2.5.2 Skin Pathology II Flashcards
What is this an image of?
What are the characteristics of Lupus Erythematous?
What is this an image of?
Pautrier microabcesses
Mycosis Fungoides
What are the characteristics of a skin tag?
Pedunculated papilloma
Appear on the neck, eyelid, trunk, groin, and axillae
Can be related to weight gain, pregnancy and diabetes
What are the characteristics of Lichen Planus?
Pruritic (itchy), purple, polygonal papules
Symmetric distribution favoring extremities, mucosa
1% population
30-60 years old
Exposure to virus (hepatitis C), medication, contact allergen leads to altered self-antigens on basal keratinocytes
T-cells induce death via apoptosis of basal keratinocytes
What are characteristics of dermatofibrosarcoma protuberans?
Bulky irregular tumor
Usually appears on the trunk
Middle-aged adults
Locally aggressive
What is this an image of?
What are the covered parts in this image?
What is this an image of?
Ichthyosis vulgaris
Ichthyosis vulgaris is the most common hereditary ichthyosis. It has an incidence of 1 in 250. It manifests with brownish scales with a predilection for the extensor skin of the extremities and is frequently associated with keratosis pilaris and atopic dermatitis. Some cases are rather mild, and the distinction between dry skin and mild ichthysosis vulgaris may be subjective. By biopsy, ichthyosis is one of the famous “nil” differential of normal skin. Your eye is trained to recognize positive differences – a proliferation of melanocytes, an inflammatory infiltrate, separation between the epidermis and dermis. We are not so good at recognizing negative differences – differences of subtraction rather than addition. In the case of ichthyosis vulgaris, what isn’t present is key to the diagnosis. This biopsy looks much like normal skin. What’s missing? (box) The granular layer. Careful examination of the interface between viable skin and the cornified layer will reveal a diminished granular layer in most patients. However, there are usually at least a few poorly-formed keratohyaline granules in most patients.The stratum corneum is significantly thicker than the viable epidermis, indicating a disorder of cornification. In normal skin, as there is a corresponding increase in the thickness of the granular layer for increases in orthokeratosis. Patients with ichthyosis vulgaris have a defect in the filaggrin gene resulting in diminished amounts of profilaggrin, a key constituent of the granular layer. This makes the corneocytes of the stratum corneum more tightly adherent to one another than normal, and produces visible scales.
The differential includes dry skin, or xerosis, which produces a mild spongiotic dermatitis with parakeratosis. Steroid sulfatase deficiency, or X-linked ichthyosis, produces similar scales but is restricted to male patients. It almost always involves the neck, which is often spared in ichthyosis vulgaris; biopsy demonstrates a preserved granular layer in steroid sulfatase deficiency.
What are the characteristics of a dermatofibroma?
Red-brown firm nodule
Dimple-Sign
Lower extremities
Middle aged adults
How does the image on the left compare to the image on the right?
Left - Ichthyosis Vulgaris
Right - Normal
What is this an image of?
Chronic Eczema
This is an example of a chronic eczema in a patient with an atopic predisposition. Chronic eczema demonstrates prominent psoriasiform epidermal hyperplasia with thickening of the granular layer, scale, fibrovascular expansion of the papillary dermis and a superficial dermatitis often with some eosinophils. In some patients, the epidermal changes are associated with relatively sparse inflammation suggesting the clinical changes are primarily due to the patient’s scratching and rubbing rather than a persistent hypersensitivity reaction.
What are the characteristics of Mycosis Fungoides?
Malignant memory T-helper cell (CD4+)
Favors sun protected sites
5+ cm patches and thin plaques
Erythrodema, tumors = bad
What are the covered parts of this image?
What is this an image of?
What is this an image of and what are the arrows pointing at?
Skin tag
Top - Outer layer - kertinizing squamous epithelium
Bottom - inner fibrovascular core NO adnexa
What are the covered parts of this image?
What are the characteristics of Oculo-cutaneous albinism?
Diffuse hypopigmentation
1/20,000 births
Autosomal Recessive
Defect in melanin synthesis
eye problems
What are the covered parts of this image?
What is this an image of and what are the covered parts?
Epidermoid cyst
Loose Keratin and Granular layer
Epidermoid cysts are the most common cyst seen in pathology. They are also called epidermal inclusion, infundibular and sebaceous cysts. I prefer the term epidermoid cyst because they are of follicular origin rather than epidermal or sebaceous origin, but they are lined by an epithelium that mimics the epidermis (box). Oid means “like.” they have a predilection for the face and upper trunk. Mulitple epidermoid cysts are seen in familial adenomatous polyposis (Gardner syndrome) and basal cell nevus syndrome. They are lined by keratinizing squamous epithelium with a granular layer. The lining can be differentiated from bona fide epidermis by the lack of adnexa or rete ridges. Often the surrounding stroma is scar-like. Sometimes only the cyst contents are submitted to pathology. You can still make a reasonably sure diagnosis of epidermoid cyst if the contents consist of abundant flaky laminated keratin. An important differential diagnosis is with the confusingly named “dermoid” cyst (box). Dermoid cysts are congenital lesions located on the orbital ridge. Histologic sections demonstrate stratified squamous epithelium like that of epidermoid cysts, but there are also adnexal structure such as sebaceous glands (arrow) and hair follicles (arrow)
What is this an image of?
Lichen Planus
What is this an image of?
Pilar Cyst
Compact Keratin and NO granular layer
90% of pilar cysts are often located on the scalp, though they can be found anywhere on hair-bearing skin. They are often multiple and may be inherited. They are also called tricholemmal and isthmus-catagen cysts. They contain dense pink, compact keratin that is often calcified and may include cholesterol crystal. They tend to shell out during incsion, and they are usually submitted intact. Submission of cyst contents alone is not uncommon in epidermoid cysts but very rare in pilar cysts. They are lined by stratified squamous epithelium without a granular layer (box). Unlike epidermoid cysts in which the lining cells become progressively flatter towards the inner aspect of the cyst, those in pilar cysts appear to enlarge as they approach the keratinous cyst contents.
What is this an image of?
Mastocytosis
What is the metabolic error in oculo-cutaneous albinism?
Defect in Tyrosinse
What are these two images of?
Left - CD1a marker
Right - Birbeck granule
Parts of Langerhans cells
What is this an image of?
Dermatofibroma
What is this an image of?
Mycosis Fungoides
What is this an image of?
Ichthyosis vulgaris
What are the two important genetic skin diseases?
Ichthyosis vulgaris
Oculocutaneous albinism
What is this an image of?
Mastocytosis
Fried egg appearance
What are the characteristics of Ichthyosis vulgaris?
Fine scales
Lower extremities in particular
Autosomal dominant
Deficiency in profilaggrin
Autosomal dominant deficiency in profillagrin causes abnormal retention of corneocytes.
What are the characteristics of Atopic (Eczematous) Dermatitis?
Pruritic, erythematous, oozing rash with vesicles and edema; often involves the face and flexor surfaces
Type 1 hypersensitivity reaction - associated with asthma and allergic rhinitis
What are the characteristics of allergic contact Eczema?
Pruritic, erythematous, oozing rash with vesicles and edema
Arises upon exposure to allergens
What are the classical histological features of Mycosis Fungoides?
Pautrier microabcesses
What are the characteristics of Mastocytosis?
Localized increase in Mast Cells
Brown oval plaques Darier Sign
Urticaria Pigmentosa
What is this an image of?
Mycosis Fungoides
Neoplastic T-cells in lower epidermis
