Vascular tumours of the skin, skin infections, cutaneous mycoses Flashcards
Angiosarcoma definition
Rare blood vessel malignancy typically occurring in the head, neck, and breast areas
Usually in older adults, on sun-exposed areas
Very aggressive and difficult to resect due to delay in diagnosis
Associations of angiosarcoma
Associated with radiation therapy and chronic postmastectomy lymphedema
Stewart-Treves syndrome definition
Cutaneous angiosarcoma developing after chronic lymphedema
What is hepatic angiosarcoma associated with
Vinyl chloride and arsenic exposures
Bacillary angiomatosis definition
Benign capillary skin papules found in patients with AIDS
Caused by Bartonella infections
Frequently mistaken for Kaposi sarcoma, but has neutrophilic infiltrate
Cherry hemangioma definition
Benign capillary hemangioma commonly appearing in middle-aged adults
Does not regress
Frequency increased with age
Glomus tumour definition
Benign, painful, red-blue tumour, commonly under fingernails
Arises from modified smooth muscle cells of the thermoregulatory glomus body
Kaposi sarcoma definition
Endothelial malignancy most commonly affecting the skin, mouth, GI tract, respiratory tract
Epidemiology of Kaposi sarcoma
Classically seen in older Eastern European males, patients with AIDS, and organ transplant patients
Associations & type of infiltrate in Kaposi
Associated with HHV-8 and HIV
Lymphocytic infiltrates, unlike bacillary angiomatosis
Pyogenic granuloma definition & association
Polypoid lobulated capillary hemangioma that can ulcerate and bleed
Associated with trauma and pregnancy
Strawberry (infantile) hemangioma definition
Benign capillary hemangioma of infancy
Appears in first few weeks of life (1/200 births); grows rapidly and regresses spontaneously by 5–8 years old
Define Impetigo and the organisms involved
Skin infection involving superficial epidermis
Usually from S aureus or S pyogenes
Highly contagious
Clinical findings in impetigo and define bullous impetigo
Honey-coloured crusting.
Bullous impetigo has bullae and is usually caused by S aureus
Define Erysipelas & presentation
Infection involving upper dermis and superficial lymphatics, usually from S pyogenes
Presents with well-defined, raised demarcation between infected and normal skin
Define cellulitis
Acute, painful, spreading infection of deeper dermis and subcutaneous tissues
Usually from S pyogenes or S aureus
Often starts with a break in skin from trauma or another infection
define abscess
Collection of pus from a walled-off infection within deeper layers of skin
Offending organism is almost always S aureus
define necrotizing fasciitis
Deeper tissue injury, usually from anaerobic bacteria or S pyogenes
Pain may be out of proportion to exam findings
what does necrotizing fasciitis result in
Crepitus from methane and carbon dioxide production
“Flesh-eating bacteria”
Causes bullae & skin necrosis = violaceous colour of bullae, surrounding skin (Surgical emergency)
Staphylococcal scalded skin syndrome
Exotoxin destroys keratinocyte attachments in stratum granulosum only (vs toxic epidermal necrolysis, which destroys epidermal-dermal junction)
Commonly seen in newborns and children/adults with renal insufficiency
Clinical findings of staph scalded skin syndrome
Characterized by fever and generalized erythematous rash with sloughing of the upper layers of the epidermis that heals completely
⊕ Nikolsky sign (separation of epidermis upon manual stroking of skin)
Define herpes infection and where they occur
Herpes virus infections (HSV-1 and HSV-2) of skin can occur anywhere from mucosal surfaces to normal skin
These include herpes labialis, herpes genitalis, herpetic whitlow (finger)
Molluscum contagiosum
Umbilicated papules caused by a poxvirus
While frequently seen in children, it may be sexually transmitted in adults
Varicella zoster
Causes varicella (chickenpox) and zoster (shingles)
Varicella presentation
Varicella presents with multiple crops of lesions in various stages from vesicles to crusts
Zoster presentation
Zoster is a reactivation of the virus in dermatomal distribution (unless it is disseminated)
Hairy leukoplakia
Irregular, white, painless plaques on lateral tongue that cannot be scraped off
EBV mediated
Occurs in patients living with HIV, organ transplant recipients
Contrast with thrush (scrapable) and leukoplakia (precancerous)
Define Tinea (dermatophytes)
Clinical name for dermatophyte (cutaneous fungal) infections
Dermatophytes include Microsporum, Trichophyton, and Epidermophyton
Associated with pruritus
Dx of tinea
Branching septate hyphae visible on KOH preparation with blue fungal stain
Tinea capitis
Occurs on head, scalp
Associated with lymphadenopathy, alopecia, scaling
Tinea corporis
Occurs on body (usually torso)
Characterized by enlarging erythematous, scaly rings (“ringworm”) with central clearing
Can be acquired from contact with infected pets or farm animals
Tinea cruris
Occurs in inguinal area (“jock itch”)
Often does not show the central clearing seen in tinea
corporis
Tinea pedis
Three varieties (“athlete’s foot”): Interdigital most common Moccasin distribution
Vesicular type
Tinea unguium
Onychomycosis; occurs on nails
Tinea (pityriasis) versicolor organism and pathogenesis
Caused by Malassezia spp. (Pityrosporum spp.), a yeastlike fungus (not a dermatophyte despite being called tinea)
Degradation of lipids produces acids that inhibit tyrosinase (involved in melanin synthesis) = hyper/hypopigmentation, and/or pink patches can also occur from inflammatory response
Less pruritic than dermatophytes
When does tinea versicolor commonly occur and how does it appear on microscopy
Can occur any time of year, but more common in summer (hot, humid weather)
“Spaghetti and meatballs” appearance on microscopy
Tx of tinea versicolor
Selenium sulfide, topical and/or oral antifungal medications
