Sinonasal Schwannoma – A Case Report

Abstract

A 35-year-old man presented with a history of nasal blockage more on the right side since two years. Other symptoms included rhinorrhoea, headache, recurrent epistaxis, mouth breathing and disturbed sleep since six months.Local examination revealed right and left nostril showing pale polypoid mass, insensitive to touch and it did not bleed on touching. Probe could be passed all around it. CT revealed mildly enhancing soft tissue density lesion arising from right maxillary sinus and extending into right nasal cavity causing its widening with extension anteriorly upto right anterior nares and into ethmoidal air cells and posteriorly into choana resulting into slit like nasopharynx, thereby causing deviation of nasal septum to left side with frontal, sphenoidal and ethemoidal sinusitis. No bone destruction or intracranial extension was seen [Table/ Fig-1]. Excision of nasal mass was done by Weber ferguson approach. After osteotomy, a grayish white mass was seen in the maxillary antrum extending into the nasal cavity. Bone destruction was not seen. The mass was removed completely and sent for histopathological examination. Gross examination showed tissue fragments collectively of size 5x4 cm, gelatinous with circumscribed margins [Table/ Fig-2].Microscopic examination showed cellular areas comprised of spindle shaped cells arranged in short bundles and forming interlacing fascicles with nuclear palisading in verocay bodies. These were Antony A areas. While in some areas the spindle cells were seen irregularly arranged in loose myxoid matrix, these hypocellular areas were Antony B areas [Table/ Fig-3]. There were no mitotic figures or areas of necrosis. It showed positivity for S-100 protein thus confirming the diagnosis [Table /Fig-4]. The above findings were consistent with a diagnosis of sinonasal schwanoma. After surgery there were no postoperative complications, patient was relieved of his symptoms and in one year follow up there was no recurrence. DISCUSSIONSchwannoma also called neurilemmoma is a slow growing benign neoplasm arising from schwann cells in the peripheral nerve sheath. Approximately 45% of schwannomas arise from head and neck region [1]. Less common sites for schwannomas are scalp, face, oral cavity, and respiratory track. Sinonasal schwannomas are very rare, and represent less than 4% of the schwannomas of head and neck region [2][3][4]. The ethmoidal sinus is most commonly involved followed by maxillary sinus, nasal fossa and sphenoidal sinus [4,5]. The involvement of nasal cavity and paranasal sinuses is rare with very few cases reported [6,7]. The most common age group involved is between 0-78 years with no sex or racial predilection [4]. Patient may complain of nasal obstruction, epistaxis, rhinorrhoea, anosmia, facial swelling or pain [8]. Macroscopically schwannomas appear as gelatinous or cystic well encapsulated masses. Microscopically schwannomas are classified into three major histological types [9]. Hypercellular or Antony A areas comprised of spindle shaped cells arranged in interlac...

Right Ethmoidal Sinus Schwannoma: Case Report of a Common Entity with an Unusual Presentation

“…Wong E et al [8] reported a case of sinonasal schwannoma in sixth decade in their case report. Mitra B et al [2] , Vaidya MM et al [3] , Dhawle MS et al [4] and Mangubat EZ et al [6] documented schwannoma in male patient. On the contrary, Singh M et al [5] , Mosalleum EMA [7] and Wong E et al [8] reported the lesion in female patients in their case reports.…”

“…[7] In contrast to other lesion, Schwannoma shows characteristic histopathological features. [4] Neurofibromas are positive for S-100, EMA and NF. Immunoreactivity for EMA in meningioma can be helpful to exclude the diagnosis.…”

“…Vaidya MM et al [3] , Dhawle MS et al [4] , Mangubat EZ et al [6] , Mosalleum EMA [7] et al documented the tumor in fourth decade. Singh M et al [5] observed the lesion in fifth decade.…”

“…Schwannomas are benign slow growing nerve sheath tumors that arise from schwann cells, derived from the neuroectoderm. [4,5] Solitary schwannoma is also called as neurilemmoma, neurolemmoma, perineural fibroblastoma and neurinoma. [2,5] Schwannommas may be encountered at any age.…”

“…Vaidya MM et al [3] also reported a case of Schwanomma arising from right ethmoidal sinus with similar presentation (intracranial extension into anterior cranial fossa). Dhawle MS et al [4] documented the tumor arising from right maxillary sinus. Singh M et al [5] reported the lesion involving the right ethmoidal sinus, maxillary sinus and bilateral sphenoidal sinuses.…”