What’s the difference between a squamous cell carcinoma vs a basal cell carcinoma? Skin cancers can affect your eye. Read more about it here.
Cancer can affect many parts of the body, including the eyeball and eyelid. There are a number of different types of cancerous skin lesions that can be found around the eyes. These include squamous cell carcinoma of the eyelid and eyelid basal cell carcinoma. In ophthalmology, these diseases fall under the subspeciality of an oculoplastic surgeon. Keep reading to find out the differences between squamous cell carcinoma vs basal cell carcinoma of the eyelids.
What is Cancer?
Cancer is an abnormal, uncontrolled growth of cells. This resultant mass, if malignant, can then invade and spread through other tissues in a process called metastasis. Invasion of cancerous cells into the various parts of the body causes damage and inhibits its proper functioning.
A carcinoma is a type of cancer arising from epithelial tissue. These cells are found in the skin but also can line our internal organs, such as the kidneys, and also our body cavities, such as the chest cavity. There are also different types of epithelial cells, which can give rise to different types of carcinoma cancers., including sebaceous carcinoma and squamous cell carcinoma of the eyelid, melanoma, and eyelid basal cell carcinoma.
In addition to cancers of the eyelid, the eyeball itself can also develop malignant lesions. Carcinomas and melanomas can be found on the conjunctiva of the eye, which is the translucent membrane covering the whites (sclera). Cancer can also be found inside the eye, such as retinoblastoma in children or choroidal melanomas in adults.
Squamous Cell Carcinoma vs Basal Cell Carcinoma of the Eyelid
At a basic level, squamous cell carcinoma of the eyelid and eyelid basal cell carcinoma differ based on the type of epithelial cell they arise from. As the names suggest, squamous cell carcinomas grow from squamous cells, which are thin, flat cells commonly found on the surface of the skin. Basal cells are small and round, found in the base (the lower layer) of the outermost layer of the skin, the epidermis.
It’s important for an oculoplastic surgeon to differentiate squamous cell carcinoma vs basal cell carcinoma as the management can be different based on the typical behaviours and characteristics of these two different types of cancers.
Squamous Cell Carcinoma
Eyelid basal cell carcinoma is significantly more common compared to squamous cell carcinomas of the eyelid; some research tells us it can be up to 40 times more common. Around the eyelid area, squamous cell carcinoma accounts for only 5% of cancers.
Squamous cell carcinoma has been associated with a number of different causes, including:
- Older age
- Excessive UV exposure
- Skin damage from chemicals such as cigarette smoke or arsenic exposure
- Burned skin or chronic ulcers
- Viruses, including human papillomavirus (HPV) or human immunodeficiency virus (HIV)
This type of eyelid cancer also appears to be more common in males and in those with lighter complexions. Unsurprisingly, people who live in regions with high UV radiation exposure are also at a higher risk of developing squamous cell carcinoma.
In addition to assessing your history and risk factors. your oculoplastic surgeon will perform a thorough physical examination of the eyelid lesion. He or she will be looking for distinguishing characteristics such as:
- A painless nodular bump with irregular rolled edges
- Chronic scaliness or crustiness of the overlying skin
- Any bleeding
- Distortion of the surrounding eyelid tissues, such as loss of eyelashes
A definitive diagnosis of squamous cell carcinoma is typically only made after a full-thickness biopsy. This helps your oculoplastic surgeon to rule out other possible diagnoses and also determine how far the cancer has spread if it is a carcinoma. Compared to basal cell carcinomas, squamous cell carcinoma has a tendency to invade other tissues (that is, metastasise).
If a squamous cell carcinoma is diagnosed, the usual treatment of choice is complete surgical removal. The oculoplastic surgeon will run a test to ensure the entire tumour has been excised and also surgically repair the eyelid area after the lesion has been removed. If the carcinoma has metastasised, further radical surgery or chemotherapy may be required to ensure all malignant cells have been destroyed. In some cases of superficial squamous cell carcinomas, it may be appropriate to use a topical medication.
Basal Cell Carcinoma
Basal carcinomas of the eyelid account for over 90% of malignant eyelid lesions. Fortunately, they are much less likely to metastasise compared to squamous cell carcinoma.
Similar to squamous carcinomas of the eyelid, basal cell carcinomas are associated with lighter-skinned patients with a history of UV damage to the skin. Other risk factors include:
- Old scarring
- Radiation exposure
It can be difficult to distinguish a basal cell carcinoma from a squamous one; sometimes, the clinical features are very similar. Features of basal cell carcinoma can also include ulceration and bleeding, crusting of the skin, eyelash loss, and distortion of the surrounding eyelid tissues. The characteristic appearance of a basal cell carcinoma is a crater-shaped bump with a central ulcer and rolled edges. However, they can also appear as a thickened plaque of skin with no obvious ulcer and indistinct edges.
Prompt treatment of basal cell carcinoma is important to minimise the risk of metastasis to neighbouring tissues. This can be achieved with complete excision through surgery or a topical cream. However, some research has demonstrated that the cream is less effective compared to surgical excision.
A suspect diagnosis of any type of cancer can be frightening. The prognosis for eyelid cancer goes downhill with larger tumours, lesions that have been around for longer, and tumours that are more deeply or widely invasive. For this reason, any new or changing bump around your eye and eyelid should be assessed by an eye care professional without delay.
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Note: Any surgical or invasive procedure carries risks. Before proceeding, you should seek a second opinion from an appropriately qualified health practitioner.
Types of cancer.
Squamous Carcinoma of the Eyelid. https://eyewiki.aao.org/Squamous_Carcinoma_of_the_Eyelid#:~:text=by%20Preeti%20Thyparampil%2C%20MD%20on%20November%203%2C%202022.&text=Squamous%20Cell%20Carcinoma%20(SCC)%20of,times%20more%20common%20than%20SCC.
Basal Cell Carcinoma.
Management of Eyelid Malignancies.