Basal cell carcinoma (BCC)


  • NMSC are not registered by most cancer registries; therefore the incidence of NMSC can only be approximated.
  • The estimates are based on a series of nation-wide surveys, the most recent of which was conducted in 2002. Due to the high numbers of untreated and undiagnosed NMSC, surveys are likely to underestimate the true rates of NMSC in Australia.
  • About 67% of skin cancers in Australia are BCC (Thursfield 2007). The annual age-standardised incidence of BCC in Australia is estimated to be 884 people per 100,000 (1041 in men and 745 in women) (Staples et al 2006). The risk of developing a BCC before the age of 70 is 59% for Australian males, and 48% for Australian females (Staples et al 2006).
  • Between 1985 and 2002, an overall increase in the age-standardised rates of BCC was detected. However, the rates of BCC for people younger than 60 years did not increase (Staples et al 2006). Since the major determinant of lifetime risk for skin cancer is childhood and adolescent sun exposure, this is supportive evidence that the public health campaigns to reduce sun exposure may be starting to have an effect on skin cancer rates (Thursfield 2007) (Staples et al 2006).
  • BCC are more likely to be found in:
    • Males.
    • People over the age of 40.
    • People with high levels of cumulative sun exposure.
    • Outdoor workers.
    • People living closer to the equator. The highest rates for BCC are found in northern Australia.
  • BCC arises on parts of the body that are chronically exposed to the sun – over half are found on the head and neck, a quarter to a third is found on the trunk and smaller proportions are found on the limbs. The anatomical distribution of BCC is similar for men and women.Distribution of BCC by body site and sex (Staples et al 2006)

Body Site



Head and Neck













  • The strongest predictor of BCC is clinical evidence of chronic sun damage, reflecting total lifetime cumulative exposure to the sun and skin phenotype.
  • Other risk factors associated with BCC are (2008, Cancer Council Australia and Australian Cancer Network: Sydney).
    • Exposure to ionizing radiation therapy.
    • Exposure to arsenic.
    • Scars (especially vaccination scars).
    • Immunosuppression, especially after organ-transplantation and use of glucocorticoids.
    • Gorlin’s syndrome (a rare autosomal dominant disorder, characterized by the development of multiple BCC at a young age)
    • Xeroderma Pigmentosum (a rare autosomal recessive disorder in which a DNA repair gene is abnormal, preventing repair of UV-induced DNA damage).
  • Sunscreen use has shown an association with decreased BCC occurrence, especially repeated BCC occurrence (Pandeya et al 2005).


There are three common histological growth patterns of BCC:

  1. Nodular,
  2. Superficial and
  3. Infiltrating.

Each type has a distinct clinical presentation.
Superimposed on any of these three patterns may be ulceration and/or pigmentation.

Nodular BCC: ulcerated red nodule on the nose.

Nodular BCC: ulcerated red pre-auricular nodule.

BCC dermoscopic view

Superficial BCC on the right calf: scaly, erythematous lesion with ulceration, more common on the limbs and trunk.

Right Cheek Nodular BCC macroscopic.

Superficial BCC on back: scaly erythematous lesion, slow growing.

Superficial BCC on forehead: scaly erythematous lesion, slow growing.

SBCC on Right arm; scaly, pink, slow growing lesion.

Pigmented BCC macroscopic.

Pigmented BCC dermoscopic view.

Morphoeic / Infiltrating BCC on the posterior ear: shows a scarred, ulcerated, ill defined edge: more ill defined than a nodular BCC.

Morphoeic / Infiltrating BCC on the forehead: scar like ulcerated area, ill defined.

Morphoeic/ Infiltrating BCC: this can be difficult to diagnose.

Morphoeic/ Infiltrating BCC.


  1. Basal cell carcinomas, like other skin cancers, are changing lesions.
  2. Changes occur generally over a period of months. Some lesions may be symptomatic.
  3. Asking about change and symptoms of a lesion can be very helpful in the diagnosis of BCC.

    Distribution Clinical Features Clinical Course Differential Diagnosis Notes
    Superficial BCC Trunk and limbs are common sites. Quite well defined erythematous, scaling or slightly shiny macule.

    Mostly asymptomatic.

    May be itchy.

    Rarely ulcerate/bleed.

    Enlarge progressively over months to years. Some remain stable and a few regress. Solar keratosis, Bowenoid keratosis, SCC in situ (Bowen’s disease), amelanotic melanoma, psoriasis, eczema. A biopsy prior to definitive treatment of a single localized erythematous scaling lesion is recommended.

    May affect younger people more often than other types of BCC.

    Nodular BCC Head and neck are the commonest sites. Shiny, pearly, papule or nodule with telangiectatic vessels. Stretching the skin enhances pearly features. May see central umbilication with a raised, rolled edge.

    Commonly asymptomatic. Frequently ulcerate and bleed.

    Progressively enlarge and ulcerate over months to years. SCC, amelanotic nodular melanoma, Merkel cell carcinoma. (rare) Tend to affect older people than superficial BCC
    Morphoeic BCC Similar to nodular BCC. Resemble a pale scar. Firm induration usually palpable.

    Frequently asymptomatic.

    May remain undetected for years.

    Enlarge and invade deeply and may become very large.

    Scar A biopsy is recommended to obtain definitive diagnosis.

    Depth and extent of spread may be underestimated on clinical examination.


  4. Dermoscopy may be useful in enhancing the diagnosis of BCC. Appropriate training and skill maintenance must be observed.
  5. Thick Arborizing (branching) vessels are a common finding in basal cell carcinoma.
  6. Dermoscopy of superficial BCC (sBCC) may reveal a milky pink background, arborizing microvessels, atypical or telangiectatic vessels, a scattered vascular pattern and brown dots/globules (Pan et al 2008). The diagnostic accuracy for sBCC is around 99% if arborizing microvessels, atypical or telangiectatic vessels and a scattered global vascular pattern are present (Pan et al 2008).Arborizing vessels are a typical dermoscopic finding of nodular BCC.


  1. Biopsy is recommended to confirm the diagnosis of a suspected BCC prior to definitive therapy. Margin-controlled orientated complete excision is the preferred approach as this enables examination of the architecture of the tumour and assessment of the adequacy of excision.
  2. In some circumstances complete excision may not be appropriate, in which case partial biopsies, for example punch or shave biopsies may be useful.
  3. Important features on the pathology report that may influence further treatment and prognosis are:
    1. Subtype (nodular, superficial, infiltrated or other (e.g. micronodular, sclerotic).
    2. Adequacy of excision.
    3. Perineural invasion. (See Example Below)

Nodular BCC growth pattern.

Nodular BCC growth pattern.

Superficial BCC growth pattern.

Infiltrating BCC growth pattern.


(p 33-35 ACN guidelines) (Cancer Council Australia and Australian Cancer Network 2008)

BCC rarely metastasise. Prognosis is best assessed in terms of recurrence rates over time. Local recurrence depends on the following factors:

  1. Size and depth of invasion – The following table outlines the overall estimated control rates of treated primary BCC by stage.

T stage

Clinical Size


% Control rates at 5 years





>2cm but <5cm





T4 tumour deeply invaded beyond subcutaneous tissues.


  1. Incomplete excision – Incomplete excision is accompanied by a 30% recurrence rate.
  2. Previous recurrence – For early stage tumours, recurrence rates after treatment of previously treated (recurrent) BCC are reported in the range of 15-30% compared with previously untreated (primary) BCC of 1-10%.
  3. Anatomical site – BCC on the face recur more frequently than BCC on non-facial sites.
  4. Histological subtype – Morphoeic, infiltrating and micronodular subtypes are more likely to recur than superficial and nodular subtypes.
  5. Treatment modality – Surgical excision is associated with the lowest recurrence rates.
  6. Perineural spread – this is a rare feature in BCC but indicates a tumour with greater invasive potential.


  1. Surgical excision is the treatment of choice for BCC. The advantages of surgical excision of BCC are that it achieves the best cure rates, provides the best specimen for histological assessment of diagnosis and to assess adequacy of removal, and generally results in cosmetically and functionally acceptable outcomes.
  2. Most clinically favourable BCC (i.e. small, nodular or superficial subtypes, not located on the central face) can be excised under local anaesthesia with 2-3 mm margins with a high chance of achieving long-term local control. Adequate microscopic margins are 1mm (Cancer Council Australia and Australian Cancer Network: Sydney 2008). One study showed the recurrence rate of primary non-multifocal BCC excised with greater than 0.5 mm margins to be 1.2%, compared with a recurrence rate of 12% for tumours excised with less than 0.5 mm margins (Pascal et al 1968). 33% of BCC recurred if the tumour was present at the margin of the excision. If an aggressive form of BCC (morphoeic, infiltrating or micronodular) is suspected either clinically or on biopsy, then a margin of 3-4 mm is appropriate (Cancer Council Australia and Australian Cancer Network: Sydney 2008).
  3. Consider referral to a specialist in the following scenarios (Cancer Council Australia and Australian Cancer Network: Sydney 2008):
    1. Recurrent lesions.
    2. Incompletely excised lesions.
    3. High risk subtypes, for example morphoeic, infiltrating and micronodular subtypes.
    4. Lesions on the ears, central face, hands, leg, genitalia.
    5. Poorly defined lesions.
    6. Lesions fixed to underlying structures.
    7. Lesions involving or lying near important nerves.
    8. Trunk and extremity lesions greater than 20 mm.
    9. Cheek, forehead and scalp lesions greater than 10 mm.


  1. Mohs micrographic surgery is a technique in which a tissue specimen is carefully marked at time of excision and the entire outer margin (peripheral and deep) is examined by paraffin section.
  2. The technique aims to achieve complete histological clearance of the lesion, while maximizing conservation of normal tissue and function.
  3. Careful marking of the specimen at excision enables precise localisation of any residual tumour. If residual tumour is detected, further tissue, at the site corresponding to the mapped residual tumour, is excised.
  4. The process is repeated until the tumour is completely removed.
  5. The procedure is time consuming and labour intensive and is performed mostly in tertiary referral services.
  6. Slow Mohs surgery is necessary only for a very small proportion of skin cancers.
  7. Referral for Slow Mohs surgery should be made by a medical practitioner with experience in skin cancer management and may be considered in the following scenarios:
    1. Recurrent tumours.
    2. Tumours with poorly defined borders, particularly those with aggressive growth patterns, in anatomically difficult areas, where conservation of normal tissue and function is important.
    3. Extensive tumours.


  1. There may be circumstances in which surgical excision of a BCC is inappropriate. For example, elderly and high risk surgical patients or patients who refuse surgery.
  2. In general, therapies other than surgical excision should be reserved for small, well-defined, primary superficial BCC. Histological confirmation of the diagnosis of BCC and exclusion of high risk features should be performed before any non-surgical treatments are commenced.


  1. Imiquimod 5% cream “Aldara”®
    1. This agent is approved for use for primary superficial BCC in immunocompetent patients that are not appropriate for surgical excision, cryotherapy or curettage with diathermy. The lesion must be previously untreated and the diagnosis confirmed on biopsy.
    2. Histological diagnosis prior to treatment is required.
    3. Histological clearance rates of around 82% have been shown in some studies. (Cancer Council Australia and Australian Cancer Network: Sydney 2008).
    4. The cream is applied to the tumour and 5 mm of surrounding skin for 5 days of the week for six weeks. Clinical assessment regarding efficacy is made 2-3 months after therapy.
    5. 5% Imiquimod cream can lead to a severe local inflammatory skin reaction.
  2. Photodynamic therapy (PDT)
    1. Three-month clearance rates of primary superficial BCC with methyl aminolevulinate-PDT have been reported to be between 80% and 97% (Cancer Council Australia and Australian Cancer Network: Sydney 2008).
    2. Referral to a specialist centre is required for PDT.


These methods are simple, cheap and quick to perform. However, their efficacy is highly dependent on the experience of the operator and the suitability of the lesion. The recurrence rates for BCC treated with these modalities tend to be higher than for those treated with margin-controlled surgical excision.

  1. Curettage and diathermy/electrodessication
    1. This technique requires specialist training.
    2. It may be appropriate for superficial BCC on the trunk and limbs.
    3. Higher recurrence rates are seen for larger tumours, previously treated lesions and lesions on the head.
    4. May have unpredictable cosmetic outcomes.
  2. Cryotherapy
    1. This technique may be suitable for well-defined primary BCC, of non-aggressive subtype, at sites other than the head and neck.
    2. Cryotherapy is contraindicated for ill-defined or morphoeic BCC and for BCC on high risk sites such as the head and neck.
    3. Cure rates are highly technique dependent. Cure rates greater than 95% are frequently reported from specialty clinics (Graham 1983, Holt 1988, Zacarian 1983), whereas, unacceptably low cure rates have been reported in the context of suboptimal cryotherapy technique (Hall 1986).
  3. Radiotherapy
    1. Requires referral to a specialist centre.
    2. Is only appropriate for a small proportion of primary BCC, for which complete excision is contraindicated or not feasible.
    3. 5-year control rates for small primary BCC are around 95% (Avril 1997, Fitzpatrick 1984, Wilder et al 1991).


  1. There is a small risk of recurrence of BCC, which depends on the size, site and initial mode of treatment as discussed above.
  2. The risk of metastasis is very low.
  3. However, patients who have been treated for a primary BCC are at risk of developing further primary BCC and other skin cancers.
  4. Regular full skin checks, during which the site of the initial tumour is assessed for evidence of recurrence and the entire skin surface is assessed for further primary skin cancers and other sun related lesions, are reasonable.
  5. Patients are encouraged to seek medical guidance if a worrisome or changing skin lesion is noticed; regular self-assessments should be performed by patients as well.


  1. Thursfield, V. and G. Giles, eds., Canstat No. 44, in Skin Cancer. 2007, Cancer Epidemiology Centre The Cancer Council Victoria: Melbourne.
  2. Staples, M., et al., Non-melanoma skin cancer in Australia: the 2002 national survey and trends since 1985. Medical Journal of Australia, 2006. 184: p. 6-10.
  3. Basal cell carcinoma, squamous cell carcinoma (and related lesions) – a guide to clinical management in Australia. 2008, Cancer Council Australia and Australian Cancer Network: Sydney.
  4. Pandeya, N., et al., Repeated occurrence of basal cell carcinoma of the skin and multifailure survuval analysis: follow-up data from the Nambour Skin Cancer Prevention Trial. American Journal of Epidemiology, 2005. 161(8): p. 748-754.
  5. Pan, Y., et al., Dermatoscopy aids in the diagnosis of the solitary red scaly patch or plaque – features distinguishing superficial basal cell carcinoma, intraepidermal carcinoma, and psoriasis. Journal of the American Academy of Dermatology, 2008. 59(268-274).
  6. Pascal, R., et al., Prognosis of “incompletely excised” versus “completely excised” basal cell carcinoma. Plastic Reconstructive Surgery, 1968. 41(4): p. 328-332.
  7. Graham, G., Statistical data on malignant tumours in cryosurgery;1982. J Dermatol Surg Oncol, 1983. 9(3): p. 238-9.
  8. Holt, P., Cryotherapy for skin cancer: results over a 5-year period using liquid nitrogen spray cryosurgery. British Journal of Dermatology, 1988. 119(2): p. 231-240.
  9. Zacarian, S., Cryosurgery of cutaneous carcinomas. An 18-year study of 3,022 patients with 4,228 carcinomas. Journal of the American Academy of Dermatology, 1983. 9(6): p. 947-956.
  10. Hall, V., et al., Treatment of basal-cell carcinoma: comparison of radiotherapy adn cryotherapy. Clin Radiol, 1986. 37(1): p. 33-34.
  11. Avril, M., et al., Basal cell carcinoma of the face: surgery or radiotherapy: Results of a randomized study. British Journal of Cancer, 1997. 76(1): p. 100-106.
  12. Fitzpatrick, P., et al., Basal and squaous cell carcinoma of the eyelids and their treatment by radiotherapy. International Journal of Radiation Oncology, Biology, Physics, 1984. 10(4): p. 449-454.
  13. Wilder, R., J. Kittelson, and D. Shimm, Basal cell carcinoma treated with radiation therapy. Cancer, 1991. 68(10): p. 2134-2137.

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Molluscum contagiosum




What is onycholysis?

Onycholysis is a common nail disorder. It is the loosening or separation of a fingernail or toenail from its nail bed. It usually starts at the tip of the nail and progresses back.

Pseudomonas infection
Traumatic onycholysis
[see X-ray]
Fracture underlying
traumatic onycholysis
Onycholysis and
subungual hyperkeratosis

What causes onycholysis?

Many things may cause onycholysis. Some of the most common causes are:

  • Repetitive trauma, e.g. daily tapping of long fingernails on a keyboard or counter


  • Overzealous manicure, e.g. manicure tools pushing beneath the nail to clear dirt and overuse of nail cosmetics
  • Prolonged immersion of nails in water.

Other causes of onycholysis are shown in the following table.

Cause Examples
Skin disease Psoriasis, dermatitis and less often, pemphigus vulgaris, porphyria cutanea tarda and others
  • Dermatophyte fungus (i.e., Trichophyton rubrumT. mentagrophytes infection)
  • Yeast (Candida infection)
  • Bacteria (Pseudomonas infection)
  • Virus (Herpes simplex infection)
Internal disease (uncommon) Amyloid and multiple myeloma, anaemia (iron deficiency), diabetes mellitus, erythropoietic porphyria, hyperhidrosis hyperthyroidism, impaired peripheral circulation, leprosy, pellagra, psoriatic arthritis, Reiter syndrome, sarcoidosis, scleroderma, yellow nail syndrome due to chronic lung or sinus disease
  • Tetracyclines
  • Psoralens
  • Fluoroquinolone antibiotics
  • Chlorpromazine
  • Oral contraceptives
  • Some anti-cancer treatments
Other Congenital onycholysis, hereditary partial onycholysis, idiopathic acquired onycholysis, hereditary distal onycholysis, foreign body implantation,contact allergy to nail glue (acrylate)

Who gets onycholysis and how is it diagnosed?

People of all ages, sex and race can get onycholysis, although it is more frequently seen in female adults.

Because so many things can cause onycholysis, your doctor may examine you to check for other skin conditions or medical problems such as thyroid disease. If a fungal infection is suspected, your doctor may clip the nail and scrape a sample of tissue from beneath the nail plate for laboratory testing

What are the signs and symptoms of onycholysis?

  • Irregular border between the pink portion of the nail and the white outside edge of the nail when the nail has lifted from the nail bed.
  • Larger portion of the nail is opaque, can be whitened or discoloured to yellow or green.
  • Discoloration underneath the nail may occur as a result of secondary infection.
  • Depending on the cause, the nail may collect thickened skin underneath the edge of its nail plate and the nail surface may become deformed with pits or indentations.
  • It is usually painless as the separation occurs gradually. Pain may occur if nail is further detached from the nail bed as result of trauma or if active infection sets in.

What is the treatment for onycholysis?

Treatment of onycholysis depends on the cause of the problem. Eliminating or correcting the predisposing cause is the best treatment. For example, treatment of hyperthyroidism will allow the nails to regrow normally and nail infections can be treated with antimicrobials.

The portion of nail that has separated will not reattach to the nail bed and you will have to wait until the nail is fully regrown for the condition to be completely gone. Fingernails take 4-6 months to fully regrow whilst toenails may take twice as long.

To prevent deterioration or recurrence of onycholysis after it has cleared up:

  • Clip the affected portion of the nail, and keep the nails short.
  • Avoid injuring the affected nail, and keep the nail bed dry.
  • Avoid exposure to contact irritants such as nail enamel and enamel remover or solvents and detergents.
  • Wear light cotton gloves under vinyl gloves for wet work.


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Photocontact dermatitis

Seborrhoeic keratoses

Pyoderma gangrenosum

What is pyoderma gangrenosum?

Pyoderma gangrenosum presents as a rapidly enlarging, very painful ulcer. It is one of a group of autoinflammatory disorders known as neutrophilic dermatoses.

The name pyoderma gangrenosum is historical. The condition is not an infection (pyoderma), nor does it cause gangrene.

Who gets pyoderma gangrenosum?

Pyoderma gangrenosum is an uncommon disease that affects males and females of any age, but is more common in those aged over 50 years. It is thought to be a reaction to an internal disease or condition. Known associations include:

  • Inflammatory bowel disease (ulcerative colitis and Crohn disease)
  • Rheumatoid arthritis
  • Myeloid blood dyscrasias including leukaemia
  • Monoclonal gammopathy (usually IgA)
  • Chronic active hepatitis
  • Granulomatosis with polyangiitis
  • PAPA syndrome
  • Use of levamisole-adulterated cocaine
  • Miscellaneous less common associations.

However, about 50% of those affected by pyoderma gangrenosum have none of the associated risk factors.

What causes pyoderma gangrenosum?

Pyoderma gangrenosum is an autoinflammatory disease (excessive response to an internal antigen) due to some form of neutrophil dysfunction.

Clinical features of pyoderma gangrenosum

Pyoderma gangrenosum usually starts quite suddenly, often at the site of a minor injury. It may start as a small pustule, red bump or blood-blister. The skin then breaks down resulting in an ulcer. The ulcer can deepen and widen rapidly. Characteristically, the edge of the ulcer is purple and undermined. Pyoderma gangrenosum is usually very painful. Several ulcers may develop at the same time.

Untreated, the ulcers may continue to enlarge, persist unchanged or may slowly heal. Treatment is usually successful in arresting the process, but complete healing may take months. This is particularly true if there is underlying venous disease, another reason for leg ulcers.

Deep ulcers heal with scarring and this is sometimes with a characteristic cribriform or criss-cross pattern. A rare superficial bullous variant of pyoderma gangrenosum may heal without leaving a scar. This may be similar to or confused with acute febrile neutrophilic dermatosis (Sweet disease).

Pyoderma gangrenosum

How is pyoderma gangrenosum diagnosed?

Pyoderma gangrenosum is diagnosed by its characteristic appearance. There is no specific test. The wound should be swabbed and cultured for micro-organisms, but these are not the cause of pyoderma gangrenosum. Biopsy may be necessary to rule out other causes of ulceration. Pyoderma gangrenosum characteristically results in a neutrophilic inflammatory infiltrate but this is not always present.

Mostly, blood tests are not particularly helpful. Some patients may have a positive ANCA (antineutrophil cytoplasmic antibody).

The pathergy test is usually positive (a skin prick test causing a papule, pustule or ulcer).

Treatment of pyoderma gangrenosum

Treatment is non-surgical. The necrotic tissue should be gently removed. Wide surgical debridement should be avoided during the active stage of pyoderma gangrenosum because it may result in enlargement of the ulcer.

Often conventional antibiotics such as flucloxacillin are prescribed prior to making the correct diagnosis. These may be continued if bacteria are cultured in the wound (secondary infection) or there is surrounding cellulitis (red hot painful skin), but they are not helpful for uncomplicated pyoderma gangrenosum.

Small ulcers are best treated with:

  • Potent topical steroid creams
  • Tacrolimus ointment
  • Intralesional steroid injections
  • Special dressings
  • Oral anti-inflammatory antibiotics such as minocycline
  • If tolerated, careful compression bandaging to reduce swelling

Systemic treatment for larger ulcers due to pyoderma gangrenosum may include:

  • Oral prednisone for several weeks, or intravenous methyl prednisolone for 3–5 days
  • Ciclosporin
  • Anti TNFα inibitor: infliximab, adalimumab or etanercept (off-label)

Other therapies may include:

  • Mycophenolate mofetil
  • Dapsone
  • Potassium iodide solution
  • Methotrexate
  • Cyclophosphamide
  • Intravenous immunoglobulins and plasmapheresis

Outlook or prognosis for pyoderma gangrenosum is unpredictable.

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Steatocystoma Multiplex

What is steatocystoma multiplex?

Steatocystoma multiplex is a rare inherited disorder in which numerous cysts develop at puberty. The lesions have been described as hamartomatous malformations of the pilosebaceous duct junction (hair follicle unit).

If a single cyst of this type is found, it is called steatocystoma simplex.

What are the clinical features of steatocystoma multiplex?

In steatocystoma multiplex, the tendency to develop cysts is inherited in an autosomal dominant fashion, so one parent can be expected to also have steatocystoma multiplex. It may also occur sporadically. Both males and females may be affected.

The onset at puberty is presumably due to hormonal stimulus of the pilosebaceous unit. They most often arise on the chest and may also occur on the abdomen, upper arms, armpits and face. In some cases cysts may develop all over the body.

The cysts are mostly small (2-20 mm) but they may be several centimetres in diameter. They tend to be soft to firm semi-translucent bumps, and contain an oily, yellow liquid. Sometimes a small central punctum can be identified and they may contain one or more hairs (eruptive vellus hair cysts). They may become inflamed and heal with scarring, like acne nodules (see nodulocystic acne and hidradenitis suppurativa).

Steatocystomas are thought to come from an abnormal lining of the passageway to the oil glands (sebaceous duct).

Localised, generalised, facial, acral, and suppurative types of steatocystoma multiplex have been described.

What is the cause of steatocystoma multiplex?

Familial steatocystoma multiplex is associated with mutations in the keratin 17 gene (K17). This gene is responsible for a keratin protein found in the nail bed, hair follicles and sebaceous glands. Mutations in K17 may also result in one form of pachyonychia congenita, in which cysts, plantar keratoderma and natal teeth are common.

What is the treatment for steatocystoma multiplex?

  • Individual cysts can be removed surgically. In most cases, small incisions (cuts into the skin) allow the cyst and its contents to be extracted through the opening. If it is tethered to the underlying skin, excision biopsy may be necessary.


  • Cysts can also be removed by laser, electrosurgery or cryotherapy.
  • Inflammation can be reduced with oral antibiotics
  • Oral isotretinoin is not curative but may temporarily shrink the cysts and reduce inflammation.

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