CPD Article | EQUINE
•
•
•
•
•
with gray scaly surface. Hair color variation may
be detected.
May increase, or remain static for months or years.
Superficial layers of dermis only.
May → verrucose, nodular or fibroblastic forms,
especially if traumatized.
Some gradually develop increasing numbers
of nodules or areas of hyperkeratinization →
verrucose.
If abraded, these may develop into aggressive
fibroblastic forms.
Type II - Verrucose (warty) sarcoid
• Increased dermal component.
• ‘Warty’ appearance - often over large areas that
start roughly circular but which gradually become
less well defined.
• Obvious, irregular flat areas of hyperkeratosis
with marked skin thickening, variable degrees of
flaking/scaling.
• Hyperkeratosis variable, less pronounced in thin
skinned areas, eg periorbital and facial areas.
• Sessile, broad based or pedunculated.
• Slow growing - but may become more
aggressive after trauma or surgical interference
granulomatous and develop an aggressive
fibroblastic appearance.
• Most common sites include the face, body, groin/
sheath and axillary areas.
Type III - Nodular sarcoid
• Entirely subcutaneous.
• Dense, often spherical nodules under skin of 5-20
mm diameter, but can be larger.
• Overlying skin normal or may be thinner and
shiny, nodule usually mobile (type A nodules).
• Sometimes there are dermal and deep attachments
preventing movement of overlying skin and/or
tumor mass (type B nodules).
• Occasionally erupt through skin → fibroblastic
appearance.
• Thin skinned areas typically, paragenital, face, lips
and eyelids.
• Generally more benign and may be more amenable
to surgical excision.
• Dense appearance (fibroma durum) with well
demarcated edge on section:
○ ○ Type A: these nodules have no cutaneous
involvement - the skin can be moved over the
nodule independently. There is (at least until the
advanced stages when the nodule is very large)
no surface skin change and no alopecia. Later
the skin may become atrophied and glabrous:
- -
Subtype A1: in addition to no skin
involvement there is no deep tissue
involvement - the nodule moves
independently of both the skin and the
deeper tissues. Most of these lesions have
a loose fibrocellular capsule. This type is
usually amenable to surgery under very
particular caveats.
- - Subype A2: the nodule is bound down
to the deeper subcutaneous structures so
that it cannot be moved independently
of them. This usually means that there is
either no fibrocellular capsule or that it is
incomplete. This type may be amenable to
ligation but is probably not amenable to
topical therapy.
○ ○ Type B: the nodule involves the skin often with
overt cutaneous changes such as hair loss,
hyperkeratosis and in some cases ulceration.
The skin moves with the nodule:
- - Subtype B1: the nodule has no deep
tissue involvement and is restricted to the
subcutis. The nodule (and the attached skin
will move together freely over the deeper
• Volume 21 Issue 3 | September 2019 •
33