I think these tutorials would be most useful to 3rd and 4th year Registrars. You need to know a fair bit of dermatology to appreciate the subtle differences between various look alike conditions! The Tutorials should give you a broad overview of clinical dermatology particularly aspects of differential diagnosis. They will use online atlases ,PubMed and eMedicine websites as resource materials as well as the cases in the Dermconsult website itself.
I will illustrate these tutorials better with both a Powerpoint and referral to the Global skin Atlas Website at Global Skin Atlas The format is based on one used by Ken Paver some years ago. Ken set up the Skin and Cancer Foundation in Sydney and was one of the most original and clear thinking dermatologists I have ever met.
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You can view a video of this tutorial below. Any errors then email me at imccoll@ozemail.com.au I think I confuse plane xanthomas and yellow palmar creases with xanthoma disseminatum for starters!
Topics covered in this tutorial
1.DD of the congenital oral leukoplakias
2.DD of erythematous plaques on the cheeks.
3.Lumps on the gums
4.Histiocytosis syndromes
5.Questions on the following conditions-
Gianotti-Crosti syndrome
TORCH syndrome
Pilomatrixoma
Epidermodysplasia verruciformis
Pemphigus vegetans
Juvenile Xanthogranuloma
Rashes of Infectious Mononucleosis
Spitz nevi
Xanthoma disseminatum
Atypical fibroxanthoma
Necrobiotic Xanthogranuloma
THE CONGENITAL ORAL LEUKOPLAKIAS
The differential diagnosis of congenital oral leukoplakias - white sponge nevus, pachyonychia congenita, dyskeratosis congenita, Darier's disease, hereditary benign intraepithelial dyskeratosis.
White sponge nevus is inherited as an autosomal dominant disorder. HPV16 DNA has been identified in some patients. Paradoxically tetracycline antibiotics improve some cases. The lesions can be found in the mouth, the vagina and the rectum Global Skin atlas -Oral Leukoplakia Image
Pachyonychia congenita - thick nails, palmoplantar keratoderma, follicular keratosis of the skin especially on the knees and elbows, blister formation, palmar and plantar hyperhidrosis and leukokeratosis of the mucous membranes. The condition is inherited as an autosomal dominant, but autosomal recessive forms have also been described. Dermnet Pachyonychia Congenita
Dyskeratosis congenita - in contrast there are thin nails with a reticulate pigmentation of the back and atrophy. There are also associated ectodermal and mesodermal changes. The reticulated pigmentation may follow the lines of Blaschko.
Hereditary benign intraepithelial dyskeratosis is associated with pingeculae.
Darier's disease is made up of small white papules on the gingival palate or there may be pebbly areas with verrucous white plaques.
| Condition | Typical onset | Oral pattern | Key extra‑oral features |
|---|---|---|---|
| White sponge naevus | Birth–childhood | Bilateral spongy buccal plaques | Often positive family history |
| Hereditary benign intraepithelial dyskeratosis | Childhood | Corrugated buccal/labial plaques | Recurrent conjunctivitis |
| Pachyonychia congenita | Infancy–early child | Multiple thick oral plaques | Nail dystrophy, painful plantar keratoderma |
| Dyskeratosis congenita | Childhood | Leukokeratosis of tongue/buccal mucosa | Nail dystrophy, reticulate hyperpigmentation, marrow failure |
| Hidrotic ectodermal dysplasia | Childhood | Oral leukokeratosis‑like plaques | Hair/nail changes, palmoplantar keratoderma |
| Frictional keratosis | Any age | Localized rough plaque at trauma site | Evidence of chewing/trauma |
| Chronic hyperplastic candidiasis | Early childhood+ | Non‑wipeable white plaques | Predisposing immunodeficiency or local factors |
HISTIOCYTOSIS SYNDROMES
These are now usually divided into those that are due to a proliferation of Langerhans cells and the others. They include conditions such as histiocytosis X where the acute disseminated form was called Letterer Siwe disease, the chronic progressive was Hand Schuller Christian disease and the benign localised variant was eosinophilic granuloma. The other histiocytic diseases were xanthoma disseminatum, diffuse plane xanthomatosis, juvenile xanthogranuloma and benign cephalic histiocytosis. The latter is usually found on the face and in children less than six months of age and clears often in that time.
eMedicine-Histiocytosis
This photo is of an elderly lady with histiocytosis.Clinically she was initially thought to have Darier's disease.
ERYTHEMATOUS PLAQUES ON THE CHEEKS Search eMedicine Search Perplexity AI
Red plaques are caused by infiltrates of cells, substances or bacteria. Look at the causes below. Usually you need a punch biopsy to make a certain diagnosis.
The differential diagnosis of erythematous plaques on the cheeks include lupus erythematosus, Jessner's lymphocytic infiltrate, polymorphous light eruption, granuloma faciale, lymphocytoma cutis, erysipelas, Sweet's syndrome, mycosis fungoides, leprosy, cold injury, amyloidosis and lichen myxedematosus.
Jessner's lymphocytic infiltrate is usually on the peripheral face generally in older males, particularly on the forehead and cheeks with central clearing. It is made up of polyclonal T cells. Image
Lymphocytoma cutis is usually on the central face, the nose and sometimes the ear lobes. It is usually in young adults. You can sometimes get an epidermal change. Histologically there are usually B cells around lymphoid follicles.
Granuloma faciale is again usually in older men on the nose and cheeks. It can be single or multiple with a peau d orange appearance. It is slow growing and it can vary from skin colour through purple. The histology will show granulomatous infiltration with leukocytoclastic vasculitis.
GSA Granuloma faciale GSA Sub Acute Lupus GSA Erysipelas GSA Lymphocytoma Cutis
This photo shows early discoid lupus
LUMPS ON THE GUMS
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The differential diagnosis of this includes giant cell granuloma, peripheral ossifying fibroma, epulis and pyogenic granulomas.
The term epulis means any benign lesion situated on the gingiva. Most of these are reactive processes with varying degrees of fibrosis, inflammation and vascular proliferation. Giant cell epulis, otherwise known as peripheral giant cell granuloma, is usually found on the gingiva as a bluish red or solitary tumour 1-2cm in diameter near the bicuspids and incisor teeth. Pyogenic granulomas occurring on the gingiva usually occur in pregnancy and may be called a granuloma gravidarum.
eMedicine-Epulis Fissuratum
The photo below shows an epulis
JUVENILE XANTHOMA GRANULOMA
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This is a benign xanthomatous and granulomatous disease of the skin, the mucous membranes and the eyes. It occurs in crops. It usually appears in the first six months of life. The lesions can vary from 1mm-2mm to 20mm in size. It is sometimes associated with neurofibromatosis and patients may develop myeloid leukaemia. The fats are normal. The eye lesions are usually benign. 75% have solitary lesions.
GSA Juvenile Xanthogranuloma eMedicine-Juvenile Xanthogranuloma
XANTHOMA DISSEMINATUM
It is usually seen in males between the ages of five and 25 with yellow brown papules in the flexures and normal lipids. 40% have diabetes insipidus.
eMedicine-Xanthoma Xanthoma Disseminatum-PubMed
This photo shows the typical yellow papules of Juvenile Xanthogranuloma
PILOMATRIXOMA
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These lesions are usually seen in children on the face and forehead. They are stony hard and sometimes lobulated. They are never malignant. They range in size from 3mm to 30mm. Histologically there are dark staining basophilic cells peripherally with more abundant eosinophilic cytoplasm in the middle of the lesion and bone formation.
GSA Pilomatricoma eMedicine-Pilomatrixoma
SPITZ NEVI
These are usually red fairly rapidly growing nevi in children with a histology suggestive of melanoma. They are often spindle shaped cells which stream into the dermis in clusters. There is a dilated dermal vasculature but invasion into the upper epidermis does not occur.
eMedicine-Spitz nevi Dermoscopy Atlas
The photo below is of a pilomatrixoma
Epidermodysplasia Verruciformis
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These are often flat plane wart like lesions on the face. They may be more verrucous elsewhere. 20% may develop a squamous malignancy usually on exposed areas of the skin. The differential diagnosis is acrokeratosis verruciformis which is an inherited disorder, perhaps a form fruste of Dariers disease with flat wart like lesions peripherally on the hands and feet. Epidermodysplasia verruciformis is inherited as an autosomal recessive. The HPV types involved can be those that are seen in normal hosts as well as some types that are unique to epidermodysplasia verruciformis. There seems to be a defect in cell mediated immunity. The condition usually presents in childhood. As well as the papules in the peripheral areas on the trunk, there are sometimes red plaques or hypopigmented very slightly scaly plaques resembling tinea versicolor. If an SCC develops then radiation therapy is contraindicated. Surgical treatment is best.
GSA Epidermodysplasia Verruciformis eMedicine- Epidermodysplasia verruciformis
ATYPICAL FIBROXANTHOMA
This is often misdiagnosed as a pyogenic granuloma, but with the histology of sarcoma in an old person often on the lips, face and neck. Common on sun damaged scalps and in immunosupressed patients. Make sure you do an incisional biopsy to show the base to allow the pathologist to distinguish an AFX from a more serious pleomorphic dermal sarcoma.
eMedicine- Atypical Fibroxanthoma PubMed- Aytypical Fibroxanthoma
The photo below is an atypical fibroxanthoma
NECROBIOTIC XANTHOGRANULOMA
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This is a disease usually of older adults. Characteristically there are periorbital plaques and nodules in about 80% of cases. They may resemble xanthelasmas but they are much deeper, firmer and indurated. They extend into the orbit. The trunk may have plaques that are similar to necrobiosis lipoidica. It is often red in colour with an atrophic centre and superficial telangiectasia. Other eye features include keratitis, uveitis and iritis. There is usually a paraproteinemia.
PubMed-Necrobiotic Xanthogranuloma Image Diagnosis Case
PEMPHIGUS VEGETANS
This is like pemphigus vulgaris but the edges of the blisters develop hypertrophic features. This is particularly seen around the mouth, the anus and the vulva and also in the flexures. The condition can also be seen in the scalp.
GSA Pemphigus Vegetans eMedicine-Pemphigus
This is a photo of necrobiotic xanthogranuloma
GIANOTTI-CROSTI SYNDROME
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This condition is sometimes known as papular acrodermatitis of childhood and is probably a better name. Various viruses are involved. Certain viruses are more common in certain areas of the world. It was initially described in association with hepatitis B virus. It generally affects children. The medium age is two. The lesions are erythematous papules or papular vesicles. They are symmetrical on the face, buttocks and extensor limbs sparing the trunk. Note this is in contrast to most viral exanthems which usually affect the trunk. There may be some associated lymphadenopathy. The condition may last one to two months before slowly resolving.
GSA Gianotti Crosti eMedicine-Gianotti-Crosti
The photos below is an example of the acral extensor papules seen in Gianotti Crosti syndrome
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| Gianotti Crosti |
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| Gianotti Crosti |
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| Gianotti Crosti |
THE SKIN RASHES OF INFECTIOUS MONONUCLEOSIS
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These can be measles like or scarlatiniform, maculo papular, urticarial, purpuric because of thrombocytopenia or even the ampicillin like reaction when Amoxil is given to someone with this disease and a sore throat.
OTHER SKIN LESIONS ASSOCIATED WITH INFECTIOUS MONONUCLEOSIS OR THE EPSTEIN-BARR VIRUS
Some of these have been mentioned already, but other eruptions include a Gianotti-Crosti like. Chronic active Epstein-Barr virus is rare. Two unusual skin eruptions described include a granuloma annulare like eruption and a chronic erythema multiforme like rash. Oral hairy leukoplakia is strongly associated with EBV virus. Oral hairy leukoplakia is commonly seen in AIDS patients but it also occurs in other immunosuppressed hosts especially kidney and bone marrow transplant recipients.
eMedicine-Infectious Mononucleosis
The TORCH Syndrome - this is seen in newborn infants. Some have blueberry muffin lesions representing cutaneous hematopoiesis. There is often hepatosplenomegaly with jaundice and purpura when the children are examined. Various viruses can cause this including cytomegalovirus and infectious mononucleosis.
GSA Blueberry Muffin baby eMedicine-Torch syndrome-Cytomegalovirus
The photo below shows the macular Ampicillin induced drug rash seen in Infectious mononucleosis
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| Ampicillin rash |
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| Ampicillin Rash |
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Questions
1. Are the nails thick in dyskeratosis congenita?
2. Lymphocytoma cutis is usually found on the central face in older males?
3. What two conditions may be found with juvenile xanthogranuloma?
4. Diabetes mellitus is a feature of xanthoma disseminatum?
Click SUBMIT below for the answers to these questions. The photo below is of the lesions seen in the Blueberry muffin syndrome
Answers 1. No. They are thin.Thick nails occur with pachyonychia congenita.
2. It is mainly found on the central face but characteristically in younger adults rather than the elderly. Jessners lymphocytic infiltrate is on the peripheral face in older males.
3. Neurofibromatosis and they may develope myeloid leukaemia.
4. No. It is diabetes insipidus in about 40% of cases.
