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DOI: 10.1055/s-0040-1714224
Rare Presentation of Schwannoma in the Ankle: A Case Report[*]
Article in several languages: português | EnglishAbstract
Schwannomas are benign slow-growing tumors that constitute 8% of all soft-tissue tumors. The clinical signs and symptoms are often misinterpreted because of the low incidence, and these tumors are often misdiagnosed. A 39-year-old male patient presented with non-traumatic solitary swelling in the posteromedial aspect of the right ankle that gradually increased in size and was associated with pain. Clinically, the swelling was firm, non-fluctuant, and was not associated with sensorimotor impairment. Surgical excision of the swelling was performed without damaging the surrounding vessels and nerves. The histopathological examination of the excised tumor revealed a schwannoma.
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Introduction
Schwannomas are benign slow-growing soft-tissue tumors that arise from Schwann cells of the peripheral nerve sheaths. They constitute 8% of all soft-tissue tumors.[1] Of all the reported cases, between 12% and 19% are located in the upper extremity, and between 10% to 13%, in the lower extremity. Its common locations are the flexor surface of the extremities, the neck, the mediastinum, the retroperitoneum, the posterior spinal roots, and the cerebellopontine angle.[2] The clinical signs and symptoms are often misinterpreted because of the low incidence, and schwannomas are often misdiagnosed as other soft-tissue tumors, such as neurofibroma.
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Case Presentation
A 39-year-old male patient presented to the outpatient department with complaints of a non-traumatic solitary swelling over the posteromedial aspect of the right ankle associated with mild pain. He had noticed the swelling 15 years before, and it gradually increased in size and was associated with pain that was mild to moderate in intensity and intermittent in nature. There was no significant family history.
The clinical findings showed firm swelling over the posteromedial aspect of the ankle measuring 3 × 2 × 2 cm approximately, and it was non-fluctuant, non-pedunculated, non-compressive, and with no transillumination present. There was no sensorimotor impairment in the right leg and foot.
A magnetic resonance imaging (MRI) scan of the leg ([Fig. 1a,b,c]) revealed a well-circumscribed lesion in the subcutaneous plane in the posteromedial aspect of the distal third of the leg abutting underlying soleus and tAchilles tendon with no definitive evidence of infiltration likely benign lesion? neurogenic.
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We proceeded with the surgical excision of the swelling after we obtained consent and the complications were explained. The skin overlying the swelling was incised in a curved fashion, and a dissection was performed to demarcate the capsule of the tumor that was incised. Further fine blunt dissection was performed circumferentially along the branch of the posterior tibial nerve, with the perineural sheath attached. The tumor was retracted and removed without damaging the surrounding vessels and nerves ([Fig. 2a,b]).
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The nerve was fully preserved and examined before closure. The excised tumor was sent for a histological study ([Fig. 2c]). The postoperative period was uneventful, with good skin healing and well-preserved nerves.
The histopathological examination revealed a Schwannoma ([Fig. 3]) consisting of Antoni type A tissue, which is composed of highly cellular spindle-shaped cells surrounding the Verocay bodies and Antoni type B tissue, which consists Schwann cells.
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Discussion
Schwanommas in the lower extremities are limited to less than 10% of all cases, according to a study by Albert et al.[3] Our case is rare, as the literature search results show very few case reports of schwannomas affecting the posterior tibial nerve.
Delay in the diagnosis is often peculiar in cases of tibial-nerve schwanomma; our patient was operated after 15 years of the onset of symptoms. A similar delay in diagnosis, of up to 10 years, was reported by Ghaly.[4] Smith and Amis[5] reported pain in the foot for 8 years before the recognition of a schwannoma, while Nawabi and Sinisi[6] suggested that the mean time to diagnose the schwannoma was of 86.5 months (more than 7 years).
Extracapsular excision is a commonly-used technique[7] that may be associated with the risk of developing postoperative neurological deficits. During tumor dissection, to reduce the risk of damage to the nerve fascicles, Hussain et al.[8] proposed tumor release by incising the capsule far laterally to the path of the nerve and dissecting circumferentially, with the epineural capsule behind to act as a protective covering; in our case, we incised the capsule in the dorsal aspect, as we knew that the nerve was in the ventral aspect. This was followed by dissection until the nerve and further fine dissection separating it from the parent nerve.
The present is a report of a rare location of a schwannoma of the posterior tibial nerve in the posteromedial aspect of the ankle, which was managed by excision, with no neurovascular damage.
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Conflito de Interesses
Os autores declaram não haver conflito de interesses.
* Work developed at Department of Sports Medicine, Sir Ganga Ram Hospital, Sarhadi Gandhi Marg, Old Rajinder Nagar, New Delhi, India.
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Referências
- 1 Adani R, Baccarani A, Guidi E, Tarallo L. Schwannomas of the upper extremity: diagnosis and treatment. Chir Organi Mov 2008; 92 (02) 85-88
- 2 Fletcher CD. Peripheral nerve sheath tumors. A clinicopathologic update. Pathol Annu 1990; 25 (Pt 1): 53-74
- 3 Albert P, Patel J, Badawy K. et al. Peripheral Nerve Schwannoma: A Review of Varying Clinical Presentations and Imaging Findings. J Foot Ankle Surg 2017; 56 (03) 632-637
- 4 Ghaly RF. Um neurilemoma do nervo tibial posterior não reconhecido por 10 anos: relato de caso. Neurocirurgia 2001; 48 (03) 668-672
- 5 Smith W, Amis JA. Neurilemoma of the tibial nerve. A case report. J Bone Joint Surg Am 1992; 74 (03) 443-444
- 6 Nawabi DH, Sinisi M. Schwannoma of the posterior tibial nerve: the problem of delay in diagnosis. The Journal of bone and joint surgery 2007; 89-B (06) 814-816
- 7 Rockwell GM, Thoma A, Salama S. Schwannoma of the hand and wrist. Plast Reconstr Surg 2003; 111 (03) 1227-1232
- 8 Hussain M, Jhattu H, Pandya A. et al. A precise excision technique for schwanommas. Eur J Plast Surg 2012; 36 (02) 111-114
Endereço para correspondência
Publication History
Received: 29 February 2020
Accepted: 15 April 2020
Article published online:
22 September 2020
© 2020. Sociedade Brasileira de Ortopedia e Traumatologia. This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes, or adapted, remixed, transformed or built upon. (https://creativecommons.org/licenses/by-nc-nd/4.0/)
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Referências
- 1 Adani R, Baccarani A, Guidi E, Tarallo L. Schwannomas of the upper extremity: diagnosis and treatment. Chir Organi Mov 2008; 92 (02) 85-88
- 2 Fletcher CD. Peripheral nerve sheath tumors. A clinicopathologic update. Pathol Annu 1990; 25 (Pt 1): 53-74
- 3 Albert P, Patel J, Badawy K. et al. Peripheral Nerve Schwannoma: A Review of Varying Clinical Presentations and Imaging Findings. J Foot Ankle Surg 2017; 56 (03) 632-637
- 4 Ghaly RF. Um neurilemoma do nervo tibial posterior não reconhecido por 10 anos: relato de caso. Neurocirurgia 2001; 48 (03) 668-672
- 5 Smith W, Amis JA. Neurilemoma of the tibial nerve. A case report. J Bone Joint Surg Am 1992; 74 (03) 443-444
- 6 Nawabi DH, Sinisi M. Schwannoma of the posterior tibial nerve: the problem of delay in diagnosis. The Journal of bone and joint surgery 2007; 89-B (06) 814-816
- 7 Rockwell GM, Thoma A, Salama S. Schwannoma of the hand and wrist. Plast Reconstr Surg 2003; 111 (03) 1227-1232
- 8 Hussain M, Jhattu H, Pandya A. et al. A precise excision technique for schwanommas. Eur J Plast Surg 2012; 36 (02) 111-114
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