Schwannomas are benign, slow-growing nerve tumours that develop from schwann cells. Schwann cells play an important role in the propagation of nerve impulses by encapsulating the nerve fibres of peripheral nerves, cranial nerves and nerves of the autonomic system [1]. Head and neck schwannomas account for 25-45% of all schwannomas and are dominated by vestibular schwannomas. Clinically, cutaneous schwannomas are generally asymptomatic, presenting as a slowly growing mass causing cosmetic damage; neurological signs such as pain or paresthesia may be found in one third of cases.Histologically, schwannomas are characterised by a proliferation of elongated spindle cells, with elongated nuclei often arranged in a palisade pattern called Antoni A type (Verocay corps), while those in which the cells are loose and irregularly arranged are called Antoni B type [2]. Immunohistochemical study often shows positive staining for S-100 protein [3]. The treatment of choice is surgical removal. Dissection of this type of tumour is facilitated by the presence of a capsule which forms a smooth surface under the skin. Local recurrence has rarely been reported.

A 30-year-old patient with no notable pathological history who has had a rounded (Fig. 1a), pearly white asymptomatic nodule above the upper lip for about 3 months (Fig. 1b). The patient consulted for major cosmetic damage. An excisional biopsy was performed showing a histological and immunohistochemical appearance in favour of a cutaneous schwannoma. Annual surveillance was recommended.

Figure 1: (a) Regular rounded nodule above the upper lip. (b) Pearly white dermoscopic appearance.

REFERENCES

1. Benchafai I, Fetouhi A, Allaoui M, Ouraini S, Jahidi A, Benariba F:Schwannoma of the ear lobe:an etiology that should be taken into consideration in patients. Case report. Pan Frican Med J. 2020;2:1.

2. Cotran RS, Kumar V. Robbins and Cotran Pathologic Basis of Disease. 7^th ed. Philadelphia:Saunders Elsevier;2005. Peripheral nerve sheath tumors;pp. 1411–3.

3. Tzu-Chun L, Po-Yuan W, Tze-Yi L, Tsong-Liang L. An infrequent plexiform variant of schwannoma of the glans penis:a rare finding. Asian J Androl. 2010;12:455–7.