Squamous cell carcinoma of the eyelid

A skin cancer arising from squamous cells, with the capacity to spread

Squamous cell carcinoma arises from the keratinocytes, the squamous cells that form the majority of the outer layer of the skin. On the eyelid it accounts for around 5% of eyelid skin cancers, making it the second most common after BCC. It is significantly more aggressive, with a genuine capacity to metastasise to regional lymph nodes and, if neglected, to distant sites.

SCC can arise de novo, or it can develop from a precursor lesion called actinic keratosis (also known as a solar keratosis), which is a rough, scaly patch caused by cumulative UV damage. When actinic keratosis is found on the eyelid, it should be treated before progression occurs.

The upper eyelid is more commonly affected by SCC than by BCC, which is unusual when compared with the general pattern of eyelid skin cancers. Both lids and the lid margins can be involved.

What SCC looks like on the eyelid

SCC does not have the same classic pearly, rolled border that makes BCC recognisable. Instead, it typically presents as a scaly, crusted, erythematous (red) plaque or nodule that may bleed on contact. Ulceration is common, and the surface tends to feel rough or irregular to the touch. It can resemble a persistent eczematous patch, a chronic keratosis, or an inflamed lump at the lid margin.

The rate of growth is typically faster than BCC. Patients often notice that the lesion has changed significantly over weeks rather than months, and that it does not settle with simple measures. Eyelash loss in the region of the tumour may be present, as with BCC.

At the lid margin, SCC can be particularly challenging to recognise because it may mimic chronic blepharitis, a persistent stye, or a keratotic plaque associated with blepharitis. This is one of the reasons that a chronic lid margin abnormality that does not respond to treatment should be biopsied rather than repeatedly treated empirically.

SCC can also invade nerves, a phenomenon known as perineural infiltration. When this occurs, patients may notice tingling, numbness, or altered sensation in the skin around the affected area. These symptoms in the context of an eyelid or periorbital lesion should always prompt urgent specialist assessment, as perineural spread is an indicator of more aggressive behaviour and influences how the tumour needs to be managed.

Sun damage, immunosuppression, and pre-existing skin conditions

The risk factors for eyelid SCC broadly mirror those for SCC elsewhere on the skin. Cumulative UV radiation exposure is the most important factor, which is why SCC of the eyelid is most common in older patients with fair skin who have spent significant time outdoors, particularly in high-UV environments.

Immunosuppression substantially increases the risk of SCC and alters its behaviour, making it more aggressive and more likely to metastasise. Patients who have undergone organ transplantation and are on long-term immunosuppressive medication have a greatly elevated lifetime risk of SCC, and eyelid lesions in this group require a particularly low threshold for biopsy and treatment.

Human papillomavirus (HPV) is implicated in some cases of eyelid SCC, particularly those arising at the lid margin. Xeroderma pigmentosum and other DNA repair disorders confer very high lifetime risk of multiple skin cancers including SCC from an early age.

Surgery with margin control, followed by eyelid reconstruction

As with BCC, the primary treatment for eyelid SCC is surgical excision with histological confirmation of clear margins. The excision margins required for SCC are typically wider than those for BCC, reflecting its greater tendency to infiltrate surrounding tissue.

For high-risk lesions (those that are large, deeply invasive, at the inner canthus, or occurring in immunocompromised patients), sentinel lymph node biopsy is sometimes recommended to assess whether microscopic spread to the regional lymph nodes has occurred. This procedure is performed by a head and neck or plastic surgical team and involves injection of a tracer around the tumour, followed by identification and removal of the sentinel (first-draining) lymph node for pathological examination.

Eyelid reconstruction after SCC excision follows the same principles as reconstruction after BCC excision. An oculoplastic surgeon repairs the defect using techniques appropriate to its size and location, with the aim of restoring both eyelid function and appearance.

Adjuvant radiotherapy may be recommended following excision of high-risk tumours, particularly if perineural invasion or lymphovascular invasion is identified on pathology.