What is a nevus
Types of Nevi
Junctional Compound Intradermal
Tend to be flat with nests at the junction of the epidermis and dermis
Typically a central raised area surrounded by flat with nests at the junction of the epidermis and dermis as well as in the dermis
Nests in the dermis only that often protrude
Clinical Dysplastic Nevi signs
Typically larger, flat and pebbly or target-like with irregular pigmentation and border
Under histology, what might we see a dysplastic nevi doing?
Cytologically it grows radially (sideways) getting larger with darker nuclei
Sign of dysplasia in Nevi growth,it is a growth into the dermis, usually presenting as a nodule
ABCs of tumor
A - Assymetry B - Border C - Color D - Diameter (larger typically) E - Evolving or changing
Causes of dysplastic Nevi
1. Many sunburns in life 2. 10-15% had familial connections with it 3. Mutations that inhibit the RB tumor supressor gene are common in familial and sporadic melanomas. 40% have CDKN2A abnormalities
Age, location, description for Seborrheic Melanoma
Middle aged or older, typically presents on the trunk head and neck and presents as a round, flat, waxy lesion that varies in size with mild inflammation underneath
Fibroepithelial polyp alternative names
Also called Acrochordon, skin tag, and squamos papilloma
Age, location, description of fibroepithelial polyp
Middle aged folks, usually on neck, trunk, and face, and typically flesh colored, bag-ike with a thin stalk
Basic idea of the epidermal inclusion cyst
When we see "trich" in the name, what do we know?
Basic idea of the dermoid cyst
multiple epidermal appendages
Basic idea od Steatocystoma
Adnexal tumor making it uncommon. Jigsaw puzzle piece look with basaloid proliferations, common on the forehead
Epithelial proliferation of the hair shaft, this is an uncommon adnexal tumor
Sebaceous adenoma pilomatrixoma
Adnexal tumor in the sebaceous gland that is calcified, shows up blue on a stain and the cells lose their nuclei
Prcursor to SCC caused by sun damage to skin. Usually small, less than 1cm with a rough sandpaper consistency, sometimes with a cutaneous horn Hyperkeratosis seen on histology
Squamos Cell Carcinoma
Second most common tumor on sun exposed skin 5% metastasize Presents as a red scaling plaque with full thickness dysplasia. They can become invasive, turning nodular and may ulcerate
Cup shaped, well differentiated SSC that often regresses spontaneously. Labeled as controversial for whatever reason
Basal Cell carcinoma
Most common type of sun exposed skin cancer that is slow growing. Also rarely metastasizes. Presents as pearly papules that may ulcerate or appear melonocytic, making it easily confused with moles. Histologically presents as islands of basophillic cells, hyperchromatic nuclei.
Basal Cell Nevus or "Gorlin Syndrome"
Multiple BCC before the age of 20 with possible systemic changes such as intracranial calcification, cleft lip/palate, and vertebral/rib abnormalities. This is an autosomal dominant condition involving the PTCH - 2hit gene
Also called benign fibrous histocytoma. Presents in adults, particularly on the legs Firm brown papules, thought to be related to trauma and altered collagen. Presents on histology as non-encapsulated, presence of spindle cells with overlying epidermal hyperplasia with collagen "traps."
Flesh colored nodule that is firm and goes down into the fat with a radial spoke look on histology
Cutaneous T cell lymphoma that usually presents in patients over 40 on the trunk as scaly patches, plaques, or nodules that can become ulcerated
Posible result of Mycosis Fungoides where malignant T cells in the blood cause diffuse erythroderma
Rare dermal tumor involved with increased mast cells. In children, it only affects the skin, causing urticaria and lesions that appear shortly after birth. In adults however, we see a systemic disease with a poor prognosis. Morphology of this is variable, but presents typically with ovoid uniform balls and fried egg on histology. Use Giemsa to locate mast cells.
Acute inflammatory dermatoses
Acute inflammation process that causes urticaria via mast cell degranulation and microvascular hyperpermeability. We see this as wheals that can be puritic with superficial perivascular infiltrate
"To boil over"
Red, papulovesicular with crusted oozing lesions, puritic that can develop in to raised scaling plaques with hyperkeratosis.
Acute contact dermatitis
Puritic, edematous, oozing plaques that can blister. Tis is an impetiginization hat presents with acanthosis and increased keratin layers with spongiosis. Noted clinically with intraepidermal collection of vesicles
Uncommon hypersensitivity to drug or infection. Clinically it varies, but we see macules, papules, vesicles, targetoid and eroded centers
Conditions associated with erythema multiforme
Herpes simples Typhoid Leprosy Coccidiomycosis
Drugs that can cause erythema multiforme
Sulfonamides PCN barbiturates antimalarials
A chronic inflammatory dermatosis that is well demarcated, salmon colored plaque with silver color from scaling
Histology of psoriasis
Extensive parakeratosis, thinned stratum granulosum, Auspitz sign munro microabcesses epidermal hyperplasia
Associated with psoriasis, appearence of multiple bleeding points when scale is lifted
Associated with psoriasis, neutrophils appear beneath the stratum corneum
Blistering disease where autoantibodies cause breaking of intercellular attachments of epidermis. Basal layer acatholysis with ulcerated mucosal blister and eroded plaques. Typically presents on the scalp, face, axilla, and groin
Staining for Pemphigus Vulgaris
We'd see immunoglubuilin deposition along plasma membrane with a reticular or fish net pattern
Typically in older patiens, presents as dense bullae , large up to 2cm or more that do not rupture easily. Typically on inner thighs, flexor forearms, and 10-15% of people have oral lesions. The DEJ hemidesmosomes are attacked in this condition. No acantholysis, important in distinguishing against Vulgaris.
Histology of Bullous pemphigoid
Subepidermal nonacontholytic-linear deposits of immunoglobulin and complement along the epidermal-dermal junction
AKA Erythema Nodosum. This is an inflammatory reaction that affects the connective tissue between fat lobules. These are very painful erythematous plaques and you need a deep biopsy to learn more.
Acute contact dermatitis
Note the intraepidermal collections of vesicles
Acute inflammatory Dermatosis
Note the whealing puritis and perivascular involvement
Basal Cell Carcinoma
Note in the histology how the upper epidermis is pulled off
Note the collagen nests
Note the radial appearence on histology
Note the ovoid, uniform appearence and the Mast cell stainong on the right side Giemsa stain
Note the erythematous and ulcerated plaques
Note the eroded plaques
Note the silver scaling with pustules and erythema and thinned stratum granulosum
Note how closely it resembles a melanoma