PATHOLOGY OF SKIN TUMORS

PATHOLOGY OF SKIN
TUMORS
TYPES OF BENIGN EPITHELIAL TUMORS OF SKIN
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Seborrheic keratosis.
Acanthosis Nigricans.
Fibroepithelial polyp.
Epithelial cyst (wen).
Adnexal (Appendage) tumors.
Keratoacanthoma.
MORPHOLOGY OF SEBORRHEIC KERATOSIS
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Variable melanin pigmentation
Hyperkeratosis.
Small keratin filled cysts (horn cysts & pseudohorn cysts) as invaginations of
keratin in to the tumor mass are present.
FIBROEPITHELIAL POLYP
 Fibro epithelial polyp / squamous papilloma / skin tag.
 A soft, flash colored, bag like, tumor attach to the skin surface.
 Morphologically, the fibro vascular cores covered by the benign squamous
epithelium.
 Ischemic necrosis may occur.
FIBROEPITHELIAL POLYP
KERATOACANTHOMA
It is, keratin filled crater, surrounded by proliferating epithelial cells, that extend upward
in a liplike fashion, over the sides of the crater and downward in to the dermis as
irregular tongues.
PREMALIGNANT AND MALIGNANT EPIDERMAL TUMORS
The types are-
I- Actinic keratosis.
II- Squamous Cell Carcinoma.
III- Basal Cell Carcinoma.
PREMALIGNANT AND MALIGNANT EPIDERMAL TUMORS
Actinic Keratosis:
Occurs in- Lightly pigmented individuals (fair colored).
- Chronic sun exposed areas.
Mostly occurs on- Face.
- Arms.
- Dorsum of hands.
- Occurs on lips known as
actinic cheilitis
SQUAMOUS CELL CARCINOMA
Predisposing factors in skin are-
- Exposure to sun light.
- Industrial carcinogens - (tar, oil).
- Chronic ulcers.
- Draining osteomyelitis.
- Old burn scar.
- Ingestion of arsenicals.
- Ionizing radiation.
- Immunosuppression.
- Xeroderma Pigmentosa
Predisposing factors in oral cavity - Tobacco chewing.
- Betel nut chewing.
SQUAMOUS CELL CARCINOMA
Invasive well differentiated carcinomaIn this, dermal /subcutaneous lobules & groups of atypical squamous cells with
pleomorphic & hyperchromatic to vesicular nuclei are found.
Keratin pearls are also formed.
1-gross
2- invasive ca.
3- keratin pearls
SQUAMOUS CELL CARCINOMA
POORLY OR UNDIFFERENTIATED CARCINOMAIt shows highly anaplastic round cells with foci of necrosis & dyskeratosis.
Lymphatic metastasis occurs in 5% cases.
Undifferentiated SCC-(dyskeratosis)
BASAL CELL CARCINOMA
Occurs in- Sun exposed areas.
- Lightly pigmented peoples (fair colored).
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Slow-growing.
Locally invasive, (after several years of neglect).
Rarely metastasize.
Early lesion appears as pearly papules.
Advance lesion found with ulceration.
MICROSCOPY
The tumor cells appear rounded with hyperchromatic nuclei.
The peripheral tumor cells formed palisading.
There is cleft formation occurred between tumor nest & surrounding tissue.
1- nodule with blood vessels,
2- nest & groups of basaloid cells in dermis,
3- palisading & cleft between tumor nodule & stroma
DISORDERS OF PIGMENTATION & MELANOCYTES
These consist of:
1- Vitiligo.
2- Albinism.
3- Freckle (ephullis).
4- Melasma.
5- Lentigo.
6- Nevi.
These consist ofa- Pigmented Nevus (mole).
b- Dysplastic nevus.
c- Malignant melanoma.
MELANOCYTIC NEVUS
(PIGMENTED NEVUS, MOLE)
Known as benign tumor or hamartoma.
Nevus cells are derived from melanocytes and present in clusters or nests.
DYSPLASTIC NEVI
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Appears as flat macule or papule with pebbly surface.
Occur on sun exposed or non exposed areas.
Typical irregularly pigmented lesion with disorderly proliferation of melanocytes
and dermal fibroses.
May transform in malignant melanoma.
DYSPLASTIC NEVI
MALIGNANT MELANOMA
 Common neoplasm
 Occurs on skin, oral mucosa, face, esophagus, meninges and eyes.
 Common in fair persons & arise from melanocytes or nevus cells.
 Can also form by dysplastic nevus
 Mostly associated with excessive exposure to sunlight.
MORPHOLOGY OF MALIGNANT MELANOMA
Morphologically there are two growth phases:
I- Radial (Initial phase)
II- Vertical growth (Later Phase)
MALIGNANT MELANOMA
1-melanocytic hyperplasia,
2-junct.nevus,
3-comp.nev with dysplasia,
4-radial- melanoma
5-vertical-malig.melonoma
MALIGNANT
MELANOMA
(GROSS-RADIAL & VERTICAL GROWTH OF MALIG. MELANOMA & HIGH POWER VIEW)
THE END
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