Y5 - Benign skin lesions (incl. dermatofibroma, seborrhoeic keratoses) Flashcards
def of dermatofibroma
benign skin growth
dermatofibroma is AKA
benign fibrous histiocytomas
signs and symptoms of BFH
hard solitary slow-growing papules (rounded bumps)
usually nothing, but sometimes itching and tenderness
what colour are BFH
tanned/brownish colour
what sign is BFH associated with
dimple sign
what is dimple sign
applying lateral pressure causes a central depression of the dermatofibroma
where are dermatofibromas most commonly found
on the legs and arms
epi of BFH
women>men
young adults
aetiology of BFH
possibly related to previous injuries (insect bites or thorn pricks)
causing disordered collagen to be laid down by fibroblasts
what is the positive buttonhold sign
central dimpling in the center of BFH
what are dermatofibromas
positive for stromelysin-3, and factor XIIIa
management for BFH
usually none
prognosis of BFH
excellent
some may suffer from pain or itching
physical examination of a BFH
solitary <1cm nodule
def of SK
a common, multiple, benign skin tumour
where is SK commonly found
on the torso
epi of SK
middle age
vvv common
what do SK look like
circumscribed grey/brown/black plaques with a stuck on appearance
aetiology of SK
clonal expansion of mutated epidermal keratinocytes by unknown cause
possibly associated with chronic UV damage
what mutations are involved in SK
FGFR3 mutations
signs and symptoms of SK
- ‘stuck on’ lesions
- on face or torso
- yellow-dark brown
- slightly raised lesion with a wart like texture
RFs of SK
older
white
FHx
investigations of SK
dermoscopy
-milia-like cysts and comedo-like openings
biopsy and histopathological examination
-sharply defined exophytic lesions
management of SK
for itchy lesions -corticosteroids (betamethasone) for raised SK -curretage or cautery for flat SK -cryotherapy
