An “Ancient” Schwannoma of Cervical Region

Schwannoma is a benign encapsulated neoplasm which grows slowly. It ori-ginates from Schwann cells, the sheath cells that cover the myelinated nerve fibers. Head and Neck regions account for around 25% - 40% of the cases. Ancient schwannoma is a rare variant wherein degenerative change occurred in a long-standing schwannoma. This causes sudden increase in size and pain, mimicking a malignant change. It was first described by Ackerman and Taylor in 1951. In this article, I would like to present a case of Ancient variant of Cervical Schwannoma.

Int. J. Otolaryngology and Head & Neck Surgery nuclei, and Antony B, characterized by a hypocellular arrangement and a large quantity of myxoid tissue [6]. However, the ancient variant is characterized by degenerative changes typified by perivascular hyalinization, calcification, cystic necrosis, relative loss of Antoni type A tissue, and degenerative nuclei that may be misinterpreted as sarcomatous pleomorphisms. However, the absence of mitosis and the presence of cystic necrosis and a well-defined capsule without surrounding invasion help to differentiate these lesions from high-grade lesions.
Contrast Enhanced CT (CECT) Scan and MRI [7] [8] usually delineate the lesion well. Surgical excision of the mass with preservation of the parent nerve is the treatment of choice.
We present a case of Left Cervical Schwannoma which was diagnosed as the ancient variant upon histological examination.

Case Report
A 36-year-old male presented to us with complaints of painless mass over left side of neck, which was slow growing but had rapidly increased in size over past few weeks. There were no associated complaints like persistent cough or hoarseness of voice. His medical history was unremarkable. On clinical examination, a mass was found in the right level 2 cervical region; deep to the SCM

Discussion
A schwannoma is a benign nerve sheath tumor composed of schwann cells, which normally produce the insulating myelin sheath covering the peripheral nerves [9]. Schwannomas are equally seen in both genders in their third and fourth decades of life [10]. It is mostly asymptomatic, encapsulated, lobulated with smooth margin and remains peripherally attached to at least one nerve N. R. Venkata, M. A. Dodhia  root. Schwannoma of vagus is more commonly reported on the left side compared to the right, as seen in the present case [11] [12]. Most schwannomas are fairly homogeneous soft tissue masses and appear hypodense or isodense to skeletal muscle on non-contrast CT and tend to be hypointense or isointense to skeletal muscle on T1-weighted MR images and variably hyperintense on T2-weighted images. Despite their hypovascularity, they enhance significantly on both CT and MR images and can mimic a paraganglioma. The enhancement of the schwannomas is seen at least 2 minutes after the contrast injection and depicts the equilibrium phase of the contrast agent and the poor venous drainage of the tumor. Dynamic scans can reveal the true nature of the lesion and differentiate it from hypervascular lesions. The enhancement pattern of neural tumors can vary; it may be an inhomogeneous enhancement (owing to necrosis and hemorrhage) or even lack of enhancement [9]. Ancient schwannoma, a degenerative neurilemmoma, a rare variant of schwannoma first described by Int. J. Otolaryngology and Head & Neck Surgery degeneration and diffuse hypocellular areas. These changes are believed to occur because it takes a long time for schwannomas to develop [14]. The radiologic findings for ancient schwannoma are similar to those for schwannoma, which on contrast-enhanced computed tomography shows enhancement in capsules or pericystic areas [7]. It is characterized by degenerative changes typified by perivascular hyalinization, calcification, cysticnecrosis, relative loss of Antoni type A tissue, and degenerative nuclei that may be misinterpreted as sarcomatous pleomorphisms. However, the absence of mitosis and the presence of cystic necrosis and a well-defined capsule without surrounding invasion help to differentiate these lesions from high-grade lesions [7] [8]. Ancient schwannomas are benign tumors and the goal of treatment is complete excision with possible preservation of the involved nerve as complete resection is usually curative with a good prognosis [15].