The precursor lesion, which is typically a rough, scaly patch on a sun-exposed surface without the induration or nodularity of an invasive SCC.
A non-pigmented malignant melanoma that can be a pink nodule, but is often more rapidly growing and can only be excluded by biopsy.
A painful, shallow ulcer on mucosal surfaces that heals spontaneously, unlike a persistent, indurated oral SCC.
Presents as violaceous or 'plum-colored' nodules that are typically non-ulcerated and firm, without the keratinization seen in SCC.
Characterized by its pearly, translucent appearance and surface telangiectasias, and is much less likely to have a hyperkeratotic crust than SCC.
SCC in situ, which presents as a well-demarcated, scaly, erythematous plaque, but lacks the deep induration or nodularity of invasive SCC.
An exquisitely tender, firm papule with a central crust located on the helix or antihelix of the ear, resulting from pressure-induced inflammation.
Can cause hyperkeratotic plaques, but they are typically atrophic, have follicular plugging, and are located in sun-exposed areas.
A rapidly growing, dome-shaped nodule with a central keratin-filled crater that may spontaneously involute, but is often treated as SCC due to clinical overlap.
An intense, boggy, inflammatory form of tinea capitis, not a firm, indurated tumor, and is associated with hair loss.
A white, adherent patch on a mucous membrane that cannot be scraped off; it is a clinical term for a lesion that requires biopsy to rule out dysplasia or SCC.
A firm, skin-colored or violaceous nodule that appears in a patient with a known history of internal cancer.
A unilateral, eczematous plaque on the nipple or anogenital skin, representing an intraepidermal adenocarcinoma.
A friable, bright red, vascular papule that bleeds easily with minor trauma, unlike the firm, hyperkeratotic nature of most SCCs.
A benign lesion with a greasy, warty, 'stuck-on' appearance that can be scraped off, unlike the firm, indurated SCC.
A verrucous papule that disrupts skin lines and may have thrombosed capillaries (black dots), but lacks the induration of an SCC.
