|Year : 2015 | Volume
| Issue : 4 | Page : 486-489
Cranial and extracranial presentations of schwannoma: Original study
Department of Pathology, Prathima Institute of Medical Sciences, Karimnagar, Andhra Pradesh, India
|Date of Web Publication||14-Jul-2015|
Department of Pathology, Prathima Institute of Medical Sciences, Karimnagar, Andhra Pradesh
Source of Support: None, Conflict of Interest: None
Introduction: Schwannoma is a benign tumor that originates from the Schwann cells of the peripheral nerves. Schwannomas are usually a solitary, slow growing benign neoplasm, and well-encapsulated. The present study was carried out to know the cranial and extracranial presentations of schwannoma at various locations in the body. Materials and Methods: This was a retrospective and prospective study carried out for a period of 2 years, on patients who underwent excision of the tumor at different locations, which were diagnosed as schwannoma on microscopy. Cases were analyzed in detail regarding clinical history and other findings. Results: A total of 28 cases were diagnosed as schwannoma, among them 20 cases were located at cerebellopontine angle. Male:female ratio was 1:1.8. Youngest age group was 28 and eldest was 70 years in our study and the most common age group affected was between 30 and 40 years. Conclusion: Schwannoma should be considered as one of the differential diagnosis for swelling over the body as schwannoma can present extracranially also. Classical schwannoma was the most common and plexiform schwannoma was the least common variant in our study.
Keywords: Cranial, extracranial locations, schwannoma
|How to cite this article:|
Shastry S. Cranial and extracranial presentations of schwannoma: Original study. Med J DY Patil Univ 2015;8:486-9
| Introduction|| |
Schwannoma is a benign tumor that originates from the Schwann cells of the peripheral nerves. Schwannomas are usually a solitary, slow growing benign neoplasm and well encapsulated soft tissue or intrabony lesions deriving from neural crest cells. ,, Schwannomas can arise from any cranial, peripheral, or autonomic nerves that contain Schwann cells, the sheath cells that cover myelinated nerve fibers.  Schwannoma was first reported by Verocay in 1910, called this benign neurogenic tumor as neurinoma. This tumor is often associated with the nerve sheath and adjacent to the parental nerve but extrinsic to the nerve fascicles. The present study was done to know the cranial and extracranial locations of schwannoma.
| Materials and Methods|| |
A retrospective and prospective study was done for a period of 2 years. Male:female ratio was 1:1.8. Fine-needle aspiration cytology (FNAC) was done on few swellings, which were located extracranially and diagnosed as spindle cell lesion. We received only on gross which were diagnosed as schwannoma with cranial location.
| Results|| |
Totally 28 cases were diagnosed as schwannoma and its variants. Among the 28 cases 20 cases were located at cerebellopontine angle, which is the most common location in our study. Other most common location was on forearm contributing 3 cases [Table 1]. Age group between 30 and 40 years affected more in our study contributing 16 cases [Table 2]. Age group between 70 years was the eldest and 28 years was the youngest in our study. Classical schwannoma contributed highest number of cases contributing 23 cases and plexiform schwannoma contributed 1 case [Table 3]. Of the 28 cases, 18 cases were female and 10 cases male.
| Discussion|| |
The schwannoma is also called as neurilemmoma, neurinoma, perineural fibroblastoma and is a solitary, slow growing, usually encapsulated, generally asymptomatic neural tumor. , It can present at any age, however it is more common between the second and third decade of life. The tumor is derived from the Schwann cell sheath, which enlarges, expands and causes displacement and compression of the nerve of origin.
Schwannomas are said to occur more frequently in the 25-55 years age group with 1.6-1 female to male prediliction, but can occur at any age. Although said to occur more frequently in women than in men, there is no definite gender predilection. Clinically, these benign tumors are easily mistaken for other entities such as lipoma and pleomorphic adenoma on account of their slow growth and absence of neural symptoms, and also to mucous retention cyst, minor salivary gland tumor, palatal abscess, fibroma/papilloma, and lymphoma.
The extracranial schwannoma occurs in the head and neck region. The oral schwannomas usually present in the soft tissue, more commonly the tongue, followed by palate, buccal mucosa and may have similar clinical features to other benign lesions such as mucocele, fibromas, lipomas and benign salivary gland tumors. In our study, we reported one case of schwannoma located in right submandibular region extending into oral cavity [Figure 1]. Clinically, it was diagnosed as salivary gland neoplasm or lymphoma. FNAC was done and we diagnosed it as Spindle cell neoplasm. Surgery was done and we received multiple capsulated grey white soft tissue masses with focal yellowish areas, largest one of size 6 cm × 4 cm, firm, cut section showed grey white and pearly white areas [Figure 2].
|Figure 1: Swelling in the right submandibular region (a), swelling extending into oral cavity (b)|
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|Figure 2: Gross showing multiple globular capsulated soft tissue masses (a). Cut section showing grey white areas (b)|
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Moreover, it was confirmed as schwannona on microscopy having both Antoni A and B patterns along with Verocay bodies [Figure 3].
|Figure 3: Section showing spindle to elongated cells arranged in whorls with Antoni A and Antoni B pattern along with Verocay bodies (H and E, ×40)|
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Ancient neurilemmoma exhibits benign degenerative changes in a classic neurilemmoma occurring over time. These changes include cystic, myxoid, edematous and fibrotic areas, vascular abnormalities and atypical cells with pleomorphic nuclei [Figure 4]. Ancient neurilemmoma behaves much like a benign neural neoplasm. We reported two cases of ancient schwannomas in our study.
|Figure 4: Section showing spindle to oval shaped cells with marked nuclear hyperchromatism and atypia — ancient schwannoma (H and E, ×40)|
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Cellular schwannoma is classified based on microscopic examination. However, support for a microscopic diagnosis of cellular schwannoma can be obtained by immunostaining. It differs from classic schwannoma by its increased cellularity, nuclear pleomorphism and hyperchromatism, lack of Verocay bodies, and frequently higher mitotic activity [Figure 5]. In our study we reported two cases.
|Figure 5: Section showing spindle to elongated cells arranged only in hypercellular areas — cellular schwannoma (a) H and E, ×10, (b) H and E, ×40|
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Plexiform schwannomas may present on any location and on microscopy they show tumor cells arranged in whorling pattern in large bundle like [Figure 6].
An immunohistochemical examination of the tumor may show positive results with S100 antigen. Local excision is the treatment of choice. The nonencapsulated form requires a margin of normal tissue and careful separation from the involved nerve is also necessary to preserve normal function. , Recurrence is rare.  Malignant transformation of a benign schwannoma is rare. We compared our study with study done by Jerzvklifanienko and the observation was same in both studies [Table 4].
|Figure 6: Section showing spindle to elongated cells arranged in bundles and in clusters plexiform schwannoma (H and E, ×10)|
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| Conclusion|| |
Classical schwannoma was the most common and plexiform schwannoma was the least common variant in our study. Females are more affected and the most common age group was 30-40 years. Schwannoma should be suspected as one of the differential diagnosis in swellings over the body as it can extracranially also. We present this study to highlight the various locations in the body where schwannoma can occur.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6]
[Table 1], [Table 2], [Table 3], [Table 4]