      • Mishra D.K.
      • Dave T.V.
      • Naik M.N.
      Epibulbar schwannoma in a 12-year-old boy: a case report and review of literature.
      • Demirci H.
      • Shields C.L.
      • Eagle Jr, R.C.
      • Shields J.A.
      Epibulbar schwannoma in a 17-year-old boy and review of the literature.
      To conclude, conjunctival schwannomas are rare tumours with very few cases described in the literature. They should be considered in the differential diagnosis of any subconjunctival nodular mass. Complete excision offers cure in most of the patients without any recurrence.

      References

        • Das Gupta T.K.
        • Brassfield R.D.
        • Strong E.W.
        • Hajdu S.I.
        Benign solitary Schwannomas (neurilemomas).
        Cancer. 1969; 24: 355-366
        • Shields J.A.
        • Shields C.L.
        • Scartozzi R.
        Survey of 1264 patients with orbital tumors and simulating lesions: The 2002 Montgomery Lecture, part 1.
        Ophthalmology. 2004; 111: 997-1008
        • Le Marc’hadour F.
        • Romanet J.P.
        • Fdili A.
        • Peoc’h M.
        • Pinel N.
        Schwannoma of the bulbar conjunctiva.
        Arch Ophthalmol. 1996; 114: 1258-1260
        • Nair A.G.
        • Kaliki S.
        • Mishra D.K.
        • Dave T.V.
        • Naik M.N.
        Epibulbar schwannoma in a 12-year-old boy: a case report and review of literature.
        Indian J Ophthalmol. 2015; 63: 620-622
        • Shields C.L.
        • Demirci H.
        • Karatza E.
        • Shields J.A.
        Clinical survey of 1643 melanocytic and nonmelanocytic conjunctival tumors.
        Ophthalmology. 2004; 111: 1747-1754
        • Grossniklaus H.E.
        • Green W.R.
        • Luckenbach M.
        • Chan C.C.
        Conjunctival lesions in adults. A clinical and histopathologic review.
        Cornea. 1987; 6: 78-116
        • Demirci H.
        • Shields C.L.
        • Eagle Jr, R.C.
        • Shields J.A.
        Epibulbar schwannoma in a 17-year-old boy and review of the literature.
        Ophthal Plast Reconstr Surg. 2010; 26: 48-50
        • Dabezies Jr, O.H.
        • Penner R.
        Neurofibroma or neurilemmomoma of the bulbar conjunctiva.
        Arch Ophthalmol. 1961; 66: 73-75
        • Vincent N.J.
        • Cleasby G.W.
        Schwannoma of the bulbar conjunctiva.
        Arch Ophthalmol. 1968; 80: 641
        • Charles N.C.
        • Fox D.M.
        • Avendaño J.A.
        • Marroquín L.S.
        • Appleman W.
        Conjunctival neurilemoma. Report of 3 cases.
        Arch Ophthalmol. 1997; 115: 547-549
        • Andreoli C.M.
        • Hatton M.
        • Semple J.P.
        • et al.
        Perilimbal conjunctival schwannoma.
        Arch Ophthalmol. 2004; 122: 388-389
        • Ohshima K.
        • Kitada M.
        • Yamadori I.
        Neurilemoma of the bulbar conjunctiva.
        Jpn J Ophthalmol. 2007; 51: 68-69