This document discusses skin tumors, including their causes, types, and characteristics of benign and malignant tumors. It notes that skin tumors are abnormal tissue growths that can be cancerous (malignant) or non-cancerous (benign). The causes include environmental toxins, genetics, diet and trauma. There are two main types - benign and malignant. Benign tumors grow slowly, are self-limited and do not infiltrate surrounding tissues, while malignant tumors grow rapidly, infiltrate surrounding tissues and can metastasize to other parts of the body. Examples of benign tumors include moles, cysts and lipomas, while basal cell carcinoma, squamous cell carcinoma and melanoma are examples of malignant skin tumors.

1. Tumor of the skin-types,
general features of Benign and Malignant tumor
with their histological characteristics
Presented by
Rubiat Ferdous
ID No. 19VS-JJ15
Reg. No. 41273

2. Contents
 What is skin tumor
Causes
Types
Tumor genesis
Malignant skin tumor
Benign skin tumor
Difference between MT & BT

3. Skin tumor
Skin tumors are abnormal growths of tissue that can be malignant
(cancerous) or benign (harmless). Skin tumors become extremely
common as people get older.

4. Causes of tumor
• Environmental toxins, such as exposure to radiation
• Genetics
• Diet
• Stress
• Local trauma or injury
• inflammation or infection

5. Tumor genesis (oncogenesis,
carcinogenesis)
 It is a multistep .
 These steps reflect genetic alterations that drive the progressive
transformation of normal cells into highly malignant derivatives
(cancer).
Steps of carcinogenesis:
• Initiation
• Promotion
• Progression
• Malignant conversion

6. Fig. Tumor genesis

7. Types of skin tumor
Benign skin tumor
Malignant skin tumor

8. Benign skin tumor
• Skin appendages or skin adnexa:
Hair follicles, sebaceous and sweat glands
• Common cyst – sebaceous cyst, dermoid cyst
• Soft tissue tumor – lipoma, fibroma, neurofibromatosis
• Epidermal tumor
• Moles (naevi)

9. Common cyst
Sebaceous cyst (epidermoid cyst)
 It is a retention cyst that is caused by the blockage of sebaceous
gland duct.
 Lined with stratified squamous epithelium contain a grayish white
material
 Often found on scalp , trunk face any hairy areas of the body except
the palm and the sole.

10. Fig. Sebaceous cyst

11. Clinical features:
• Slowly growing cyst and often painless
• If infected or inflamed, it becomes red, painful
and tender to touch
• Cyst forms a small, well defined cystic swelling usually fixed to
overlying skin at one point, freely movable, central punctum may be
seen
• Lesion may be solitary or multiple
• Sometimes it attains a large size

12. Dermoid cyst
• Dermoid cyst is lined by stratified squamous epithelium filled with
sebaceous material
• Dermoid cysts grow slowly and are not tender unless ruptured.
• They usually occur on the face, inside the skull, on the lower back,
and in the ovaries.

13. Fig. Dermoid cyst

14. Clinical features
Sequestration dermoid : present at birth but not appear except
after few years then cyst begins to extend.
Implantation dermoid : occurs secondary to punctured wounds
which displace some epithelial cells into SC tissues.

15. Treatment
• Excision of cyst

16. Soft tissue tumor
Lipoma
 Lipomas are benign aggregates of slowly growing painless adipocytes.
 Most common SC soft tissue tumor.

17. Fibroma
• Benign tumor composed of fibrous connective tissue.
• Can grow in all organs, arising from
• mesenchyme tissue

18. Fig . Fibroma

19. Treatment
• No treatment unless for cosmesis or liability to trauma
• Surgical excision under local anaesthesia or by
laser/radiowave/electrocoagulation/cryotherapy

20. Moles ( Naevi)
• Melanocytes migrate from neural crest to the basal epidermis
during embryogenesis.
Classifications :
• Lentigo
• Junctional
• Compound
• Intradermal

21. Fig. Moles

22. Malignant skin tumor
Basal cell carcinoma (BCC)
• Arise from basal layer of epidermis.
• Most common, 75% of skin tumors.
• Affects white skin, Male: Female=3:2
• Occurs on exposed parts: face, neck, scalp.
• Commonly Caucasian male older than 60 years.

23. Fig. Basal cell carcinoma

24. Etiological factors
• chronic exposure to sun light
• chemicals: arsenic, hydrocarbons
• ionizing radiation
• low immunity
• smoking

25. Types
• Nodulo-ulcerative : slow rising, nodular
• Pigmented BCC: ulcerative and deep brown to lack brown to black
nodule
• Superficial BCC: lightly pigmented patch.
• Sclerosing BCC: yellowish-white.
• BC nevus syndrome

26. Cont.. (MST)
• Squamous Cell Carcinoma
Arises from the malignant transformation of keratinocytes in the
epidermis.
Arise either in normal skin or in preexisting lesion as (actinic keratosis,
leukoplakia, radiation keratosis, scars.

27. Fig. Squamous Cell Carcinoma

28. Cont……….
Malignant Melanoma: MM
• result of the malignant transformation of melanocytes
• Occurs mainly in skin, also in eye, mouth , anus, vagina
Etiology :
• Positive family history in 5-10% of patients.
• Blue eyes, red hair, white skin, freckling.
• Benign and/or dysplastic melanocytic nevi
• Immunosuppression(in renal transplant).
• High Ultraviolet radiation .

29. Fig. Malignant Melanoma

30. General Features of Benign
and Malignant Tumor

31. CellCharacteristics
Benign tumor Malignant tumor
•Well-differentiated cells
• resemble normalcellsof
the tissuefrom whichthe
tumororiginated
•Cellsare undifferentiatedandoften
bearlittle resemblanceto the
normalcellsof the tissuefrom
which theyarose

32. Modeofgrowth
Benign
• Tumorgrowsby expansionanddoes
not infiltrate the surrounding
tissues; usuallyencapsulated
Malignant
• Growsat the peripheryandsends
out processesthat infiltrate and
destroy the surrounding tissues

35. Rate of Growth
Benign
• Rateof growth is usuallyslow.
Malignant
• Rateof growth is variableand
depends onlevelof differentiation;
the moreanaplasticthe tumor,the
fasterits growth

36. Metastasis
Benign
• Does not spread by metastasis
Malignant
• gains access to the blood and
lymph channel and metastasized
to the other areas of the body.