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Latest update 16/06/09
This chapter is set out as follows:
Introduction
- The majority of appendageal tumours differentiate towards or arise from either the pilosebaceous apparatus (hair follicle, sebaceous gland and in some body sites the apocrine gland) or the eccrine sweat glands
- The pilosebaceous unit is concentrated in the head and neck area with the pilar element predominant on the scalp and the sebaceous element on the face, chest and upper back areas
- The apocrine sweat glands are mainly found in the axilla, breast and perineal area
- The eccrine sweat glands are found on all body sites
- Classification of appendageal tumours is not always straightforward as the line of differentiation of some tumours can be either apocrine or eccrine
- Appendageal tumours are relatively rare, their clinical appearance is commonly non-specific, and vast majority are not diagnosed until after excision
- The great majority of appendage-derived tumours are relatively benign and although local recurrence is frequently reported, metastases are rare
Malignant appendageal tumours
Such lesions are rare, some of the most noted of these lesions are as follows:
- Sebaceous carcinoma – a solid yellow-orange lesion, often with a translucent appearance. It predominantly affects the eyelids, especially the upper eyelid
- Eccrine gland carcinomas – the most common of this group is the malignant eccrine poroma, which most commonly presents on the lower limbs in older patients
- Apocrine gland carcinomas – these are extremely rare. They present as a non-tender and mobile subcutaneous nodule. Most cases arise in the axilla, but they can also arise in the anogenital area or breast
- Paget’s disease of the nipple – this probably arises from the apocrine duct-derived epithelial cells. It is rare before the fourth decade and most commonly arises in the fifth and sixth decade. Clinical features develop slowly to include crusting and eczematous changes, which are sharply marginated and have an irregular outline. Areas affected include the nipple, areola and in later stages the skin of the breast – change is confined to one breast. Occasionally there may be a blood stained discharge, nipple retraction or a palpable lump
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Figure 1 –Early stage of Paget’s disease of the nipple
(copied with kind permission from Dermatoweb)
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Figure 2 – More advanced Paget’s disease of the nipple
The black ring is from a marker pen
(copied with kind permission from Dermatoweb)
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Figure 3 - Eccrine porocarcinoma
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Figure 4 - Close up of figure 3
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Other appendageal tumours of significance
There are a number of other appendageal tumours of significance, either because they have the potential to become malignant or because they can be associated with underlying systemic disease. Other than the naevus sebaceous these conditions are very rare
- Naevus sebaceous of Jadassohn (syn. sebaceous naevus; organoid naevus) - usually seen at birth on the scalp, and occasionally the face as a slightly raised smooth yellow patch/plaque. They become papillomatous at puberty. A naevus sebaceous can occasionally transform into basal cell carcinoma (BCC) - in the past it was believed that this happened in approximately 4% of cases, however it is now believed that many of the lesions previously diagnosed as BCC where instead trichoblastoma's, which are benign. As a result there is a move away from excising all naevus sebaceous lesions and instead offering watch and wait if the patient chooses to do so
- Syringocystadenoma papilliferum – most arise at birth on the scalp and face. They usually present as a fairly extensive verrucous lesion. As with the above lesions can occasionally transform into BCC
- Muir-Torre syndrome – is a rare autosomal dominant condition. It is diagnosed by a combination of any sebaceous adenomas (in 25-60% of case), epitheliomas, carcinomas or multiple keratocacnthomas PLUS one of the following visceral carcinomas - predominantly colorectal but also gastric, small bowel, endometrial, ovarian, urinary tract and hepatobiliary. All patients found to have any of the listed sebaceous tumours or multiple keratocacanthomas should be referred to a combined dermatology/genetics clinic for further investigations
- Cowden syndrome (syn. multiple hamartoma syndrome) – is an autosomal dominant condition with variable expression. Patients tend to present as young adults with increasing numbers of hair follicle tumours (in particular trichilemmomas) and sometimes oral papillomas. The condition is associated with carcinoma of the breast and thyroid gland
- Gardner syndrome – comprises multiple epidermoid cysts especially of the face and scalp, fibrous tissue tumours, osteomas and polyposis of the colon. Other features include abnormalities of the skull / facial bones and dental problems. Colonic malignancy develops in over 40% of reported cases
- Birt-Hogg-Dube syndrome - comprises multiple fibrofolliculomas over the face, neck and upper trunk along with renal tumours and carcinomas. The skin lesions tend to appear in the 3rd and 4th decade. A history of spontaneous pneumothorax and/or lung cysts supports the diagnosis
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Figure 1 – Sebaceous naevus in a child
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Figure 2 – Sebaceous naevus in an adult
Note the lesions has become thickened / ‘warty’
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Figure 3 – Sebaceous naevus and very early BCC
Sebaceous naevus (black arrow), histology noted very early BCC change in upper portion (purple arrow). On reflection could this have been a trichoblastoma?
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Figure 4 – Sebaceous naevus and a BCC
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Figure 5 – Sebaceous adenoma forehead
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Figure 6 – Sebaceous adenoma left cheek
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Appendageal tumours of limited significance
i) Other sebaceous gland tumours
Sebaceous carcinoma and sebaceous gland tumours of clinical significance (sebaceous adenoma, sebaceous epithelioma) are very uncommon. On the other hand sebaceous gland hyperplasia is very common and has no significant associations
- Sebaceous gland hyperplasia
- Very common and presents in middle-aged and elderly patients
- Mainly found on the foreheads and temples
- Multiple 1-3mm sized yellow papules
- Lesions occasionally misdiagnosed as BCC – if there is any clinical doubt dermoscopy can usually differentiate between the two without the need for a biopsy
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Figure 1 – Sebaceous gland hyperplasia
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Figure 2 – Dermoscopic view of upper lesion figure 1
Dermoscopy shows the ‘cumulus’ sign (multiple white cloud like areas - black arrows)
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ii) Hair follicle tumours
Other than the rare cases of the Muir Torre and Cowden’s syndrome, the vast majority of hair follicle tumour’s have no significant associations
- Pilomatricoma (syn. pilomatixoma)
- The most common hair follicle tumour
- The majority of patients are under 20 when they present
- Distribution - head, neck and upper extremity
- Palpation – a hard, lobular, deep dermal or subcutaneous tumour 3-30mm in size
- Occasionally lesions may arise in older patients when they often grow more rapidly and may occur at atypical sites
- There are many other tumours described including trichoepithelioma, desmoplastic trichoepithelioma, trichofolliculoma, trichodiscoma, firborofolliculoma, inverted follicular keratoses, and tumours of the follicular infundibulum. The lesions are -
- Uncommon
- Mainly present on the face as single or multiple skin coloured papules - they are often only diagnosed after histology
- In soliatry lesions the main differential diagnosis is that of a BCC
- The main problem tends to be that of a cosmetic one
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Figure 1 – Pilomaticoma of dorsum of hand
The lesion grew rapidly in this elderly patient. Given the history and site the lesion was excised for confirmation
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Figure 2 – Dermoscopic appearance of figure 1
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Figure 3 – Trichoepithelioma of the nose (slightly out of focus)
Trichoepithelioma tend to present in young adults as a solitary smooth papule, usually on the face. Less commonly multiple lesions occur, located mainly along the nasolabial folds and other midline areas of the face
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Figure 4 – Trichoepithelioma of the cheek
Solitary lesions can look very much like a BCC and so histology is essential
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Figure 5 – Trichofolliculoma
This lesion lacked the tuft of hair that can be found in trichofolliculoma
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Figure 6 – Trichoadenoma of the scalp
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Figure 7 – Inverted follicular keratosis
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iii) Other apocrine / eccrine gland tumours
Tumours of the apocrine and eccrine sweat glands are relatively uncommon and in some cases the diagnosis may only become apparant with histology
The lists below give a brief description of some of the sweat gland tumours that have been described. The classification between apocrine and eccrine is somewhat arbitary as some lesions can evolve from either line of differentiation
- Apocrine sweat gland tumours
- Apocrine hidrocystoma – this lesion is not uncommon and presents in adults as a solitary translucent papule-nodule, most often close to the eye. The lesion can be skin coloured or blue-black
- Dermal cylindroma – mainly scalp, single or multiple pedunculated, smooth and firm, pink-red nodules. May become very large. A familial autosomal dominant pattern can occur in which patients present with a very large numbers of lesions (‘turban’ tumours)
- Hidradenoma papilliferum – mainly in adult woman, the vulva is the most common site
- Eccrine sweat gland tumours
- Syringoma – multiple flat topped papules around eyes, more common in women
- Chondroid syringoma – subcuateous nodule, head and neck, may be very large
- Hidroacanthoma simplex – usually a facial plaque
- Eccrine poroma – moist, pink elevated lesions, soles of feet
- Eccrine hidrocystoma – similar to apocrine version
- Eccrine spiradenoma – early adult life, painful nodules on any body site
- Eccrine hidradenoma – isolated red or bluish nodule on any body site
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Figure 1 - Cylindoma
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Figure 2 – Eccrine hidrocystoma
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Figure 3 – Eccrine hidradenoma of scalp
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Figure 4 - Spiradenoma
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