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