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Showcase 40 - 46

Showcase 40

The “Isomorphic Phenomenon of Koebner”

In existing psoriasis, a mechanical stimulus can lead to the local development of typical inflammation. This “isomorphic stimulus effect” was described by Heinrich Koebner in 1872, of patients who scratched themselves, got bitten by horses or had tattoos made, and is therefore also called “Phenomenon of Koebner”. Affected patients need to know that they must not scratch the scabby focuses, as symptoms will worsen within a couple of weeks. The Phenomenon of Koebner also occurs in Lichen ruber and Vitiligo (showcase 38).

Moulage 79

In 1928, in Zurich, volunteer doctor and later famous American dermatology professor Marion Sulzberger scratched his initials into the skin of a patient’s back. Three weeks later the letters appeared “in psoriasis”.

Moulage 756

This moulage was also commissioned by Marion Sulzberger in 1928 for research on the isomorphic stimulus effect. He scratched the name of the former director of the Clinic of Dermatology, Bruno Bloch, on the back of his patient, who was affected by Lichen ruber.


Lichen ruber planus

This common skin disease typically shows itchy papules. It is not contagious and proceeds often chronically over weeks or even years. In contrast to eczema or prurigo, skin changes are not scratched open, but rubbed.

Moulage 147

The papules of Lichen ruber are flat, polygonal, sharply bordered, and have a typical shine to them. The partly linear arrangement is attributed to the isomorphic stimulus effect after rubbing.

Moulage 1217

Lichen ruber, spread over a large area, and with isomorphic stimulus effect.

Moulage 1285-1287

A typical localisation of the sharply bordered, and over time brownish-reddish papules and plaques, are the insides of the wrists and the lower back. The healed inflammation often leaves long-standing brownish spots behind.

Moulage 1282

Oral mucosa can be affected separately. Lichen ruber in the mouth is very difficult to treat and often proceeds chronically over decades. In rare cases, skin cancer develops out of the chronically inflamed erosions over time. Therefore, regular medical checks are important.
Additional moulages on autoimmune diseases in showcase 51.


Nail diseases

Catalogue p. 55

Moulage 1312

Stress on the organism due to illness, intoxication or medication can lead to hair loss and nail growth disorders which may heal with a delay of several weeks. Apparently, the patient shown here had at least two severe attacks of disease over the last months, as can be seen in the two longitudinal grooves on the nails.

Moulage 703

Various skin diseases may trigger inflammations in the growth area of nails, and trigger changes in the nail plate. Thus, in patients with circular hair loss (the causes of which are unknown), scaled-off nail plates, called sandpaper nails, may be observed.

Moulage 1185

Crooked nails or claw nails are mainly observed on the big toes of elderly people. Presumably, the main cause is chronic, mechanical stress and pressure due to tight shoes.

Moulage 913

A pigmented birthmark around the area of nail growth may pigment the nail. This way, a brownish line appears along the nail plate. A newly appearing melanonychia may indicate black skin cancer, especially if the brown streak gets wider over time (contrary to the one shown here).

Showcase 41


Catalogue p.85

Paraneoplasias are skin reactions to malign tumours (neoplasias) on internal organs. Facultative neoplasias are skin diseases which can emerge for other reasons (Dermatomyositis, showcase 34). Obligate paraneoplasias always emerge as a symptom of cancer. The search for the triggering tumour is mandatory. Once the tumour is detected and being treated, the skin disease disappears as well.

Moulage 638 and 1203

Erythema gyratum repen as well as Akanthosis nigricans are obligate paraneoplasias.


Diseases of the sebaceous glands

The sebaceous gland forms a unit with the hair root. The sebum produced by them lubricates the skin. With the onset of puberty, sebaceous glands increase their activity under the influence of male sex hormones.


Catalogue p. 64

Sebaceous follicles are frequently found in the face, on décolleté and shoulder area. In acne these are enlarged, congested and inflamed. Acne is one of the most common skin diseases and occurs during puberty in varying severity in almost every human being, most often subsiding in early adulthood.
Acne is often trivialized and undertreated despite stressful aesthetic implications. Often lifelong scarring remains. However, successful therapies exist. Skin cleansing and diet have almost no influence on the progression.

Moulage 1302

The enlarged or congested sebaceous glands appear as fine, bright papules or as black points (blackheads, comedones). Inflammatory reactions lead to pustules, knots, abscesses and scars.



Catalogue p.65

Early signs for Rosacea are redness in the face due to enlarged fine blood vessels (Telangiectasias). During further course, inflammatory papules, pustules or swellings, and enlarged sebaceous glands occur.

Moulage 82

Particularly during a moisturising or cortisone therapy, inflammations may develop distinctively and become granulomatous.

Moulage 397

Rhinophyma is a special form of Rosacea. Due to the swelling of the connective tissue and the sebaceous glands, an increasingly disfiguring hammer nose develops. It can be surgically ablated with excellent cosmetic results.


Acne inversa (Hidradenitis suppurativa)

Catalogue p. 65

Moulage 1225

The chronic abscesses with scarring in the axillae or inguinal area start in adulthood. Smokers are particularly affected. Persistent areas are best removed by plastic surgery.
Additional moulages on autoimmune diseases in showcase 52, left side.

Showcase 42

Diabetic skin changes

Catalogue p. 86

Most of the skin changes related to Diabetes mellitus are attributed to damages of small blood vessels and nerves.

Moulage 104

The absence of the sense of pain on the sole of foot often leads to deep ulcerations due to inappropriate or chronic pressure. 

Moulage 162

Due to the occlusion of fine blood vessels, single toes can die off.
Additional moulages on autoimmune diseases in showcase 51, bottom.


Physically induced dermatosis
Chronic UV-damages

Catalogue p. 71

Chronic UV-exposure is responsible for photoaging with wrinkles, stains, redness and cysts of the skin.

Moulage 24

“Sailor skin”: deep wrinkles in the neck due to excessive chronic UV-exposure.


Phototoxic reactions

Catalogue p. 70

Phototoxic substances increase the light sensitivity of the skin.

Moulage 42

Phototoxic substances occur in Giant hogweed, fig leaves and in grasses. The stripe-like reaction reflects the contact with wet grasses followed by sunlight exposure (for example on a sunny lawn after swimming).


Photoallergic reactions

Catalogue p. 71

Moulage 787

Experimental sensitization with photoallergic reaction to Benzopyrene. The allergic reaction is caused only in combination with light.


Polymorphic light eruption

Catalogue p. 72

“Sun allergy” or polymorphic light eruption is common. Augmented sunlight exposure causes an oftentimes itchy inflammatory reaction.
Hydroa vacciniformia

Moulage BS 3

Hydroa vacciniformia is a rare, severe reaction to light, similar to polymorphic light eruption.


Radiation Damage, X-rays, and Ionizing Radiation

Catalogue p. 69

Ionizing (radioactive) radiation in high dosing leads to chronic inflammatory skin changes: Skin thinning, keratinization disorder, vessel enlargement. Decades later, ulcerations and white skin cancer may develop.

Moulage 539

For a long time, long-term consequences of X-ray therapy were underestimated, and relatively harmless skin problems like increased hair growth on the chin of this woman was treated generously with X-rays.

Moulage 156

X-ray atrophy two years after radiation because of tuberculosis of the rib.

Showcase 43

Thermal Damage
Frostbite (Congelatio)

Catalogue p. 67

Moulage 1290

Third degree frostbite with necrotic tissue of the fingertips.
Frostbite (Pernio)
Frostbites are blueish-reddish swellings which can be itchy or painful. They are caused by low temperatures and wetness.

Moulage 1241

Typical localisations of pernios are fingers and toes, but also the exterior thigh.


Benign tumours and birthmarks (Naevi)
Infantile hemangioma (strawberry mark)

Catalogue p. 73

Moulage 1277

As early as at birth or during the first weeks of life, a reddish, fast growing spot may be determined which becomes increasingly tuberous. Up to age 9, about 90% of the hemangioma regress, leaving a scar behind.

Moulage 1245

In the past, an extended hemangioma was treated with X-rays. In these patients, the tuberous parts returned.



Catalogue p. 73

Scars may be flat, sunken or protruding. Keloids are massive proliferating scar reactions. Risk spots are the chin, ears, breastbone and the upper arms, especially on people with dark skin.

Moulage 1237

On predisposition, keloids may emerge “spontaneously” from smallest injuries, for example due to slight acne.


Naevus flammeus (birthmark)

Catalogue p. 75

The naevus flammeus is not a tumour but a malformation with dilation of the vessels, and with an incidence of about 2% in new-borns.

Moulage 1316

Larger birthmarks grow with the child and do not disappear by themselves. Cosmetically disturbing birthmarks can best be removed with laser therapy.


Naevus (birthmark)

Catalogue p. 74

A naevus is a benign malformation of the skin or the mucous membrane with faulty distribution of the cells, a sort of “knitting error” in the tissue. Pigmented naevi can look similar to dark skin cancer (melanoma), and some melanomas evolve from birthmarks.

Moulage 262

Disorders of the genetic cell-structures during embryonal growth may lead to linearly arranged keratinization.

Moulage 250-253

Numerous pigmented naevi, existing from birth. Due to the deep localisation of the brown pigment in the skin, some of the birthmarks appear bluish-black.
Additional moulages on benign tumours in showcases 52, right side and 53, left side.

Showcase 44

Seborrheic keratosis (Verruca seborrhoica)

Catalogue p.75

Moulage 1248

Seborrheic keratosis is sometimes hard to distinguish from a dangerous melanoma or a basal cell carcinoma.

Moulage 591

In the course of life, harmless, rough, brown-grey-black keratinization may develop everywhere on normal skin.


Urticaria pigmentosa

Moulage 1022

Within the brownish-reddish spots numerous mast cells accumulate which can release histamine. Due to mechanical stress, the spots may swell and form wheals. Sometimes, because of the histamine reaction, they may even form blisters. Especially insect bites can lead to dangerous “allergic” reactions. The excessive increase of mast cells develops chronically, may affect inner organs or, in rare cases, even become malignant.
Precancerous lesions
Individual factors, genetic predisposition, inflammatory diseases and the influence of cancer-promoting environmental factors like UV-light, viruses or medicaments can influence the development of malign skin tumours. Precancerous lesions are precursors of skin cancer.


Actinic keratosis

Catalogue p. 77

Chronic cumulative UV-stress on the skin can lead to hyperkeratinisations, which are precursors of skin cancer. Therapy at an early stage is easy and prevents the development of skin cancer. Consequent light protection prevents the progression and new formation of actinic precancerous lesions.

Moulage 1176

Palpable thickening, as this case on the nose or in the temple area, is a sign for the development of a squamous cell carcinoma.

Moulage 627

The hyperkeratinisation of actinic precancerous lesions can lead to horn-like “warts”.


Morbus Bowen

Catalogue p. 79

This precursor of skin cancer looks similar to psoriasis.

Moulage 505-6

Nowadays, extended precancerous lesions are still treated successfully with X-rays.


Lentigo maligna

Catalogue p.79

Moulage 1264

Precursors of black skin cancer can emerge on UV-stressed skin of elderly people. They almost cannot be distinguished from harmless “age spots”.



Catalogue p.77

Moulage 500

Leucoplakia is a white keratinization on the mucous membrane. It may be a reaction to mechanical stress due to tooth damage or cheek chewing. Leucoplakias due to tobacco consumption are precancerous lesions.
Additional moulages on precancerous lesions in showcase 53, left side.

Showcase 45

Basal cell carcinoma (BCC)

Catalogue p. 80

The basal cell carcinoma is the most common tumour in human beings. Fortunately, it rarely metastasizes. Particularly at risk are people with light skin and chronic UV-exposure.

Moulage 1272

Nodular Basal cell carcinoma.

Moulage 520

Without adequate therapy, a wound develops with destruction of the surrounding tissue.

Moulage 1004

The basal cell carcinoma starts as an inconspicuous thickening of the skin.

Moulage 1301

Without investigation by magnifying glass (dermatoscope) or biopsy, the pigmented basal cell carcinoma is hardly distinguishable from a melanoma.

Moulage 1469

Scarred basal cell carcinoma with invisible branches.

Moulage 1134

This superficial form of a basal cell carcinoma is often misinterpreted as an eczema or psoriasis.


Spinocellular carcinoma (Squamous Cell Carcinoma/SCC)

Catalogue p. 81

The Squamous Cell Carcinoma emerges from precancerous lesions (see showcase 44) on chronically damaged skin. The most common reason is chronic UV-exposure. It can metastasize, however, fortunately mostly in advanced cases.

Moulage 651-52

Spinocellular carcinoma caused by chronic exposure to coal, heat and sunlight at work as a train driver.

Moulage 1032

Because of chronic unilateral sunlight exposure, this patient developed Spinocellular carcinoma only on the right half of her face.

Moulage 930

Areas affected by chronic UV-exposure are the face, hands and the bald head of men.

Spinocellular and Basal cell carcinoma are also called “white skin cancer” as a differentiation to the much more dangerous melanoma. The frequency has been increasing dramatically over the last decades.

Additional moulages on skin cancer in showcase 53.

Showcase 46

Melanoma (black skin cancer)

Catalogue p. 82

Melanoma is one of the most dangerous types of cancer because it metastasizes rapidly. The earlier the melanoma is surgically removed, the better the long-term prognosis.

Risk factors: familiar burdening, repeated sunburns, light skin type, presence of many birthmarks.

Moulage 1311

ABCDE-Rule: Look for these signs: Asymmetry, irregular Borders, more than one or uneven distribution of Color, or a large (greater than 6mm) Diameter. Finally, pay attention to the Evolution of your moles - know what is normal for your skin and check it regularly for changes. 

Catalogue p.83.

Moulage 1119

Melanoma, developed from a Lentigo maligna (see also showcase 44)

Moulage 519

Melanoma with metastasis in the surrounding skin.

Moulage 640

Acral Melanoma.


Morbus Paget of the breast

Catalogue p. 83

Moulages 513-515

Morbus Paget is a breast cancer which can spread onto the skin and looks like an eczema.



Catalogue p. 83

Lymphoma is a malignant tumour originating from white blood cells, developing in lymph nodes or on the skin. The prognosis is usually very good.

Moulage 294

Sézary-Syndrome: Lymphoma with a chronic inflammation of the entire skin.

Moulage 3

Mycosis fungoides: chronic eczema-like spots (patches) in which palpable plaques, nodes and wounds can develop after years.


Kaposi Sarcoma

Catalogue p. 84

Moulages 566 and 1256-1257

The Kaposi Sarcoma is a malignant tumour, triggered by the human herpesvirus 8. It emerges often as a result of a weakened immune system, for example in HIV (AIDS) or due to medical immunosuppression after an organ transplant.


Metastasis (offshoots of malignant tumours)

Catalogue p. 84 

Moulage 1341

Every malignant tumour can metastasize into the skin.

Additional moulages on skin cancer in showcase 53.