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1. DERMOSCOPIC FINDINGS OF
POROKERATOSIS
Dr. Usha Chandra

2. • Porokeratosis is a clonal disorder of
keratinization .
• It is characterized by one or more atrophic
patches surrounded by a clinically and
histologically distinctive hyperkeratotic ridge like
border called the cornoid lamella.

3. Histological features

4. • Dermoscopy shows "white track"
structure corresponds to the cornoid lamella
with a brown pigmentation visible in the inside
of the track.

5. • In the central part of the lesion, dermoscopy
may feature a white area, red dots, globules
and lines corresponding to vessels.

6. DERMOSCOPIC FINDINGS OF
DOWLING DEGOS DISEASE

7. • Dowling Degos disease (DDD) also known as
reticular pigmented anomaly of the flexures.
• Autosomal dominant genodermatosis with
variable penetrance due to loss of function
mutations in the keratin 5 gene

8. • It is characterized by slowly progressing
hyperpigmented macules which begins in adult
life and involves predominantly the flexures.

9. • Additional features include follicular
hyperkeratotic papules and pitted perioral
scars.
• Association of dyschromatosis universalis
hereditaria (DUH) like hypopigmented
macules along with the hyperpigmented
macules of DDD has also been reported.

10. • BiOPSY-
• Antler-like filiform elongation of rete ridges .
• Concentration of melanin at the tips with few
dermal melanophages and mild perivascular
lymphohistiocytic infiltrate.
• Follicular plugging and inclusion cysts were also
found in a few areas

11. • Dermatoscopy shows:
• (a) Follicular pits
• (b) Irregular brownish projections (red
arrowhead) around hypopigmented centre
(yellow asterisk)

12. • Dermatoscopy of palmar pit with keratinous
plugging: (a) White light, (b) polarized light