2: Pathology of the Skin Flashcards
What are the types of biopsies used in dermatology?
- Shave Biopsy: For epidermis or superficial dermis; used for non-melanoma skin cancer, seborrheic keratosis, actinic keratosis, verruca vulgaris, and some melanocytic nevi.
- Punch Biopsy: Best for most inflammatory dermatoses.
- Excisional Biopsy: For complete removal of a cutaneous neoplasm, including panniculitis and fasciitis.
- Curettage: Restricted to lesions with known diagnosis due to fragmented tissue evaluation; used for seborrheic keratosis, verruca, or BCC.
What factors should be considered when choosing the site for a biopsy?
- Choose lesions that have not been treated, excoriated, or secondarily infected.
- Select fully evolved lesions except in cases of blistering lesions.
- In blistering lesions, include edge and surrounding skin.
- In vasculitis and connective tissue diseases, avoid very early or old lesions.
- For unusual or persistent dermatoses or suspected CTCL, biopsy more than one lesion.
- In alopecia, perform two 4mm punch biopsies (horizontal and vertical sections) or use HoVert & Tyler technique.
What is the recommended submission process for skin biopsies?
- All routine skin biopsies should be submitted in 10% neutral buffered formalin.
- Ensure adequate formalin (10x the volume of the specimen).
- In cold weather, add 95% ethyl alcohol to the formalin to prevent freezing (must be 10% of the formalin volume).
- For autoimmune blistering diseases, DLE, and vasculitis, a separate piece of skin should be submitted in Michel Medium (containing ammonium sulfate, N-ethyl maleimide, and magnesium sulfate in citrate buffer).
- Include age, sex, anatomical location of biopsy, and clinical description or diagnosis.
What are the key considerations in the assessment of histopathology in dermatology?
- Use commonly employed immunohistochemical and histochemical stains to aid in diagnosis.
- Ensure that the histopathological evaluation includes a thorough review of the clinical context and any relevant patient history.
- If results are inconclusive, consider additional sampling or discussion with the pathologist for clarification.
What biopsy site should be chosen for a blistering lesion, and why?
For blistering lesions, include the edge and surrounding skin to capture the full pathology. This ensures the lesion’s progression and surrounding tissue are adequately assessed.
What special submission protocol should be followed for a biopsy in suspected autoimmune blistering disease?
Submit a separate piece of skin in Michel Medium (ammonium sulfate, N-ethyl maleimide, and magnesium sulfate in citrate buffer) for direct immunofluorescence (DIF) testing.
How many lesions should be biopsied in suspected cutaneous T-cell lymphoma (CTCL) and why?
Biopsy more than one lesion to ensure adequate sampling and accurate diagnosis.
What is the best biopsy type for inflammatory dermatoses, and why?
Punch biopsy is best for most inflammatory dermatoses as it provides a full-thickness sample of the skin.
What biopsy technique should be used for a patient with alopecia?
Perform two 4mm punch biopsies (horizontal and vertical sections) or use the HoVert & Tyler technique.
What factors should be considered before performing a biopsy in dermatology?
Before a biopsy, one must review:
1. Differential diagnosis
2. Anatomical location
3. Cosmetic result
What are the indications for using a shave biopsy in dermatology?
A shave biopsy is indicated if pathology is in the:
- Epidermis
- Superficial dermis
Common conditions include:
- Non-melanoma skin cancer
- Seborrheic keratosis
- Actinic keratosis
- Verruca vulgaris
- Some melanocytic nevi
What is the purpose of an excisional biopsy in dermatology?
An excisional biopsy is performed for the complete removal of a cutaneous neoplasm, including conditions like panniculitis and fasciitis.
What are the key considerations when choosing the site for a biopsy?
When choosing the site for a biopsy, consider the following:
- Best to choose lesions that have not been treated, excoriated, or secondarily infected.
- Choose fully evolved lesions EXCEPT in blistering lesions.
- In blistering lesions, include edge & surrounding skin.
What is the recommended submission method for skin biopsies?
All routine skin biopsies should be submitted in 10% neutral buffered formalin. Ensure adequate formalin (10x the volume of the specimen) is used. In cold weather, add 95% ethyl alcohol to prevent freezing (must be 10% of the formalin volume).
What additional information must be included when submitting a biopsy?
When submitting a biopsy, include:
- Age
- Sex
- Anatomical location of biopsy
- Clinical description or diagnosis
What is the significance of Direct Immunofluorescence (DIF) in skin biopsies?
DIF may be of benefit in autoimmune blistering diseases, DLE, and vasculitis. A separate piece of skin should be submitted in Michel Medium (containing ammonium sulfate, N-ethyl maleimide, and magnesium sulfate in citrate buffer).
What should be done if the biopsy result does not make sense?
If the biopsy result does not make sense, one should consider:
1. Additional sampling
2. Discussion with the pathologist
What are the common conditions that can be diagnosed using a punch biopsy?
Common conditions diagnosed using a punch biopsy include:
- Inflammatory dermatoses
- Seborrheic keratosis
- Verruca vulgaris
- Basal cell carcinoma (BCC)
What is dyskeratosis and what are its clinical implications?
Dyskeratosis refers to altered keratinization of individual keratinocytes or apoptosis of keratinocytes. It is characterized by:
- Eosinophilic cytoplasm and pyknotic nucleus packed with keratin filaments.
- Associated with conditions such as Darier disease, actinic keratosis (AK), squamous cell carcinoma (SCC), and can result from cytotoxic treatment and direct physical or chemical injuries.
- Sunburn cells are a type of eosinophilic apoptotic cells seen in sunburn.
- Individual cell death can occur in conditions like graft-versus-host disease (GVHD) and erythema multiforme (EM).
What are the characteristics and clinical significance of acanthosis?
Acanthosis is characterized by:
- Thickening of the epidermis due to enhanced cell proliferation.
- Enlargement of the germinative cell pool and increased mitotic rates.
Clinical significance: Acanthosis can indicate various skin disorders and is often associated with conditions such as psoriasis and diabetes mellitus. It reflects an imbalance in the normal processes of skin renewal and can lead to further complications if not addressed.
What is parakeratosis and what conditions can it result from?
Parakeratosis is defined as accelerated cornification leading to the retention of pyknotic nuclei at the epidermal surface. It can result from:
- Incomplete differentiation, often seen in squamous cell carcinoma (SCC).
- Reduced transit time, commonly associated with psoriasis.
Clinical significance: Parakeratosis indicates a disruption in normal keratinization processes and can be a marker for underlying skin pathologies.
What is spongiosis and how does it affect the epidermis?
Spongiosis is characterized by:
- Secondary loss of cohesion between epidermal cells.
- Caused by the influx of tissue fluid into the epidermis, leading to a stellate appearance or sponge-like morphology.
- Epidermal cells remain in contact at the sites of desmosomes, which can lead to the accumulation of PMN leukocytes in the epidermis, resulting in the formation of pustules.
Clinical significance: Spongiosis is often seen in inflammatory skin conditions such as eczema and can indicate an ongoing inflammatory process.
What is the significance of acantholysis in skin pathology?
Acantholysis refers to the primary loss of cohesion of epidermal cells, characterized by:
- Widening and separation of interdesmosomal regions of the cell membranes of keratinocytes.
- Cells round up, leading to intercellular gaps and influx of fluid, resulting in cavities in the suprabasal/mid-epidermal or subcorneum layers.
Clinical significance: Acantholysis is associated with conditions such as pemphigus, staphylococcal scalded skin syndrome (SSSS), and familial benign pemphigus, indicating severe disruption of epidermal integrity and potential for blister formation.
What are the implications of atrophy in the epidermis?
Atrophy in the epidermis is characterized by:
- Thinning of the epidermis
- Decreased epidermal proliferative capacity
- Initial loss of epidermal rete ridges, followed by progressive thinning of the epidermal layer.
Implications include increased vulnerability of the skin, potential for easier injury, and impaired barrier function.