Seborrheic keratoses

Seborrheic keratoses (SK) :
It's a benign epidermal tumour.
It is commonly present in old age.
It's types:
1) Common seborrheic keratoses
2) Skin tags
3) Irritant SK
4) Pigmented SK
5) SK with squamous atypia
6) Stucco keratoses
7) Leser trelat sign
8) Reticulated SK
9) Dermatosis papulosa Nigra (DPN)
10) Clonal SK

Histopathology:
Acanthosis, papillomatosis, pseudo cyst formation, hyper keratosis.

Clinical features:
Stuck on appearance of lesion

Treatment:
Cryotherapy
Electric desiccation
Laser
Surgical excision
Topical flurouracil

Biopsy is recommended when
Rapid growth of lesion
Atypical clinical appearance
Symptomatology
Unusual lesion location
In the above features there is risk of malignant transformation.

Irritant SK may develop in patients who are on chemotherapy especially cytarabine drug.

Lesar Trelat sign:
Eruption of SK on trunk in Christmas tree pattern
Cause: underlying adenocarcinoma of stomach most commonly
Other: adenocarcinoma of lung and colon.

DPN :
Present in skin type 4 and above.

    Fig: seborrhoeic keratoses 

Fig:Leser trelat sign