Handout

SKIN DISEASES: An Integrated Clinicopathologic

Approach- Med 1

Dr. M. G. Joseph, Professor

Dept. of Pathology, LHSC

Specific Objectives

• Recognize common skin tumours, basics. An integrated clinicopathologic approach

• Summarize important points learned from previous and upcoming clinical

lectures…where to focus (few clinical images from previous lectures are used to re-emphasize concepts)

Dermatology Mini Atlas WebCT

For Self Study/ Practice Review

• Important for end of the course Image Quiz examination

Skin Tumours Basics

Behaviour • Benign Tumour • Malignant Tumour

Histogenesis (origin) • Epidermal • Dermal • Adnexal

Primary vs metastatic tumour

SKIN TUMOURS (Histogenesis)

• Epidermis - Squamous cells - Basal cells - Melanocytes

• Adnexal tumours • Dermal (Mesenchymal)

- Collagen - Smooth muscle - Blood vessel - Nerve

• Lymphoma/leukemia

• Metastatic tumours

How to Describe a Lesion SCALDA for Tumours

• Size

• Color

• Arrangement (configuration)

• Lesion morphology

• Distribution

• Always check hair, nail, mucosa, intertriginous areas

Skin Cancer Basics

• Skin cancer is the most common form of cancer in human.

• It is estimated that approximately 75,000 canadians will develop skin cancer every year

• 3 histologic types account for about 99% of all skincancers.- Basal cell ca, Squamous cell ca, Melanoma

• All are caused by chronic sun exposure - Cumulative amount important for squamous cell ca - Intermittency and amount of exposure important

for basal cell ca and melanoma

Skin Cancer, Common Types

• Basal cell carcinoma - Most common type of skin cancer, 80% of all cancers, sun damaged skin, elderly

- Several subtypes of BCC, nodular most common

- Slow growing, locally invasive, do not metastasize

- Histology- malignant proliferation of basaloid cells of epidermis

Basal cell carcinoma 2 Common subtypes

Nodular UlceronodularA well circumscribedPearly white/pink nodule Ulcerated nodule

with surface telengiectasia with rolled edges

Nodular Basal Cell Carcinoma

A well circumscribed nodule, origin from basal cells of epidermis and infiltration into dermis

Basal cell carcinoma

B

C

A

Nests of basaloid cells (A), peripheral palisading of nuclei (B), loose fibrous stroma (C)

Multiple BCCs in a young patient

Gorlin Syndrome

Multiple BCCs Young patient Back

Look for …….. Palmar pits Bifid ribs

From: Gorlin, 2004.

Nevoid BCC (Gorlin Syndrome)

• Autosomal dominant, 0.4% of all BCC cases

• Most cases reflect mutation in the patched gene (PTCH) chromosome 9q22-q31 cause upregulated cell proliferation

• 2% of patients under age 45 years with BCC have NBCC syndrome

Gorlin Syndrome

1. Predisposition to various tumours Odontogenic keratocysts Medulloblastoma brain Fibromas of ovary, heart

2. Other skin manifestations Palmar and plantar pits Multiple epidermal cysts

3. Cleft lip/ palate, macrocephaly

Skin Cancer, Common Types

• Squamous cell carcinoma - Second most common cancer of skin - Sun damaged skin, elderly - Locally invasive, can metastasize (5-10%) - Histology: malignant proliferation of epidermal keratinocytes. - squamous cell carcinoma is of 2 types

• Insitu squamous ca (Bowen’s disease) • Invasive squamous ca

Bowen’s disease - insitu SCC

Sharply demarcated red scaly patch

Proliferating malignant keratinocytes confined to epidermis Origin - epidermal squamous cells

Invasive Squamous Cell Carcinoma

SCALDA skin colored indurated and ulcerated nodule on lip

Invasive Squamous cell carcinoma

B

A

Origin- from squamous epithelium, invades into dermis Malignant squamous cells (A) invading dermis (B)

Skin Cancer

• Malignant Melanoma – Malignant tumour of melanocytes

- Least common, most deadly type of skin cancer

Common Benign/premalignant Tumours of skin

• Seborrheic keratosis

• Corn, Skin tag

• Wart, Molluscum contagiosum

• Solar keratosis (premalignant)

• Dermatofibroma

• Epidermal cyst, Pilar cyst

• Keratoacanthoma (benign vs malignant, contraversial)

Seborrheic keratosis A common benign epidermal tumour

SCALDA

multiple brown scaly papules /plaques stuck on appearance on the trunk

Seborrheic keratosis pigmented type

Single well circumscribed brown scaly papule/nodule, Stuck on (pigmented sebka)

Skin tag, benign

Soft skin colored pedunculated papule/nodule

Corn, benign: painless keratotic papule, clear core, central depression

Thick stratum corneum (hyperkeratosis)

Wart: scaly verrucous flesh colored papule/nodule, red spots (arrow)

HPV Virus cause Hyperkeratosis, acanthosis, viral changes in cells (arrow) dilated vessels (red arrow)

Molluscum Contagiosum

Multiple umbilicated skin coloured sma papules Pox virus- cause

Actinic Keratosis (premalignant squamous lesion)

Multiple poorly demarcated reddish brown rough scaly papules and plaques on sun damaged skin

Actinic Keratosis

Parakeratosis (arrow)

B

For information only

A Atypical keratinocytes (A) Sun damaged dermis (B)

Keratoacanthoma (Benign ?)

1.5 cm well circumscribed skin colored nodule with central keratin filled Crater Rapid growth in few wks Spontaneous remission in few weeks

SCALDA

Keratoacanthoma vs SQCC

Clinical similarity, excise completely

Keratoacanthoma Squamous cell ca

Benign proliferation of Malignant proliferationkeratinocytes of keratinocytes

2 common benign skin cysts basics

Epidermal cyst (most common, face, neck, trunk)

Pilar cyst (scalp)

Cyst: sac filled with fluid or semisolid material (fluctuant) and is lined by epithelium

Epidermal cyst (most common benign skin cyst in dermis)

Slowly growing, painless, round, soft, mobile, fluctuant skin coloured nodules, may have a central punctum

Inflammed epidermal cysts (painful)

Punctum

Pilar cyst (second common skin cyst scalp)

Lining epithelium and keratin are different from epidermal cyst, clues for pathologist

Common Benign Dermal Tumours - origin

Dermatofibroma - fibroblast

Lipoma - lipocytes (fat cells)

Hemangioma - blood vessel

Neurofibroma - nerve

Pyogenic granuloma -blood vessel

This firm nodule is present for years. Dermatofibroma (benign

dermal tumour)

Tan firm papule, may be pigmented, dimple sign

Firm well circumscribed brownish red nodule on le

Dermatofibroma

Dermatofibroma (Dimple sign/ Fitzpatrick’s sign)

Benign proliferation of fibroblasts

Hemangioma Benign vascular tumour, congenital or acquired, small or large, flat or elevated

Cherry red colour

Pyogenic granuloma, benign (Lobular capillary hemangioma)

A pedunculated red nodule that bleeds, history of trauma

Vascular proliferation

Melanocytic Tumours

Melanocytic Neoplasia

• Benign nevus - lentigo simplex, junctional N, compound N, intradermal N

- Spitz N, Blue N, Halo N, Congenital N.

• Dysplastic nevus (atypical nevus)

• Malignant melanoma (insitu/invasive)

Evolution of Benign Nevus

• Lentigo simplex

• Junctional nevus

• Compound

• Intradermal

Nevus evolution

Junctional, Compound, Intradermal N

Lentigo simplex JN CN IDN

Life cycle of nevus

Compound nevus

2 pigmented lesions present for the past 10 years. What are they?

Blue nevus Halo nevus

Halo nevus (Regressing Nevus)

This patient has dysplastic nevus syndrome

Dysplastic nevus ABCD criteria

Dysplastic Nevus- Clinical

• Large size (5mm-12mm.) - 72%

• Irregular

• Asymmetry

• Irregularity of colour-84%

• Presence of a central papule and peripheral macular component

Dysplastic Nevus

• Dysplastic nevus syndrome: Affected people develop large number of dysplastic nevi and are associated with increased incidence of melanoma

• Isolated dysplastic nevi in patients without personal or family history of melanoma is main source of controversy, incidence 5-20%

For information only

Dysplastic nevus

For information only This Nevus shows architectural and cytological atypia

Dysplastic Nevi –Key Points

• Considered as a risk marker for melanoma, risk increases with number of nevi. • May be potentially a precursor for melanoma, dysplastic nevus present adjacent to an invasice melanoma in 36% of melanoma cases.

• Individual lesions, sig . unknown • Patients with many lesions should be periodically monitored

Malignant melanoma, basics Objectives

• How to diagnose melanoma

• List 4 types of melanoma

• List 5 prognostic factors of melanoma

How to Diagnose Melanoma (ABCDE check list)

• Asymmetry

• Border irregularity-notched border

• Color variegation-red, white, blue

• Diameter greater than 6mm

• Elevation/enlargement (recent)

4 Types of Melanoma

• Lentigo maligna (insitu), lentigo maligna melanoma (invasive)

• Superficial spreading melanoma, in situ and invasive

• Acral lentiginous melanoma, in situ and invasive

• Nodular melanoma (always invasive)

4 Types of Melanoma (important slide)

The most common form of melanoma: -in African-Americans is acral lentiginous Melanoma -associated with chronically sun-exposed skin is lentigo maligna melanoma

1 Superficial spreading M, leg

2 Nodular M

Nodular melanoma, small3 Acral lentiginous M

4. Lentigo maligna M face

Normal to insitu melanoma evolution

Normal Pagetoid intraepidermal spread

Invasive melanoma - invasion into dermis Breslow thickness- prognostic factor 1

Breslow thickness: measured from epidermal granular layer to deepest melanoma cell in dermis

Clark level l – V - prognostic factor 2

I II

III

IV

V

I Confined to epidermis (in situ) II Invasion of papillary dermis III Fills the papillary dermis

IV Invasion of reticular dermis V Invasion of subcutaneous fat