Sec 9 Disorders of Dermal Connective Tissue Flashcards
It is a complex network of different components, responsible for determining and maintaining tissue architecture, and for mediating a number of important biological events composed of a large number of diverse protein families.
Extracellular Matrix
The most widely distributed and the most extensively characterized form of collagens, accounts for approximately 80% of the total collagens of adult human dermis.
Type I collagen
Represents approximately 10% of the total collagens in the adult human dermis. It is composed of three identical α1(III) chains, distinguished from the chains of type I collagens by a relatively high content of hydroxyproline and glycine and the presence of one cysteine residue.
Type III Collagen
It is a typical component of basement membranes, where it forms a lattice rather than the fibers characteristic of dermal collagens.
Type IV Collagen
It forms specific microfibrils in the dermis
Type VI Collagen
The major, if not the exclusive, component of the anchoring fibrils at the dermal–epidermal junction, has an unusually long triple-helical region of approximately 450 nm
Type VII Collagen
These are basement membrane-associated collagens. They have been called multiplexins because they contain multiple noncollagenous domains in their collagenous sequences.
Type XV and XVIII Collagens
It is a transmembrane protein anchored in the membrane of basal keratinocytes, with an intracellular domain and a large extracellular domain, or ectodomain, which is a component of the basement membrane at the dermal–epidermal junction.
Type XVII Collagen
Chronic autoimmune disease characterized by sclerosis of the skin
Morphea
Stage: begins as erythematous plaques or patches, sometimes with a reticulated appearance then later hypopigmented sclerotic plaques develop at the center of the lesion, surrounded by an erythematous or violaceous border
Inflammatory stage of Morphea
Forms a subfamily of similar interrelated collagens resulting from various assemblies of three different types of α chains, α1(V), α2(V), and α3(V).
Type V collagen
Stage: there is loss of hair follicles, producing alopecia; over months to years, the sclerotic plaque softens and becomes atrophic with hypo- or hyperpigmentation
Atrophic stage of Morphea
Stage: Pain and/or itching can precede the initial skin findings; sclerosis develops centrally, which turns into a shiny white color, as lesions expand with surrounding hyperpigmentation
Sclerotic stage of Morphea
Changes in atrophic stage of Morphea
cigarette paper wrinkling - papillary dermis
cliff drop - dermal
deep indentions - subcutis or deeper
Represents oval to round lesions undergoing the stages of activity that are not diffuse enough to meet criteria for generalized disease
Circumscribed morphea
Characterized by more than or equal to four lesions on at least two of seven different anatomic sites (head-neck, right/left upper extremity, right/left lower extremity, anterior/posterior trunk)
Generalized morphea
Generalized morphea subtypes
- isomorphic - coalescent plaques inframammary fold, waistline, lower abdomen, proximal thighs
- symmetric - symmetric plaques circumferential around breasts, umbilicus, arms, and legs
- pansclerotic - circumferential involvement of majority of body surface area (sparing ngertips and toes), affecting skin, subcutaneous tissue, muscle or bone
Usually affects the extremities and face, but it can occur on the trunk which may follow Blaschko’s lines
Linear morphea
May present as an atrophic band linear plaque on the forehead, extending to the scalp (where cicatricial alopecia occurs), brow, nose, and lip.
En Coup de Sabre
Characterized by a slowly progressive, unilateral atrophy of skin, soft tissues, muscles, and/or bony structures. The atrophy may be accompanied by classic linear morphea lesions on the face or elsewhere.
Progressive Hemifacial Atrophy
Involves the deep dermis, subcutaneous tissue, fascia, and muscle. Plaques are poorly circumscribed and symmetrical with the skin feels thickened and bound down to the underlying fascia and muscle; a “groove sign” (depression) may be present at the site of tendons and ligaments
Deep morphea
A related disorder presenting with rapid onset of symmetric areas of pain and edema, usually on the extremities; may occur with cutaneous induration similar to morphea, or remain without skin involvement.
Shulman syndrome
Provides a complete assessment of the extent of disease, including depth of involvement and disease activity of Morphea
Magnetic Resonance Imaging
A sensitive tool to evaluate or monitor tissue thickness, loss of subcutaneous fat and muscle, or other architectural alterations in Morphea
Ultrasonography
Presents as polygonal papules and porcelain-white plaques with atrophic fragile skin, fissures, telangiectasias, purpura, erythema, erosions, and different degrees of sclerosis are present in the anogenital area with severe itching
Lichen sclerosus
Frequently causes intractable itching and soreness, dyspareunia, dysuria, discomfort with defecation, or genital bleeding and, with time, may lead to destructive scarring; gradual obliteration or synechiae of the labia minora and clitoris, as well as stenosis of the introitus, may also result
Anogenital lichen sclerosus
Extragenital lichen sclerosus
Thigh
Neck
Trunk
Lips
Associated autoimmune diseases with lichen sclerosis
Autoimmune thyroid disease Alopecia areata Pernicious anemia Morphea Vitiligo
Histopathology: shows an atrophic epidermis and a lichenoid infiltrate at the dermal–epidermal junction. Papillary edema is usually seen in early lesions but is gradually replaced by fibrosis with homogenization of acid mucopolysaccharides as the lesion matures.
Lichen sclerosus
Main complication in females with Lichen sclerosus
Squamous cell carcinoma
Most frequent complications in males with Lichen sclerosus
Painful erection
Urinary obstruction
The single most effective treatment of LS
Ultrapotent topical corticosteroids limited, generally to 4–6 weeks
Appears as well-circumscribed pink to purple or hyperpigmented firm nodules or plaques. Their surface is usually smooth, but can be nodular and borders are often smooth, but can be irregular. There is a predilection for developing at sites of increased tension, such as the shoulders, sternum, mandible, and arms; also commonly affect the earlobes. They are often painful, hyperesthetic, or pruritic.
Keloid
Histopathology: composed of thick, haphazard, eosinophilic, collagen bundles.
Keloid
Histopathology: more cellular with myofibroblasts either in disorganized whorls or sometimes oriented parallel to the epidermis
Hypertrophic scar
Associated Genetic syndrome: Keloids
Rubinstein–Taybi
Goeminne
Associated Genetic syndrome: Acrochordon-like lesions
Birt–Hogg–Dubé
Gorlin (Nevoid basal cell carcinoma)
Associated Genetic syndrome: Fibrous papules/angioma
Tuberous sclerosis
Multiple endocrine neoplasia type I
Birt–Hogg–Dubé
Associated Genetic syndrome: Fibrofolliculomas/ trichodiscomas
Birt–Hogg–Dubé