Assist Prof. Dr. Mariana Fathy
Difference between Squamous & Basal Cell Carcinoma
Basal Cell Carcinoma (Rodent Ulcer)
Squamous Cell Carcinoma
Locally malignant tumor of basal layer of epidermis of skin
A malignant tumor of stratified squamous epithelium
Definition
- Skin
1- commonly face esp.
above a line drawn from the angle of the mouth to the lobule of ear
2- Extensor surface of arm
1- Skin
2- Mucous membrane lined by stratified squamous
epithelium
3- Mucous membrane on top of squamous metaplasia
Sites
-Prolonged sun exposure - Prolonged sun
exposure
- Squamous metaplasia Predisposing
factor
-Starts as a red papule then ulcerates. -The Ulcer is 1- Irregular
2- Inverted (rolled in) beaded edge
3- Necrotic floor 4- Firm base
a. Polypoid fungating mass
b. Ulcerative pattern 1- Irregular ulcer
2- Everted edge 3- Necrotic floor 4- Firm base
c. Infiltrative pattern Grossly
-Infiltration of the dermis by malignant masses
-The mass is formed of 1-peripheral columnar basal cells with palisade (parallel) arrangement
2-Central polyhedral cells -Other patterns are pigmented basal cell carcinoma, adenoid cystic basal cell carcinoma.
- Infiltration of the dermis or submucosa by whorled groups of malignant squamous cells forming cell nests - The cell nests are
formed of malignant squamous cells with central laminated keratin)
Microscopica lly
Assist Prof. Dr. Mariana Fathy
- The malignant
squamous cells show features of anaplasia.
- Inflammatory cells around tumors cell nests
Local spread only - Local spread
- Distant spread Spread
Pigmented (Melanocytic) Tumors
- Benign tumors originating from melanocyte are called naevocellular naevi.
- Malignant tumors originating from melanocyte are called melanoma.
1. Naevocellular Naevi (Pigmented Naevi Or Moles)
Origin:
- Naevi are either a. Acquired (common, appear in adolescence due to hormonal influence)
b. Congenital (rarely present at birth).
Gross picture:
- They are flat or slightly elevated lesions brown to black, less than 1 cm.
Microscopic picture:
- All naevocellular naevi are composed of nests of naevus cells.
- Naevus cells are oval with homogeneous cytoplasm and round vesicular nucleus.
The important histological variants of acquired naevi are:
1. Junctional naevus: The naevus cells form well- circumcised nests at the epidermal-dermal junction.
2. Compound naevus is the commonest type. In addition to the junctional activity as in Junctional naevi, it shows nests of naevus cells in the dermis.
3. Intradermal naevus shows no junctional activity. The lesion is mainly located in the upper dermis as nests of naevus cells.
Assist Prof. Dr. Mariana Fathy
2. Malignant Melanoma:
Origin:
Malignant tumor arising from melanocytes that can occur at all ages.
Etiology:
- The etiology is unknown but there is role of excessive exposure of white skin to sunlight.
- It may arise denovo or on top of previous nevi
- What are the clinical signs of transformation in nevi?
• Ulceration • Increase in size • Varigated colour • Lymph node enlargement
Sites:
- Skin, the common sites on the skin are the trunk (in men), legs (in women); other locations are face, soles, palms and nail-beds.
- Melanomas occur at any other sites such as oral and anogenital mucosa, conjunctiva and orbit.
Gross picture:
It appears as slightly elevated lesion with variegated pigmentation, irregular borders, increase in size.
Microscopic picture:
- Tumor cells:
- The tumor cells are large and arranged in sheets. They have amphophilic cytoplasm and pleomorphic nuclei with prominent nucleoli.
- Melanin: Melanin pigment may be present (melanotic) or absent (amelanotic melanoma).
- Inflammatory Infiltrate
Types (Clark`s classification) Two types of growth pattern:
1- Melanomas with radial pattern of growth:
a. Lentigo maligna melanoma.
- It is a melanoma insitu in which malignant cells spread along the basal layer of epidermis.
- It is slow-growing and has good prognosis.
b. Superficial spreading melanoma.
- Atypical melanocytes spread along all layers of epidermis - The prognosis is worse than for lentigo maligna melanoma.
Assist Prof. Dr. Mariana Fathy
- Dermal invasion occurs in a shorter time than lentigo maligna.
c. Acral lentigenous melanoma.
- This occurs more commonly on the soles, palms and mucosal surfaces.
- The neoplastic cells are deeply pigmented.
- The prognosis is worse than that of superficial spreading melanoma.
2- Melanomas with vertical pattern of growth (Nodular melanoma) - This often appears as an elevated and deeply pigmented nodule.
- This variant carries the worst prognosis.
- Spread by local, lymphatic, and blood.
Favorable Prognostic factors in melanoma 1- Breslow Depth of Lesion <1.5mm
2- Histology: superficial spreading melanoma.
3- Age: young.
4- Sex: female
5- Body site: extremities.
6- Mitotic index low
