Dermatopathology (Puthoff) Flashcards
What is the general structure of human skin?
Epidermis
Dermis
Subcutaneous tissue
What are different cell types within the epidermis?
Squamous epithelial cells (keratinocytes)
Melanocytes
Dendritic cells (Langerhans cells)
Merkel cells
What are different cell types in the dermis?
Lymphocytes Lymphatics Small blood vessels Afferent and sensory nerve fibers Adnexal components (hair shafts and sebaceous glands)
The bottom layer of the epidermis contains epidermal ridges called _______ ______. These will interconnect with the _______ _______ on the dermis.
Rete pegs
Dermal papillae
What are the 2 layers of the dermis?
Papillary layer (contains dermal papillae) Reticular layer
What are the layers of the epidermis (from superficial to deep)?
Stratum corneum Stratum lucidum Stratum granulosum Stratum spinosum Stratum basale
***Mnemonic = Come, Let’s Get Sun Burned
This layer of the epidermis is only in thick skin (soles and palms).
Stratum lucidum
Major proteins formed within keratinocytes are ________. These are intermediate filament proteins making up the cytoskeleton of the cells.
Keratins
Antibodies to various _________ are used in pathology to identify keratinocytes (ie, CK AE1/3).
Cytokeratins
These are structures that are derived from the skin and usually adjacent to it. Functionally this includes hair follicles, sebaceous and sweat glands. In a larger, macroscopic sense of the skin, it also includes specialized structures like nails of fingers and toes.
Skin adnexa (appendages)
What are the main disorders of pigmentation and melanocytes?
Freckle
Lentigo
Nevi
Melanoma
These are the most common pigmented lesions of childhood in lightly pigmented individuals. Also called an Ephelis.
Freckle
This is a benign, localized melanocytic hyperplasia.
Lentigo
This type of nevus (non-medical = mole) that can be caused by acquiring activating mutations in Ras signaling pathway.
Melanocytic/Pigmented Nevi
This type of nevus may be a direct precursor of melanoma.
Dysplastic Nevi
This type of nevus develops at the dermal/epidermal junction.
Junctional Nevi
A Junctional Nevus can become deeper and develop into this. This type of nevus is also at the junction but also nests into the reticular dermis.
Compound Nevi
This type of nevus is deep dermal and sometimes subcutaneous growth around adnexa, neuromuscular bundles, and blood vessel walls. It is present at birth, and large variants have increased melanoma risk.
Congenital Nevus
This type of nevus has non-nested dermal infiltration, often with associated fibrosis. It is a black-blue nodule, often confused with melanoma clinically. Highly dendritic, heavily pigmented and painful.
Blue Nevus
This type of nevus has fascicular growth, and consists of large, plump cells with pink-blue cytoplasm and fusiform cells. Common in children, red-pink nodule often confused with hemangioma clinically.
Spindle and Epithelioid cell (Spitz) Nevus
This type of nevus has lymphocytic infiltration surrounding the nevus cells. It is identical to ordinary acquired nevi, and there is a host immune response against nevus cells and surrounding normal melanocytes.
Halo Nevus
In Dysplastic nevi, an important feature is the presence of…
Cytologic atypia
This is the most deadly of all skin cancers. It is strongly linked to sun exposure and is inherently immunogenic.
Malignant melanoma
What is the ABCDE rule for melanoma?
A = Asymmetry B = Border C = Color D = Diameter (greater than 6 mm) E = Evolution
This measurement will look at the thickness of melanoma. Under 1 mm is a good prognosis.
Breslau Measurement
What are the types of benign epithelial tumors?
- Seborrheic keratoses
- Acanthosis nigricans
- Fibroepithelial polyp
- Epithelial inclusion cyst
This type of benign epithelial tumor can be pigmented or pale, also often irritated due to picking at it. Very common in older individuals, mostly on the trunk. Quite superficial/flat to round/coin-like, waxy exophytic lesions.
Seborrheic keratoses
This sign occurs when crops of Seborrheic keratoses suddenly appear. Can be a sign of cancer.
Leser-Trelat sign
This type of benign epithelial tumor consists of dark-thickened skin in creases or flexural areas. Has velvet-like texture.
Acanthosis nigricans
What percentage of Acanthosis nigricans is benign, and is acquired (obesity, DM, etc) or inherited (rare, AD inheritance)?
80%
What percentage of Acanthosis nigricans is associated with malignancy, most commonly GI carcinomas?
20%
This type of benign epithelial tumor is also known as a skin tag.
Fibroepithelial polyp
This type of benign epithelial tumor is very common, and are sebaceous cyst, or wen. These can rupture and the pus is very smelly. Have to excise with the capsule or they can reoccur.
Epithelial inclusion cyst
This category of cutaneous tumors can arise from hundreds of neoplasms.
Adnexal (appendage) tumors
What type of tumors are within the premalignant and malignant epidermal tumor category?
Premalignant = Actinic keratosis
Malignant = SCC and BCC
BCC can often present small red blood vessels, which is called…
Telangiectasis
In a normal cell, SHH will bind to ______ and dissociates ______. This allows activation of gene expression in normal development and tissue homeostasis. However, in BCC there is mutated _______, causing _______ to be permanently dissociated and active. This leads to unregulated cell division and abnormal growth.
PTCH
SMO
PTCH
SMO
What is the mnemonic and terms for so-called “painful” skin lesions?
GLENDAB
G = Glomus tumor (occurs under nail) L = Leiomyoma (angio-type) E = Eccrine spiradenoma N = Neurofibroma D = Dermatofibroma A = Angiolipoma B = Blue rubber bleb nevus
This type of tumor of the dermis refers to a heterogenous family of morphologically and histogenetically related benign dermal neoplasms of uncertain lineage. Usually seen in adults and often occur on legs of young and middle-aged women. Lesions are asymptomatic or tender and may increase or decrease in size over time.
Benign Fibrous Histiocytoma (Dermatofibroma)
What type of tumor of the dermis can often have a history of antecedent trauma? Suggesting an abnormal response to injury and inflammation (ie, like in a hypertrophic scar or keloid).
Benign Fibrous Histiocytoma (Dermatofibroma)
This tumor of the dermis is a well-differentiated, primary fibrosarcoma of the skin. They are slow-growing, and although they are locally aggressive and can recur, they rarely metastasize.
Dermatofibrosarcoma Protuberans
Describe the molecular hallmark of Dermatofibrosarcoma Protuberans.
Translocation involving the genes encoding collagen 1A1 (COL1A1) and platelet-derived growth factor-B (PDGFB). The resulting rearrangement juxtaposes the COL1A1 promoter sequences and the coding region of PDGFB and leads to over expression and increased secretion of PDGFB, which drives tumor cell growth through an autocrine loop.