📚 Question Bank

The above image shows nucleated stratum corneum suggestive of parakeratosis commonly seen in psoriasis and actinic keratosis.

Parakeratosis refers to abnormal keratinization in which the cells of basal layer divide rapidly reaching the stratum corneum faster and do not have time to shed the nucleus. As a result, the nucleated stratum corneum is observed on histopathology.

Hyperkeratosis refers to the increased thickness of the stratum corneum. This is observed in psoriasis, lichen planus, and ichthyosis.

The above image shows intercellular edema involving the stratum spinosum which is suggestive of spongiosis. Spongiosis is the characteristic histopathological feature of acute eczema.

In contrast, ballooning degeneration is a term that refers to the intracellular edema occurring in the stratum spinosum. This results in acantholysis. Ballooning degeneration is often seen secondary to viral infections like herpes.

The image below shows ballooning degeneration (intracellular edema is seen).

Microabscess is not typical of lichenoid tissue reactions. Skin changes in lichenoid tissue reactions:

• Upper dermis - Bandlike infiltrate of mononuclear cells.
• Dermoepidermal junction - Sawtoothed pattern.
• Basal cell layer - Liquefaction degeneration, colloid body formation.
• Epidermis - Increase in thickness.
• Lichenoid reactions are seen in:
• Lichen planus
• Lupus erythematosus
• Lichen sclerosis
• Poikilodermas
• Cutaneous drug eruptions.

The given scenario with symptoms of purple, itchy, plaque exhibiting Koebner's phenomenon is suggestive of lichen planus. It is characterized by the presence of Civatte bodies or colloid bodies as seen in the image above.

The colloid body is a homogeneous, eosinophilic, rounded body resulting from the degeneration and death of keratinocytes, particularly in the lower layers of the epidermis. This structure is found in various lichenoid tissue reactions.

Option A: Copper penny bodies are seen in chromoblastomycosis.

Option C: Donovan bodies are seen in granuloma inguinale.

Option D: Kamino bodies are eosinophilic globules seen in the epidermis or in the region of the dermal-epidermal junction in the spindle and epithelioid cell (Spitz) naevi.

Acantholysis is not seen in bullous pemphigoid as it is associated with subepidermal blistering.

Acantholysis is the loss of intercellular connections, such as desmosomes, resulting in the loss of cohesion between keratinocytes.

Acantholysis is classified as:

The image below shows acantholysis (note the rounded and free-floating, detached keratinocytes).

Primary

Ruptureof the desmosome fir st, forming circular acantholy tic cells

Seen in:Pemphigus vulgarisSt aphylococcal scalded skin syn dromeDarier's diseaseHailey Hailey disease

Secondary

Ballooningof the keratinocyte first, formingcircular acanth olytic cells(Tzank cell)

Seen in:Herpes simplex infec tions (HSV-1 and 2)Varicella- zosterinfections (chickenpox, shingles)

Acanthosis is characterized by the increase in the number of cells of the stratum spinosum leading to its increased thickness.

Acanthosis is commonly accompanied by other histological changes such as hypergranulosis, hyperkeratosis, and papillomatosis. It is seen in verruca vulgaris, chronic eczema, lupus vulgaris.

Kindly note that this should not be confused with the term acantholysis. Acantholysis refers to the loss of cohesion between keratinocytes due to the breakdown of intercellular bridges formed by desmosomes. This can be seen in various pemphigus-related disorders and secondary to bullous impetigo and other infections.

The image below shows acanthosis. Notice the increased thickness of the Malpighian layer and the elongated rete ridges.

The above image showing abnormal epidermal cell keratinization suggestive of dyskeratosis along with the clinical presentation points to a likely diagnosis of Bowen's disease.

Dyskeratosis is characterized by nuclear pyknosis and condensation of the cytoplasm of keratinocytes.

This can occur in:

• Malignant lesion - squamous cell carcinoma
• Premalignant lesions:
• Bowen disease
• Paget’s disease
• Solar keratosis
• Benign conditions:
• Darier disease
• Hailey Hailey disease

The above image shows upward elongation of the dermal papillae, giving an accentuated and sometimes irregular, undulating configuration to the dermal-epidermal junction which is suggestive of papillomatosis. The feature is commonly seen in psoriasis, and a wide variety of

other inflammatory and neoplastic cutaneous disorders.

Option B: Parakeratosis can be defined as the retention of keratinocyte nuclei within the stratum corneum. It is commonly seen in psoriasis.

Option C: Saw toothing refers to the pattern of the dermal-epidermal junction where dermal papillae are expanded and the tips of the rete pegs are pointed. It is seen in lichen planus and other lichenoid reactions.

Option D: Villi refers to elongated dermal papillae usually covered with a single layer of epidermal cells, which form the base of a blister cavity as a result of suprabasal acantholysis. It is seen in various forms of pemphigus and Darier disease.

Neutrophilic micro-abscesses are seen in psoriasis.

A microabscess is a small cavity in the epidermis or dermis formed by collections of leucocytes. Some types of microabscesses and their examples are given below:

Predominant cell

Neutrophilic microabsce ss

Lymphocytic microabsce ss

Eosinophilic microabsces s

Name of microabscess

Papillary tip microabscessMu nroe's microabscess (superfic ial)Spongiform pustules of K ogoj (deep)

Pautrier's microabscess

Disease

Dermatitis HerpetiformisPso riasis

Mycosis fungoides Pemphigus vegetans

In the given image, the arrow points to a small collection of cells seen within the stratum corneum in a patient with psoriasis. This is suggestive of a Munro's microabscess.

Munro's microabscesses are small collections of neutrophil polymorphs. Hyperkeratosis and parakeratosis are also seen here.

The spongiform pustule of Kogoj refers to the multilocular micropustules that form in the spinous layer of the epidermis in pustular psoriasis.

Predominant cell

Neutrophilic microabsce ss

Lymphocytic microabsce ss

Eosinophilic microabsces s

Name of microabscess

Papillary tip microabscessMu nroe's microabscess (superfic ial)Spongiform pustules of K ogoj (deep)

Pautrier's microabscess

Disease

Dermatitis HerpetiformisPso riasisPsoriasis

Mycosis fungoides Pemphigus vegetans

The arrow mark is pointing towards a collection of atypical lymphocytes in the epidermis termed as Pautrier microabscess. This is a very important histopathology feature of mycoses fungoides which is the most common type of cutaneous T cell lymphoma.

Predominant cell Neutrophilic microabscess

Lymphocytic microabsces s

Eosinophillic microabsces s

Name of microabscess

Papillary tip microabscessMu nroe's microabscess (superfic ial)Spongiform pustules of K ogoj (deep)

Pautrier's microabscess

Disease

Dermatitis HerpetiformisPso riasisPsoriasis

Mycosis fungoides Pemphigus vegetans

The above image shows malignant lymphocytes that have migrated to the epidermis from the dermis which is called epidermotropism. It is seen in mycosis fungoides.

Pautrier's microabscess constituting a collection of atypical T-cells in the epidermis is also a feature of mycosis fungoides (cutaneous T-cell lymphoma).

The image below shows atypical lymphocytes showing epidermotropism and the formation of Pautrier's microabscesses (Hamp;E stain, 4••x).

Purpura is a primary skin lesion. Crust, atrophy, and induration are secondary lesions.

It is a condition with red or purple discolored spots on the skin that do not blanch on applying pressure. The spots are caused by bleeding underneath the skin. It is seen:

• Vasculitis
• Thrombocytopenia
• Vitamin C deficiency

Option A: Crusts or scabs consist of dried-up discharge from the lesions.

Option B: Atrophy refers to loss of tissue. There may be fine wrinkling and increased translucency if the process is superficial.

Option D: Induration refers to dermal thickening that clinically presents as skin that feels thicker and firmer than normal on palpation.

Image 4 shows an ulcer with crusting. This is a secondary skin lesion.

Images 1, 2, and 3 show a bulla, a papule, and a patch respectively. All of these are primary skin lesions.

Excoriation and crusts are secondary skin lesions. Wheal, macule and pustule are primary skin lesions.

Primary lesions

Basic lesions that appear on t he skin.

Secondary lesions

Appear later in the disease d ue to scratching or infection.

Primary lesions Secondary lesions

MaculePapulePustulePatchPl aqueNoduleVesicleBullaWhe al

LichenificationErosionExcori ationUlcerCrustScar

The given image shows lichenification.

It is a secondary skin lesion characterized by hyperpigmentation, thickening of the skin, and exaggerated skin markings. It is a feature of chronic eczema.

A macule is a flat, circumscribed, nonpalpable lesion of less than 1 cm that differs in color from the surrounding skin. It can be of any color or shape.

Option B: A patch is a lesion of similar description but of size gt;1 cm. Option C: An ecchymosis is macular area of hemorrhage gt; 1 cm Option D: A papule is a raised lesion lt; 1 cm.

The given biopsy shows parakeratosis. It is associated with visible scales or visible exfoliation of the skin that consists of flakes of stratum corneum.

Parakeratosis refers to the presence of nucleated keratinocytes in the stratum corneum. It is indicative of a high turnover of keratinocytes. It is associated with thickening of the stratum corneum and visibly presents as scaling. The scales represent compacted desquamated layers of stratum corneum.

The following image shows visible fragments of the stratum corneum as it is shed from the skin.

The given image shows collarette scales, which are a characteristic feature of pityriasis rosea.

Collarette refers to a scale with an adherent outer border and detachable inner border. It appears like a rim around the lesion as seen below.

A linear crack or discontinuation of the skin surface is called a fissure.

Option A: Ulcer refers to a loss of dermis and epidermis, often involving underlying tissue as well.

Option B: Excoriation refers to loss of skin substance, specifically produced by scratching.

Option C: Erosion refers to a loss of the epidermis, which heals without scarring. It commonly follows a blister.

This clinical scenario is suggestive of obstructive jaundice, which is associated with severe itching. Hence, you would expect to see excoriations or scratch marks.

The pruritis occurring in obstructive jaundice is due to cholestasis. The bile salts deposit in the skin, causing saponification of the fat surrounding the nerve endings. This leaves the nerves exposed, producing the sensation of a severe itch.

It involves loss of skin substance till the level of the epidermis or upper dermis. Almost all pruritic conditions (except lichen planus) cause excoriation.

The image given below shows excoriations.

The given image showing a round lesion without central clearing is called a nummular (coin-like)

or a discoid lesion.

Both, the edge and center are equally active and uniformly colored. It is seen in discoid eczema, psoriasis.

Option A: Annular lesions are ring-shaped with central clearing i.e., only the edges are active and appear raised, or in a different color. It is seen in tinea corporis, granuloma annulare.

Option C: Arcuate lesions are arc-shaped or incomplete circles.

Option D: Polycyclic lesions are several circles that have merged together.

This image shows fish-like scales on the skin that is characteristic of ichthyosis vulgaris.

It is an autosomal dominant condition that is associated with filaggrin mutations. This leads to a reduction in the natural moisturizing factors (NMF) in the skin. It develops at 3-12 months of life and presents with generalized, itchy, small, light-grey scales and xerosis that are more marked over extensor surfaces and trunk. The groin and flexures are spared.

X-linked recessive ichthyosis occurs only in males. It results in larger, dirty-brown scales.

A bulla is a circumscribed elevation of gt; 1 cm in diameter.

Bullae can be multilocular due to coalesced vesicles, as seen in eczema, or unilocular.

This image shows typical target lesions, characteristically seen in erythema multiforme. It is also called an iris or bull's eye lesion and typically consists of 3 zones as follows:

• Central area of dusky erythema or purpura
• Middle paler zone of edema
• Outer ring of erythema with a well-defined edge

Atypical target lesions with only 2 zones may be seen in Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN).