FIbroblastic neoplasms

Question 1

Acrochordons
(skin tags)

Associations

Answer 1

Diabete Mellitus
Obesity

Birt Hogge Dube
Cowdens sydrome

Question 2

Acrochordons Rx
(skin tags)

Answer 2

Not required

Scissor excision
Cryotherapy
Currette etc

Ablative laser

Question 3

Describe and DDx

Answer 3

Solitary, dome shaped, and shiny skin coloured to reddish papule located on the nose.

Fibrous papule / anigiofibroma

BCC
Intradermal naevus

Question 4

Cause of multiple facial angiofibromas

Answer 4

Tuberosclerosis
MEN type 1
Birt Hogg Dube

Rarely - NF2

Question 5

Histology of an angiofibroma

Answer 5

Dome shaped lesions with dermal proliferation of plump or stellate fibroblasts in a collagenous stroma with an increase in the number of thin-walled, dilated blood vessels

Question 6

Dx

Answer 6

Angiofibroma

Question 7

Families with inherited multiple DF have mutations in ?

What is the inheritance?

Answer 7

autosomal dominant

Factor 13A1

Question 8

Clinical features of a dermatofibroma

Answer 8

• Occur mainly in adults and often develop on the lower extremities
• Firm, minimally elevated to dome shaped papules which are <1cm in diameter, but occasionally are >2cm
• Hyperpigmented often
• Pinching the lesion results in an apparent downward movement of the tumour also known as the dimple sign
• Dermoscopically – central white scar like patch or white network surrounded by a delicate pigment network

Question 9

Multiple eruptive DF can be seen in

Answer 9

autoimmune disorders (SLE),
atopic dermatitis and
immunosuppression (HIV infection)

Question 10

Immunohistochemistry of a dermatofibroma

Answer 10

vimentin +,
factor 13 a+,
muscle specific actin +,
CD68 +

Negative for CD34 (in the centre of the lesion) - DFSP is diffusely positive

Question 11

Histological variants of a dermatopfibroma

Answer 11

Aneurysmal fibrous histiocytoma – can metastasise

Atypical – monster cells – can metastasise
Balloon cell

Clear cell

Cellular DF – can metastasise

Deep DF with atypical cells – can mimic DFSP

Epithelioid fibrous histiocytoma

Granular cell DF

Haemosiderotic DF

Lipidised fibrous histiocytoma

Myxoid

Myoid fibroma

Metastasising fibrous histiocytoma

Palisading DF

Xanthomatous DF

Question 12

Dx

Answer 12

Dimple sign

Suggestive of a dermatofibroma

Question 13

Histology of a dermatofibroma

Answer 13

Induction of the epidermis - “tabling”

Spindle cell proliferation in the dermis
- haphazard
- jaggered edges (not smooth borders)
- entraps collagen bundles at the periphery

Can have haemosiderin staing, can have foamy or vacuolated appearance (xanthomatous) cytoplasm

Question 14

What is this?

Answer 14

Solitary, skin coloured to pink, slightly keratotic, exophytic papulonodules with a collarette of elevated skin

Acral fibrokeratoma