- Malignant tumour of squamous layer of cells of the epidermis
- Much less common than BCC.
- Greater potential for metastasis
- Affects elderly, fair-skinned individuals
- Usually found on lower eyelid
PATHOGENESIS:
- Exact mechanism not known.
- Environmental and intrinsic stimuli lead to loss of cell growth and regulation
-Most periorbital SCCs arise from actinic lesions, also arise de novo
Environmental factors:
-UV exposure
-Ionizing radiation
-Arsenic ingestion
Psoralen plus UV-A (PUVA) therapy for psoriasis
HPV
Intrinsic factors:
-Skin scarring. (Most common)
-Xeroderma pigmentosum
-Oculocutaneous albinism
-Chronic skin dermatoses
-Skin ulceration
PRESENTATION:
Erythematous, indurated, hyperkeratotic plaque or nodule with irregular margins
-High tendency towards ulceration
-Affect eyelid margin and medial canthus
-Possibility of perineural invasion and lymphatic spread present
DIAGNOSIS:
-Clinical appearance
-Confirmed by histological biopsy
PATHOLOGY:
Well differentiated SCC:
-Exhibits polygonal cells with abundant eosinophilic cytoplasm and hyperchromatic nuclei
-Dyskeratosis, keratin pearls, intercellular bridges and abnormal mitotic figures are prominent
Poorly-differentiated SCC:
-Little keratinization
-Fewer intercellular bridges
TREATMENT:
-Wide local surgical excision - Moh's technique or under frozen section control
-Irradiation
-Cryotherapy
-Orbital exenteration - if invasion of deep orbital tissue is seen
Image from Rajan Eye Care Hospital
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