The document discusses malignant skin tumors, detailing risk factors such as chronic sun exposure, immunosuppression, and genetic conditions like xeroderma pigmentosum. It highlights three main types of skin cancer: squamous cell carcinoma (SCC), melanoma, and basal cell carcinoma (BCC), outlining their characteristics, morphology, and associated risk factors. Melanoma is noted as the deadliest skin cancer, while BCC is described as slow-growing and locally invasive, primarily affecting white individuals.

1. MALIGNANT SKIN TUMORS
DR.N.MANJULA

4. RISK FACTORS
Chronic sun exposure: Prolonged exposure to ultraviolet (UV)
radiation.
1. Ultraviolet A ( longer wavelength)
2. Ultraviolet B (UVB)( Short wavelength) leads to DNA damage
and mutation.
Chronic Immunosupression:
Eg, Chemotherapy, transplation and sun exposure leads to
increased susceptibility to infections by oncogenic viruses.
Others: Tars,oils- chemical carcinogens.

5. • XERODERMA PIGMENTOSUM: Genetic disorder with Inherited mutation in DNA
repair genes leads to Increased susceptibility to skin cancers

6. SQUAMOUS CELL CARCINOMA(SCC)
• Second most common tumor arising on the sun exposed
sites.
• Males have slightly higher preponderance than females.
• Often White skin individuals where the etiology is almost
always UVR induced.
• Brown- or black-skinned persons can develop SCC from
numerous etiologic agents other than UVR.

9. MALIGNANT MELANOMA
• It is the deadliest of all skin cancers.
• It occurs commonly on the skin surface.
• It can arise from oral mucosa, anogenital mucosa, meninges, uveal
tissue, Gastro-intestinal tract, etc.
• Though it has the suffix “oma”, melanoma is a malignant tumour

10. Risk factors
• The risk factors for melanoma are:
• Hereditary – can be inherited as autosomal dominant trait with
variable penetrance.
• Ultraviolet (UV) radiation exposure
• Sunlight exposure
• Fair skin
• Severe sunburns

11. Etiopathogenesis
• The driver mutations in melanoma involve the cell cycle control, pro-
growth pathways and telomerase.
• Some common mutations involving cell cycle control genes are
CDKN2A which in turn encodes tumour suppressors like p15, p16 and
ARF.
• Mutations involving the pro-growth pathways include activating
mutations in BRAF, loss of PTEN, loss of function mutation of NF1.
The common mutation involving telomerase is TERT (telomerase
reverse transcriptase) gene.

12. Morphology
• Melanomas show varying colours like black, brown, red, blue and
gray.
• Melanomas have irregular borders.
• The benign counter-part or nevi are usually small, and show smooth
and regular borders and uniform colour.

16. Basal cell carcinoma (BCC)
• It is a malignant epidermal tumour which is slow-growing, locally invasive, and
mainly affects white people.
• Though it is malignant, metastasis is extremely rare.
• However it is locally invasive and destructive hence also referred to as “rodent
ulcer” . This is the reason for significant morbidity in affected individuals.
• “Majority of the BCC’s occur in head and neck region.
• The most common location would be above the line which is drawn from the
angle of mouth to the pinna of the ear

17. Clinically , the appearance of the tumor vary and they can be nodular, cystic, ulcerated, sclerotic,
superficial or pigmented types. The ulcerated variety is the one which is commonly referred to as
rodent ulcer!
Gross: Nodulo- ulcerative is the most common morphological type. The lesion is typically an
elevated lesion with ulcer surrounded by rolled out edges.

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