Angiosarcoma Arising in a Vagal Schwannoma - Report and Literature Review.

Schwannoma and angiosarcoma are rare occurrences. Angiosarcoma's occurrence in a preexisting schwannoma is a very rare event with only fifteen cases reported in the literature. We report the sixteenth case of angiosarcoma arising in a schwannoma, a 30-year-old male patient with a long-standing (15 years) history of right neck lump. The lump measured around 10x7 cm at the time of presentation and all cranial nerves were intact. We performed a fiberoptic laryngoscopy and a computed tomography scan of the head and neck with contrast. Our provisional diagnosis was a parapharyngeal space neoplasm, most likely a salivary gland malignancy. The tumor was excised surgically. On histopathology it contained two distinct tissue architectures representing a schwannoma and epithelioid angiosarcoma, also confirmed on immunohistochemistry. Literature review of these limited cases implicates a poor prognosis of the disease. The pathogenesis is uncertain, but the theories put forward suggest chronic vascular stasis or vascular endothelial proliferation as possible etiologies. The main takeaway of our report is to consider the potential of malignancy in long standing cases of schwannomas. Prompt surgical treatment should be offered, and the patient and their family be counselled for postoperative adjuvant treatment for better prognosis.