Pharyngeal schwannomas, pathologically, can be divided into schwannomas and neurofibromas, both of which are relatively rare, but their clinical manifestations and treatments are similar.

bubble_chart Pathological Changes

Pharyngeal nerve sheath membrane tumors are neoplasms that originate from peripheral cranial nerves, sympathetic nerves, and their branches, commonly occurring in the posterior and lateral walls of the pharynx. Histologically, nerve sheath membrane tumors can be classified into neurofibromas and schwannomas (Schwannomas). Neurofibromas are primarily composed of Schwann cells, but their intercellular matrix consists of collagen fibers and mucoid components. These tumors are distinctly encapsulated by a membrane, making it difficult to identify their originating nerve. They are firm in texture, with a pale gray cut surface. Microscopically, the tumor cells appear spindle-shaped and twisted, often arranged in fine bundles, with abundant collagen fibers, hyaline degeneration, and mucoid matrix between the cells, showing a mucopolysaccharide staining reaction. Nerve sheath membrane tumors originate from Schwann cells of nerve fibers and are encapsulated by a membrane composed of the nerve's outer sheath. The originating nerve may attach to the outside or beneath the membrane but does not penetrate the tumor. The tumor can be soft or firm, sometimes with a fluctuant feel, and appears yellowish-brown or grayish-red with visible hemorrhagic spots. Microscopic examination reveals cells arranged in a palisade pattern with alternating nucleated and non-nucleated cells, densely packed, or loosely arranged in a reticular pattern with a watery matrix.

This disease grows slowly and may be asymptomatic when small, discovered incidentally, or accompanied by a foreign body sensation and obvious discomfort. Subsequently, swallowing difficulties and voice changes may occur. Larger tumors can cause breathing difficulties, and compression of nerves may lead to pain. If located in the nasopharynx, hearing loss may occur.

Physical examination may reveal a rounded protrusion on the posterior or lateral pharyngeal wall, with a mucous membrane on the surface. Larger tumors may cause bulging of the soft palate or extend beyond the midline of the pharynx, displacing the palatine arch and tonsils. Palpation may reveal a firm mass, sometimes aligned with the course of cranial nerves, accompanied by signs of nerve involvement.

bubble_chart Diagnosis

Based on the history of slow tumor growth and clinical manifestations, the possibility of a schwannoma should be considered, and the diagnosis can be confirmed by postoperative pathology. It is important to differentiate it from neurofibroma, benign mixed tumors, teratomas, and malignant tumors.

bubble_chart Treatment Measures

Surgical resection is the primary treatment method. Smaller tumors can be removed through the pharynx, while larger tumors may require a cervical approach or a combined pharyngeal and cervical approach for removal.