Cutaneous Squamous Cell Carcinoma (images and
carcinoma is the second most common form of skin cancer. It is usually
noted on sun damaged skin in elderly patients.
Actinic Keratosis ;
Epidermal Tumours .
factors may be intrinsic, extrinsic or both.
The extrinsic factors are ultraviolet sunlight exposure , chemicals
(arsenic, polycyclic aromatic hydrocarbons and those found in tobacco
product), Human papilloma virus (HPV-16 is present in squamous cell
carcinoma of genital and periungual areas). The intrinsic factors include
skin pigmentation, primary dermatoses and hereditary conditions like
xeroderma pigmentosa and oculocutaneous albinism.
There is an increased incidence of squamous cell carcinoma in
immunosuppressed patients . These tumours seem to behave more
aggressively when present in organ transplant recipients and
SUBTYPES OF SQUAMOUS CELL CARCINOMA:
SQUAMOUS CELL CARCINOMA:
nests of atypical squamous cell which arise from the epidermis and extends
into the dermis.The atypical squamous cells are large with pleomorphic
nuclei. Intercellular bridges are present. Numerous atypical mitotic
figures are noted. There are large amounts of keratin with keratin pearl
formation depending on the differentiation of the tumour. There is
evidence of individual cell keratinization.
Presence of invasion of is essential for the diagnosis.
Immunohistochemistry reveals positivity with EMA and cytokeratin. Vimentin
may be positive in poorly differentiated tumour.
Evidence of perineural lymphocytes is suggestive of perineural invasion in
CELL /PLEOMORPHIC/SARCOMATOID VARIANT:
variant usually presents as an exophytic mass on sun exposed skin, in
elderly patients. Microscopically, there are whorls and fascicles of
atypical squamous cells intermingled with collagen fibres. Pleomorphic
giant cells may be present. The spindle cells display elongated
pleomorphic, vesicular nuclei and eosinophilic cytoplasm. Numerous mitotic
figures are present. Presence of dyskeratotic cells and evidence of
continuity with the epidermis assist in the diagnosis of squamous cell
Differential diagnosis include
Immunohistochemistry reveals that the tumour stains postively with EMA ,
cytokeratin and vimentin. These lesions are negative with S100 and other
Clinically, the lesion usually presents as an ulcer or crusted nodule on
the head and neck region. Microscopically, the tumour cells are arranged
in nests and cords and there are clefts produced by acantholysis of cells.
These spaces resemble glandular structures. Dysplastic cells may be
present within the spaces.
This variant often arises from acantholytic solar keratosis.
These are slow growing large warty tumours usually noted at sites of
There are three clinical variants- oral , plantar and anogenital.
Microscopicaly verrucous carcinoma are exophytic or endophytic masses
characterized by hyperkeratosis, parakeratosis and nests of well
differentiated squamous epithelium with little atypia
extending into the dermis. The rete ridges have a bulbous appearance.
There is low mitotic activity.
This lesion slowly invades into underlying soft tissue and bone, if left
Small cell nonkeratinizing variant of squamous cell carcinoma may be
associated with overlying in-situ sqamous cell carcinoma and the tumour
infiltrates in cohesive nests in a backround of dense inflammation and
desmoplasia. Microscopically the lesion may resemble
merkel cell carcinoma.
Clear cell or signet ring
Site of tumour-
Tumour on the lip,eyelid,nose and ear are associated with high incidence
of recurrence and metastasis.
Size of tumour-
Tumour more than 20mm in diameter is at greater risk of recurrence and
(Grade I)- < 25%
(Grade II)- <50%
(Grade III)- <75%
(Grade IV)- >75%
Verrucous carcinoma has a high recurrence rate but rarely metastasises.
Spindle cell variant with desmoplasia and pseudo-angiosarcomatous squamous
cell carcinoma has a higher metastatic rate.
Tumour infiltrating in small nests, isolated strands, clusters and single
cells are at higher risk for recurrence and metastasis than those with
broad pushing borders.
thickness and risk of recurrence and metastasis -
2mm or less-
4mm and above-
More than 10mm-
Very high risk