Schwannoma of the Lesser Occipital Nerve: A Rare Case Presentation

Aims: To present an atypical case of a neck swelling in the left posterior triangle.

Case Presentation: A 21 year old girl presented with a painless swelling in left upper neck since 2 months, difficulty in swallowing, fever and loss of appetite since 15 days. On inspection, the swelling could not be seen with the naked eye. On palpation, it was spherical, soft in consistency, non-tender, 2×3 cm in size, deep seated and freely mobile in all directions. The initial differential diagnoses included reactive lymphadenitis or tuberculosis. Ultrasonography revealed left infra-auricular area swelling extending to posterior triangle. Ultrasound guided FNAC suggested lymphocytic granulation tissue and thus, excisional biopsy was done. The mass was pale white in color, globular, without attachments and could be dissected all over. The Histopathological report revealed a Benign Schwannoma.

Discussion: Schwannomas are benign tumors that exhibit Schwann cell differentiation and arise from peripheral nerves. They usually present in the 3rd to the 5th decade. Schwannomas in the neck are a rare occurrence and constitute only 0.5% of all head and neck tumors. In this case, the swelling was quickly progressive in nature which meant that Schwannoma was not among the first few differential diagnoses. The fever and acute presentation gave an impression of an infective or inflammatory lesion with a likelihood of tuberculosis. On dissection, the mass appeared to be encasing a small nerve and plenty of branches were identified which further made the diagnosis totally dependent on HPE.

Conclusion: Schwannomas arising from the lesser occipital nerve have rarely been seen. The atypical nature of this case with respect to the age at presentation, progression of swelling and non-linear symptoms and signs ratio makes it unique.