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.
How does the disturbance of epidermal cell cohesion manifest in skin lesions?
Disturbance of epidermal cell cohesion manifests as:
- Intraepidermal vesicles, which are common results of disrupted cohesion.
- Loss of intercellular attachment devices (desmosomes) leading to skin fragility.
- Clinical presentations may include blistering and increased susceptibility to skin infections.
What role do basal cells play in the epidermis?
Basal cells in the epidermis play a crucial role by:
- Undergoing proliferation cycles for the renewal of the epidermis.
- Maintaining the balance between keratinization, cell death, and sloughing, ensuring continuous replenishment of the skin’s outer layer.
What is the clinical significance of sunburn cells in the context of dyskeratosis?
Sunburn cells are eosinophilic apoptotic cells that appear in the epidermis following UV exposure. Their presence indicates:
- Dyskeratosis due to keratinocyte apoptosis.
- Potential for long-term skin damage, including increased risk of skin cancers such as squamous cell carcinoma (SCC).
- A marker for assessing the extent of sun damage and the skin’s response to injury.
What is the role of hemidesmosomes in the dermal-epidermal junction?
Hemidesmosomes anchor basal cells to the basal lamina, which is attached to the dermis by anchoring filaments and microfibrils.
What are the characteristics of the basal lamina in the dermal-epidermal junction?
The basal lamina is reconstituted after being destroyed, periodic acid-Schiff positive, represents the entire junction zone, and consists of the lamina lucida, microfilaments, anchoring fibrils, small collagen fibers, and extracellular matrix.
What is the primary target in junctional blistering?
In junctional blistering, the target is the cytomembrane of basal cells.
What are the pathologic events associated with psoriasis?
- Perivascular accumulation of lymphocytes within the papillary dermis (initial event)
- Focal migration of leukocytes into the epidermis (initial event)
- Acanthosis
- Elongation of rete ridges (papillomatosis)
- Edema of the elongated dermal papillae
- Vasodilatation of the capillary loops.
What are the differences between interface and lichenoid dermatitis?
Interface
- Sparse lymphocyte infiltrate along the DEJ with vacuolar alteration of basal layer keratinocytes
Lichenoid
- Dense, band-like lymphocyte infiltrate at the dermal-epidermal junction with dyskeratosis, hyperkeratosis, and hypergranulosis.
What is spongiotic dermatitis and its clinical significance?
Spongiotic dermatitis is an inflammatory reaction of the papillary dermis.
What are the differences between interface and lichenoid dermatitis?
Interface dermatitis has sparse lymphocyte infiltrate along the DEJ with vacuolar alteration of basal layer keratinocytes, while lichenoid dermatitis has dense, band-like lymphocyte infiltrate at the DEJ with dyskeratosis, hyperkeratosis, and hypergranulosis.
What is spongiotic dermatitis and its clinical significance?
Spongiotic dermatitis is an inflammatory reaction of the papillary dermis and superficial microvascular plexus, leading to spongiosis of the epidermis. It is characterized by lymphocyte infiltration around Langerhans cells, resulting in acanthosis and hyperkeratosis in chronic lesions.
What histological features would you expect in spongiotic dermatitis?
Spongiotic dermatitis shows inflammatory reaction in the papillary dermis, spongiosis of the epidermis, lymphocyte infiltration, spongiotic vesiculation, parakeratosis, acanthosis, and hyperkeratosis in chronic lesions.
A patient presents with psoriasis. What are the key pathological events in this condition?
Key events include perivascular lymphocyte accumulation, leukocyte migration into the epidermis, acanthosis, elongation of rete ridges, edema of dermal papillae, vasodilation of capillary loops, parakeratosis, and Munro microabscesses.
What is the role of hemidesmosomes in the dermal-epidermal junction?
Hemidesmosomes anchor basal cells onto the basal lamina, which is attached to the dermis by anchoring filaments and microfibrils.
What are the pathologic events associated with psoriasis?
- Perivascular accumulation of lymphocytes within the papillary dermis (initial event)
- Focal migration of leukocytes into the epidermis (initial event)
- Acanthosis
- Elongation of rete ridges (papillomatosis)
- Edema of the elongated dermal papillae
- Vasodilatation of the capillary loops
What is the clinical significance of parakeratosis in spongiotic dermatitis?
Parakeratosis develops as a consequence of epidermal injury and proliferative responses, leading to acanthosis and hyperkeratosis in chronic lesions.
What are the implications of dermolytic blistering in skin pathology?
Dermolytic blistering targets structures below the basal lamina, leading to conditions such as recessive epidermolysis bullosa and acquired epidermolysis bullosa.
What are the histological features of bullous pemphigoid?
Bullous pemphigoid is characterized by the presence of autoantibodies against hemidesmosomes, leading to blister formation at the dermal-epidermal junction.
What is the significance of Munro microabscesses in psoriasis?
Munro microabscesses are small aggregates of neutrophils infiltrating the upper epidermis in psoriasis, indicating disturbed differentiation of epidermal cells and contributing to parakeratosis.
What are the characteristics of the epidermis in conditions like lichen planus and lupus erythematosus?
The epidermis may be thickened in lichen planus or atrophic in lupus erythematosus. Additionally, interface/lichenoid changes can be observed in conditions such as dermatomyositis, erythema multiforme, secondary syphilis, fixed drug reactions, graft-versus-host disease, and lichenoid drug reactions.
What is the significance of eosinophils and neutrophils in subepidermal blistering processes?
In subepidermal blistering processes:
1. Eosinophils align at the dermal-epidermal junction (DEJ) in conditions like bullous pemphigoid.
2. Neutrophils are present at the DEJ in conditions such as dermatitis herpetiformis, linear immunoglobulin A disease, bullous lupus erythematosus, and inflammatory epidermolysis bullosa acquisita.
3. In some cases, there may be little to no inflammatory cells, as seen in porphyria cutanea tarda and the cell-poor variant of pemphigoid.
What are the two reaction patterns observed in the angiocentric pattern of skin lesions?
In the angiocentric pattern, two reaction patterns are observed:
1. Acute inflammatory processes where the epidermis and junctional zone are often involved along with the vascular system.
2. Chronic processes that typically remain confined to the perivascular compartment.
What types of inflammatory processes are associated with the periadenxal pattern?
The periadenxal pattern involves inflammatory processes around skin adnexal structures, which include:
- Acneiform processes
- Infectious folliculitis (caused by bacteria, fungus, or herpesvirus)
What distinguishes the nodular/diffuse pattern from the angiocentric pattern in skin lesions?
The nodular/diffuse pattern is characterized by larger aggregates compared to the angiocentric pattern. It includes nodular collections of lymphocytes such as cutaneous B-cell lymphoma and cutaneous lymphoid hyperplasia, as well as nodular collections of neutrophils such as Sweet syndrome and pyoderma gangrenosum.
What histological features would help you identify bullous pemphigoid?
Eosinophils align at the dermo-epidermal junction (DEJ) in bullous pemphigoid.
What histological pattern is seen in Sweet syndrome?
Sweet syndrome shows nodular collections of neutrophils.
What is the significance of studying the edge of a blister in subepidermal blistering processes?
Studying the edge of the blister helps in evaluating the character of the inflammatory cells present. For example, eosinophils align at the dermal-epidermal junction in bullous pemphigoid, while neutrophils are seen in dermatitis herpetiformis and other conditions.
What are the characteristics of lymphocytes in skin infiltrates?
Small round/oval nuclei and very little cytoplasm. Lymphocytic cuffing of venules without involvement of the papillary dermis and epidermis is seen in figurate erythemas, viral exanthema, drug eruptions, and chronic lymphocytic leukemia.
What are the key features of eosinophils in skin infiltrates?
Eosinophils are recognized by their characteristic bilobed nucleus and eosinophilic granular cytoplasm. Many eosinophils in a dermal infiltrate are associated with allergic reactions, Wells syndrome, angiolymphoid hyperplasia with eosinophilia, and the prodromal stage of pemphigoid.
What is the significance of neutrophils in skin lesions?
Neutrophils have multilobed nuclei and a less eosinophilic cytoplasm than eosinophils. Neutrophil-rich infiltrates often imply an infectious etiology but can also be associated with noninfectious neutrophilic processes in the skin.
What defines a granulomatous reaction in skin pathology?
Granuloma is characterized by the proliferation and focal aggregation of histiocytic cells. Granulomas usually lead to destruction of elastic fibers, resulting in atrophy, fibrosis, and scarring.
What types of granulomas are associated with infectious processes?
Infectious granulomas with a sarcoidal appearance can be seen in tuberculosis, syphilis, leishmaniasis, leprosy, and atypical mycobacterial or fungal infections.
What histological features are seen in granuloma annulare?
Granuloma annulare shows palisading granulomas surrounding hypocellular connective tissue areas with histiocytes in radial alignment.
What distinguishes sarcoidal granulomas from infectious granulomas?
Sarcoidal granulomas lack necrosis, while infectious granulomas may show fibrinoid necrosis, caseation, or necrosis in the granuloma proper.
What are the characteristics of lymphocytic infiltrates in skin lesions?
Characteristics of Lymphocytic Infiltrates: Small round/oval nuclei with very little cytoplasm.
What conditions are associated with lymphocytic infiltrates in skin lesions?
Conditions Associated: Lymphocytic cuffing of venules without involvement of the papillary dermis and epidermis seen in figurate erythemas, viral exanthema, drug eruptions, and chronic lymphocytic leukemia; perivascular lymphocytic infiltrates with mucinous infiltration seen in lupus erythematosus and dermatomyositis; nodular lymphocytic infiltrates mimicking lymph node tissue seen in lymphocytoma cutis and cutaneous lymphoid hyperplasia; atypical lymphocytic infiltrates characterized by pronounced pleomorphism seen in lymphomatoid papulosis.
What are the roles and characteristics of eosinophils in skin lesions?
Roles and Characteristics of Eosinophils: Recognized by their bilobed nucleus and eosinophilic granular cytoplasm. Associated with allergic reactions, Wells syndrome, angiolymphoid hyperplasia with eosinophilia, and the prodromal stage of pemphigoid.
What are the features of neutrophilic infiltrates in skin lesions?
Features of Neutrophilic Infiltrates: Neutrophils have multilobed nuclei and a less eosinophilic cytoplasm than eosinophils.
What conditions can neutrophilic infiltrates indicate?
Conditions Indicated by Neutrophilic Infiltrates: Often imply an infectious etiology, but can also be associated with noninfectious processes such as Sweet syndrome, pyoderma gangrenosum, and urticarial vasculitis.
What is a granuloma?
Granuloma: A proliferation and focal aggregation of histiocytic cells.
What are the key features associated with granulomatous reactions in skin lesions?
Key Features of Granulomatous Reactions: Closely clustered histiocytic cells resemble epithelial tissue, granulomas can lead to destruction of elastic fibers, and tissue damage may manifest as necrobiosis, fibrinoid or caseous necrosis, liquefaction and abscess formation, and replacement of preexisting tissue by fibrohistiocytic infiltrate and fibrosis.
What types of granulomas are associated with specific infectious diseases?
Infectious Granulomas Associated with Specific Diseases: Tuberculosis, syphilis, leishmaniasis, leprosy, atypical mycobacterial or fungal infections.
What are the types of non-infectious granulomas and their characteristics?
Types of Non-Infectious Granulomas: Sarcoidal granulomas, foreign-body granulomas, palisading granulomas. Examples of Conditions: Granuloma annulare, necrobiosis lipoidica, rheumatoid nodules.
What is the significance of necrosis in granulomatous reactions?
Significance of Necrosis in Granulomatous Reactions: Necrosis can develop within the granuloma proper, indicating tissue damage.
What types of necrosis can occur in granulomatous reactions?
Types of Necrosis: Fibrinoid necrosis in sarcoidosis, caseation necrosis in tuberculosis, necrosis in mycotic granulomas.
What are xanthomatous reaction patterns?
Xanthomatous Reaction Patterns: Histiocytes take up and store fat, transforming into foam cells.
What conditions are associated with xanthomatous reactions?
Conditions Associated with Xanthomatous Reactions: Tuberous xanthoma, eruptive xanthomas, xanthelasma.
What are the hallmark features of scleroderma and morphea?
The hallmark features include homogenization, thickening, and dense packing of the collagen bundles; narrowing of the interfascicular clefts within the reticular dermis; perivascular infiltrate of lymphocytes and plasma cells.
What are the histopathologic changes associated with Ehlers-Danlos syndrome?
Ehlers-Danlos syndrome is characterized by an increase in elastic tissue within the dermis.
What is lobular panniculitis?
Lobular panniculitis is an inflammatory process of the fat lobules, involving lipid material derived from damaged adipocytes.
What factors are used to assess the benignancy versus malignancy of skin tumors?
The factors to assess skin tumors include symmetry, pattern of infiltration, cytology, and mitotic activity.
What are the characteristics of benign tumors compared to malignant tumors?
Benign Tumors: Good symmetry, well-circumscribed, smaller bland-appearing & uniform nuclei, less frequent mitotic figures. Malignant Tumors: More infiltrative pattern, larger nuclei, nuclear pleomorphism & prominent nucleoli, more frequent mitotic figures, atypical mitotic figures.
What are the key features of verruca vulgaris?
Verruca vulgaris is characterized by marked hyperkeratosis, papillomatosis, and acanthosis; presence of koilocytic changes including small round nuclei, perinuclear halos, and clumping of keratohyaline granules.
What type of panniculitis is erythema nodosum?
Erythema nodosum is a septal panniculitis characterized by edema, inflammatory cell infiltration, and a histiocytic reaction in the septa.
What is the significance of Verhoeff-van Gieson staining in skin pathology?
Verhoeff-van Gieson staining is used to highlight the presence, absence, or alteration of elastic fibers in the dermis.
What are the differences between lobular and septal panniculitis?
Lobular panniculitis involves inflammation of the fat lobules due to lipid material from damaged adipocytes, while septal panniculitis arises in the septum and is characterized by conditions like erythema nodosum.
The superficial reaction unit comprises what layers of the skin?
Epidermis
Junctional zone
Papillary body with its vascular system
The second reactive unit comprises what layers of the skin?
Reticular dermis
Deeper dermal vascular plexus
The third reactive unit comprises what layers of the skin?
Subcutaneous tissue with its septal and lobular compartments
The fourth reactive unit comprises what layers of the skin?
Hair follicles and glands.
Biopsy type for suspected AK?
Shave.
Biopsy type for suspected SK?
Shave.
Biopsy type for suspected verruca?
Shave.
Biopsy type for suspected BCC?
Shave (most common); punch/excision.
Biopsy type for suspected SCC?
Shave (most common); punch/excision.
Biopsy type for suspected blistering disease?
Punch or deep shave edge of blister.
Biopsy type for suspected contact dermatitis?
Punch.
Biopsy type for suspected connective tissue disease?
Punch.
Biopsy type for suspected MF?
Punch.
Biopsy type for suspected vasculitis?
Punch.
Biopsy type for suspected granulomatous process?
Punch.
Biopsy type for suspected atypical nevi?
Deep shave, punch, excision.
Biopsy type for suspected panniculitis?
Punch (minimum 6 mm) or ellipse.
What IHC stains are EPITHELIAL markers and what are their associated conditions?
What IHC stains are MESENCHYMAL markers and what are their associated conditions?
What IHC stains are NEUROECTODERMAL markers and what are their associated conditions?
What IHC stains are HEMATOPOIETIC markers and what are their associated conditions?
What IHC stain is an INFECTIOUS marker and what is its associated conditions?
Condition/s associated with (+) P63?
Cutaneous spindle cell SCC
Condition/s associated with (+) CAM5.2?
PD, EMPD
Condition/s associated with (+) CK7?
PD, EMPD
Condition/s associated with (+) CK20?
MCC
Condition/s associated with (+) EMA?
SCC
Condition/s associated with (+) CEA?
Sweat gland neoplasms, PD, EMPD
Condition/s associated with (+) Desmin?
Skeletal and smooth muscle tumors (leiomyoma)
Condition/s associated with (+) SMA?
Glomus tumor
Leiomyosarcoma
Condition/s associated with (+) CD34?
DFSP
Trichoepithelioma
Condition/s associated with (+) Factor XIIIa?
Dermatofibroma
Condition/s associated with (+) CD31?
Vascular tumors
Condition/s associated with (+) D2-40 / podoplanin?
Lymphatic endothelial conditions
Condition/s associated with (+) GLUT1?
Infantile hemangiomas
Condition/s associated with (+) Vimentin?
Sarcoma
Condition/s associated with (+) S100?
Desmoplastic melanoma
LCH
Granular cell tumor
Condition/s associated with (+) HMB-45?
Desmoplastic melanoma
Blue nevus
Condition/s associated with (+) Melan-A, Mart-1?
Desmoplastic melanoma
Condition/s associated with (+) CD45Ra (LCA)?
Hematolymphoid proliferations
Condition/s associated with (+) CD20?
B-cell lymphomas
Condition/s associated with (+) CD10 (CALLA)?
Atypical fibroxanthomas
Clear cell hidradenoma
Sebaceous tumors
Condition/s associated with (+) CD79a?
Plasma cell, B-cell marker
Condition/s associated with (+) CD138 (syndecan-1)?
Plasma cell marker
Condition/s associated with (+) CD3?
T cell lymphomas
Relevance of CD4?
T-helper lymphocytic marker
Condition/s associated with (+) CD5?
Mantle cell lymphoma
Chronic lymphocytic leukemia
Relevance of CD7?
Most commonly lost antigen in T-cell lymphoma?
Relevance of CD8?
T cell cytotoxic / suppressor marker
Condition/s associated with (+) CD30?
Anaplastic large cell lymphoma
Lymphomatoid papulosis
Chronic arthropod bites (scabies, tick)
Relevance of Langerin / CD207?
Langerhans cell identification
Condition/s associated with (+) CD1a?
LCH
Condition/s associated with (+) BCL2?
B-cell lymphoproliferative disorders
Condition/s associated with (+) HHV8?
Kaposi sarcoma
What histochemical stain?
Verhoeff-Van Gieson
What histochemical stain?
Toluidine blue
What histochemical stain?
Masson’s trichrome
What histochemical stain?
Leder stain
What histochemical stain?
Periodic acid-Schiff
What 2 histochemical stains?
Alcian blue
Colloidal iron
What histochemical stain?
Mucicarmine
What 3 histochemical stains stain amyloid and how do they differ?
What histochemical stain?
Prussian blue (Perls stain)
What histochemical stain?
Fontana-Masson
What 2 histochemical stains stain calcium and how do they differ?
What 2 histochemical stains stain lipid and how do they differ?
What histochemical stain?
Gomori methenamine silver
What 2 histochemical stains stain mycobacteria and how do they differ?
What histochemical stain?
Warthin-starry
Giemsa stain is used to highlight what cells?
MMLH:
Conditions in which the anatomic level of split is in the GRANULAR layer?
Conditions in which the anatomic level of split is in the SPINOUS layer?
Conditions in which the anatomic level of split is in the SUPRABASAL layer?
Conditions in which the anatomic level of split is in the SUBEPIDERMAL layer?
In choosing the site to biopsy, choose fully evolved lesions except in _____.
Blistering conditions.
In choosing the site to biopsy, avoid very early or old lesions in _____ and _____.
Vasculitis
Connective tissue disease
2 histopathologic features indicating a disturbance of epidermal cell kinetics?
Acanthosis
Atrophy
2 histopathologic features indicating a disturbance of epidermal cell differentiation?
Parakeratosis
Dyskeratosis
2 histopathologic features indicating a disturbance of epidermal cell cohesion?
Spongiosis
Acantholysis
_____ is the thinning of the epidermis. One primary etiology is a decrease in epidermal proliferative capacity as seen in aging and prolonged steroid use. Epidermal rete ridges are initially lost, followed by progressive thinning of the epidermal layer.
Atrophy
Enhanced cell proliferation accompanied by an enlargement of the germinative cell pool and increased mitotic rates lead to an increase of the epidermal cell
population and thus to a thickening of the epidermis, known as:
Acanthosis
It is described as the retention of pyknotic nuclei of cells at epidermal surfaces.
Parakeratosis
It is caused by altered keratinization of individual keratinocytes or apoptosis of keratinocytes.
Dyskeratosis
It is the secondary loss of cohesion between epidermal cells caused by
the influx of tissue fluid into the epidermis.
Spongiosis
It is the primary loss of cohesion of epidermal cells, widening &
separation of interdesmosomal regions of the cell membranes of keratinocyte.
Acantholysis
Type of blistering where the target is cytomembrane of basal cells.
Junctional
Type of blistering where the target is below the basal lamina.
Dermolytic
What are the pathologic reactions of the dermo-epidermal junction?
Junctional blistering
Dermolytic blistering
The most common result of disturbed epidermal cohesion?
Intraepidermal vesicle
What are pathologic reactions of the entire superficial reactive unit?
Spongiotic dermatitis
Psoriasis
Interface and lichenoid dermatitis
subepidermal blistering processes
Describe the histopathology of spongiotic dermatitis.
● (+) Inflammatory reaction of the papillary dermis and superficial microvascular plexus and spongiosis of the epidermis.
● Parakeratosis
● Inflammation results in acanthosis and hyperkeratosis in chronic lesions.
Describe the histopathology of psoriasis.
● Perivascular accumulation of lymphocytes within the papillary dermis
● Focal migration of leukocytes into the epidermis
● Acanthosis
● Elongation of rete ridges (papillomatosis)
● Edema of the elongated dermal papillae
● Vasodilatation of the capillary loops
● small aggregates of neutrophils infiltrating the upper epidermis (spongiform
pustules)
● parakeratotic stratum corneum (Munro microabscesses)
Describe the histopathology of interface and lichenoid dermatitis and how they differ.
Lymphocytes are present along the DEJ associated with vacuolar alteration of basal layer keratinocytes.
Interface
● infiltrate is sparse
Lichenoid
● infiltrate is dense and band-like at the dermal–epidermal junction
● Epidermis may be thickened (lichen planus) or atrophic (lupus erythematosus)
What are the dominant inflammatory cells involved in different subepidermal blistering processes?
○Eosinophils align at DEJ - bullous pemphigoid.
○ Neutrophils at DEJ - Dermatitis herpetiformis, linear immunoglobulin A disease, bullous lupus erythematosus, and inflammatory epidermolysis bullosa acquisita.
○ little to no inflammatory cells - porphyria cutanea tarda, epidermolysis bullosa acquisita, or the cell-poor variant of pemphigoid.
What are the different pattens of inflammatory cell infiltrate?
Angiocentric / perivascular
Periadnexal
Nodular / diffuse
DDx of nodular collections of lymphocytes?
○ Cutaneous B-cell lymphoma
○ Cutaneous lymphoid hyperplasia (pseudolymphoma)
○ Angiolymphoid hyperplasia
**immunohistochemical staining for various T-cell and B-cell antigens is
helpful to establish diagnosis
DDx of nodular collections of neutrophils?
○ Sweet syndrome
○ Pyoderma gangrenosum
○ Follicular rupture
○ Abscess formation associated with infection
