Authors: Claire Jordan Wiggins, Riyad N.H. Seervai, Medical Students, Baylor College of Medicine, Houston, Texas, USA. DermNet Editor in Chief: Adjunct A/Prof Amanda Oakley, Dermatologist, Hamilton, New Zealand. Copy edited by Gus Mitchell. April 2020.
Tuberous sclerosis is a neurocutaneousautosomal dominant syndrome, in which angiofibromas appear in childhood in the nasolabial folds and on the central face [2]. Patients with tuberous sclerosis commonly develop an oral fibroma or a periungal angiofibroma (Koenen tumour) over time [1]. The facial angiofibromas associated with tuberous sclerosis are also called adenoma sebaceum, juvenile angiofibroma, and Pringle tumour.
Angiofibromas in tuberous sclerosis
Angiofibromas in tuberous sclerosis
Angiofibromas in tuberous sclerosis
Birt-Hogg-Dubé syndrome
Facial angiofibromas have been reported in Birt-Hogg-Dubé syndrome, a rare genodermatosis characterised by skin and renaltumours, as well as spontaneous pneumothorax [3]. Most of the cutaneous lesions however are fibrofolliculomas, which are abnormal growths of the hairfollicles.
Multiple endocrine neoplasia type 1
Multiple endocrine neoplasia type 1 is a hereditary syndrome that leads to tumours in several endocrine organs [1].
Acquired angiofibroma
Angiofibromas can also be acquired and unrelated to a genetic syndrome, commonly in the form of:
A fibrous papule is characteristically found in adults as a solitary lesion usually on the nose, often clinically mistaken for a basal cell carcinoma or melanocytic naevus. It is thought to be a form of dermal naevus.
Multiple pearly penile papules occur in 10–30% of adult males on the coronal edge and sulcus. They can be mistaken for viral warts [1,2].
Angiofibromas are caused by a local overgrowth of collagen, fibroblasts, and blood vessels.
In tuberous sclerosis, mutations are present in tuberous sclerosis complex 1 (TSC1), which encodes the protein hamartin, and tuberous sclerosis complex 2 (TSC2) which encodes the protein tuberin.
Birt-Hogg-Dubé syndrome is due to a mutated FLCNgene, which encodes the protein folliculin [3].
Multiple endocrine neoplasia type 1 results from a mutation in the MEN1 gene which produces the protein menin [1].
Genetic mosaicism for these genetic conditions must also be considered [4]. What specifically triggers the development of angiofibroma is unknown.
What are the clinical features of angiofibroma?
An angiofibroma is a firm, flesh-coloured dome-shaped papule less than 5 mm in diameter. Small capillaries may be visible on the surface of the lesion.
Facial angiomas associated with a genetic syndrome are commonly found in clusters in the butterfly region of the face.
A fibrous papule of the face is usually a solitary lesion located on the nose in an adult.
Pearly penile papules are 1–3 mm skin coloured or white papules in a row along the penile coronal margin [5].
What are the complications of angiofibromas?
Angiofibromas may be itchy and may also bleed. Those associated with genetic syndromes result in facial disfigurement and stigmatisation [1]. See Psychosocial factors in dermatology.
How are angiofibromas diagnosed?
The diagnosis of angiofibroma may be made clinically or after a skin biopsy. The histopathology of angiofibroma shows an ‘onion skin’ pattern around vessels and follicles, hyperkeratosis, and vascular proliferation [5].
If an underlying genetic condition is suspected, appropriate genetic screening and evaluation are required [1].
What is the differential diagnosis for angiofibromas?
The differential diagnosis for angiofibroma depends on its location [1].
Differential diagnoses for facial lesions that can resemble angiofibromas can include:
Although angiofibromas are benign, they are persistent. Angiofibromas can be removed for cosmetic or pain-related reasons. The recurrence rate for angiofibromas associated with tuberous sclerosis may be as high as 80% [1].