Skin Pathology IV
Acne Vulgaris More severe in Males. Can be caused by: Drugs Occupational Exposures Cosmetics Tropical Climates Types: Non-Inflammatory: Open Comedones: Small, follicular papules containing a central, black keratin plug (blackheads) Closed Comedones: Follicular papules without a visible central plug. Inflammatory: Erythematous Propionibacterium Acnes: Administration of Antibiotics to individuals with inflammatory acne. 13-cis-retinoic acid: a synthetic Vitamin A derivative that has strong anti-sebaceous action and shows remarkable improvement. Causes Birth Defects.
Seborrheic Keratosis Common Epidermal Tumors Round, Flat, Coin-Like “tan, waxy plaques” that vary in diameter. Genetic: FGFR3, Receptor Tyrosine Kinase Histology: Hyperkeratosis Keratin-Filled Horn Cysts Invagination Cysts of Keratin Variable melanin pigmentation.
Acanthosis Nigricans Thickened, Hyperpigmented Skin with a “velvet-like texture” Appears in flexural areas. Genetic: FGFR3, Receptor Tyrosine Kinase 80% are benign. 20% are malignant gastrointestinal adenocarcinoma
Dermatofibroma Also called Benign Fibrous Histiocytoma Usually a history of previous trauma. Firm, Tan-Brown Papules, can be >1 cm Dimple-Sign: When sqeezed from edges, center dimples Histology: Pseudoepitheliomatous Hyperplasia: overlying the lesion Epidermis has hyperpigmented Basal Layer Peripheral Collagen Trapping – at edge of lesion Usually stays confined to the Dermis Stains: Factor XIIIa – Positive CD34 - Negative
Dermatofibroma Sacoma Protuberans (DFSP) Same general features as a Dermatofibroma. DIFFERENCEs: DFSP shows vacuoles or “fat trapping” on histology, which is clear. Where Dermatofibroma has “Collagen Trapping”, which is pink. DFSP is: Factor XIIIa Negative CD34 Positive CD34 Positive
Actinic Keratosis Caused by UV Light Considered Pre-Cancerous Squamous Cell Carcinoma Tan-Brown or Pink-Red Lesions with a rough, yellowish-brown or white scale. Can also look horned. Histology: Hyperkeratosis with Hyperplasia Dysplasia of the Epidermal Basal Layer (from the bottom, upward) Not Full Thickness!!! Full Thickness = Squamous Cell Carcinoma in situ Elastosis: The superficial epidermis contains thickened, blue-gray elastic fibers caused by UV-damaged Fibroblasts. Normal skin appendage areas.
Keratoacanthoma Arises from hair follicles in sun exposed areas in >50 year olds Description: Dome-Shaped, Crusty Lesions with Central, Keratin-Filled Crater that mimics a well-differentiated squamous cell carcinoma. Histology: Volcano Tx: Can spontaneously regress in 3-4 months Should be treated as though it is a Squamous Cell Carcinoma
Squamous Cell Carcinoma Cause: DNA Damage from UV Light Exposure Immunosuppression Squamous Cell Carcinoma in situ: Not invaded through the Basement Membrane. Appear as sharply defined, red, scaling plaques. Invasive Lesions: Nodular, Hyperkeratotic Scales Ulceration/Necrosis Invade the Basement Membrane Histology: Variable degrees of differentiation. Keratin Pearls May need immunostains to confirm the lineage.
Basal Cell Carcinoma Cause: Mutations that activate the Hedgehog Pathway. Sun-Exposed sites in fair-skinned, elderly patients. Epidemiology Locally aggressive cutaneous tumor. Most common invasive cancer in humans. Slow-Growing, Rarely Metastasize Histology: Variable types Pearly Papules with Telangiectasis (dilated blood vessels) Can have local invasion of bone or facial sinuses after many years of neglect = Rodent Ulcers Blue “basaloid” Cells. Peripheral Palisades Clefting: separation of tumor from surrounding stroma Embedded in mucinous Basal Cell Matrix = Basal Cell Stroma
Nevoid Basal Cell Carcinoma Syndrome Rare, Genetic Syndrome Causes Basal Cell Carcinomas at a very young age (12 years old) Gene: PTCH Tumor Suppressor Gene Born with a germline loss of function mutation in one PTCH Allele. Second Hit is required, by chance, causing early carcinoma formation.
Treatment: 13-cis-retinoic acid. Side Effects: Serious birth defects Acne Vulgaris Treatment: 13-cis-retinoic acid. Side Effects: Serious birth defects
Treatment: 13-cis-retinoic acid. Side Effects: Serious birth defects Acne Vulgaris Treatment: 13-cis-retinoic acid. Side Effects: Serious birth defects
Tan-Brown Waxy Plaques that vary in diameter. Seborrheic Keratosis Tan-Brown Waxy Plaques that vary in diameter.
Sebhorrheic Keratosis Tan-Brown Waxy Plaques that vary in diameter.
Sebhorrheic Keratosis Invaginations of Keratin (Invagination Cysts) Horn Cysts
Sebhorrheic Keratosis Invaginations of Keratin (Invagination Cysts) Horn Cysts
Velvet-Like, Thickened, Hyperpigmented Skin Flexural Areas Acanthosis Nigricans Velvet-Like, Thickened, Hyperpigmented Skin Flexural Areas
Velvet-Like, Thickened, Hyperpigmented Skin Flexural Areas Acanthosis Nigricans Velvet-Like, Thickened, Hyperpigmented Skin Flexural Areas
Dimple Sign: when squeezed from edges, center dimples. Dermatofibroma Dimple Sign: when squeezed from edges, center dimples. Factor XIIIa Positive CD34 Negative
Dimple Sign: when squeezed from edges, center dimples. Dermatofibroma Dimple Sign: when squeezed from edges, center dimples. Factor XIIIa Positive CD34 Negative
Peripheral Collagen Trapping Factor XIIIa Positive CD34 Negative Dermatofibroma Peripheral Collagen Trapping Factor XIIIa Positive CD34 Negative
Dermatofibroma Sarcoma Protuberans (DFSP) Vacuoles: “Fat Trapping” Not Collagen Trapping like Dermatofibromas
Dermatofibroma Sarcoma Protuberans CD34 + Stain Factor XIIIa Negative
Actinic Keratosis UV Pre-Cancerous Squamous Cell Carcinoma Tan-Brown or Pink-Red lesions with scales/horns.
Actinic Keratosis UV Pre-Cancerous Squamous Cell Carcinoma Tan-Brown or Pink-Red lesions with scales/horns.
Actinic Keratosis UV Pre-Cancerous Squamous Cell Carcinoma Tan-Brown or Pink-Red lesions with scales/horns.
Actinic Keratosis UV Pre-Cancerous Squamous Cell Carcinoma Tan-Brown or Pink-Red lesions with scales/horns.
Actinic Keratosis UV Pre-Cancerous Squamous Cell Carcinoma Not Full Thickness Hyperkeratosis, Hyperplasia, Parakeratosis, Dyspasia of Basal Cell Layer Elastosis
Actinic Keratosis UV Pre-Cancerous Squamous Cell Carcinoma Not Full Thickness Hyperkeratosis, Hyperplasia, Parakeratosis, Dyspasia of Basal Cell Layer Elastosis, Normal Skin Appendage Areas
Actinic Keratosis UV Pre-Cancerous Squamous Cell Carcinoma Not Full Thickness Hyperkeratosis, Hyperplasia, Parakeratosis, Dyspasia of Basal Cell Layer Elastosis
Acinic Keratosis UV Pre-Cancerous Squamous Cell Carcinoma Not Full Thickness Hyperkeratosis, Hyperplasia, Parakeratosis, Dyspasia of Basal Cell Layer Elastosis
Volcano Should be treated as though it is a Squamous Cell Carcinoma Keratoancthoma Volcano Should be treated as though it is a Squamous Cell Carcinoma
Squamous Cell Carcinoma In Situ Non-Nodular Sharply-Defined, Red, Scaling Plaques
Squamous Cell Carcinoma Invasive Nodular Hyperkeratotic Scales, Ulcerations
Squamous Cell Carcinoma Keratin Pearls Has no invaded the Basement Membrane Full-Thickness Dysplasia – In Situ
Blue “Basaloid” Cells Peripheral Palisades Clefting Basal Cell Carcinoma Blue “Basaloid” Cells Peripheral Palisades Clefting
Squamous Cell Carcinoma Keratin Pearls Invaded Basement Membrane Invasive
Squamous Cell Carcinoma Keratin Pearls Invaded Basement Membrane Invasive
Volcano Should be treated as though it is a Squamous Cell Carcinoma Keratoacanthoma Volcano Should be treated as though it is a Squamous Cell Carcinoma
Squamous Cell Carcinoma Keratin Pearls Invaded Basement Membrane Invasive Poorly Differentiated
Blue “Basaloid” Cells Peripheral Palisades Clefting Basal Cell Carcinoma Blue “Basaloid” Cells Peripheral Palisades Clefting
Pearly Papules containing dilated Sub-Epidermal Blood Vessels. Basal Cell Carcinoma Pearly Papules containing dilated Sub-Epidermal Blood Vessels. Can have ulcerations.
Squamous Cell Carcinoma Keratin Pearls Invaded Basement Membrane Invasive
Squamous Cell Carcinoma Keratin Pearls Has no invaded the Basement Membrane Full-Thickness Dysplasia – In Situ