Spectrum of seborrheic keratoses in South Indians: a clinical and dermoscopic study.

Background: Even though seborrheic keratoses (SK) have been well characterized clinically and histopathologically, data regarding clinical and dermoscopic correlation of different types of SK are inadequate.

Aims: We carried out a study to establish any correlation between the clinical and dermoscopic appearance of SK and its variants.

Methods: This was a descriptive study conducted in the Department of Dermatology, a tertiary care institute, from August 2008 to June 2010. Patients with SK were evaluated with respect to age, sex, age of onset, duration, site of lesions, number of lesions, and morphology. Dermoscopy was performed in all cases.

Results: A total of 250 cases of SK were recruited. A male-to-female ratio was 1:1.04. The most common age group affected by SK was 60 years and above (40%). The most common clinical variant was common seborrheic keratosis (CSK) (60%). Comedo-like openings (CL) (80%), fissures and ridges (FR) (52%), and sharp demarcation (SD) (83%) were consistent finding on dermoscopy in CSK. Dermatosis papulosa nigra (DPN) and pedunculated seborrheic keratoses (PSK) had characteristic CL and FR in both of them. Fingerprint (FP) (55%) and network-like (NL) (88%) structures were commonly seen in flat SK. Stucco keratoses demonstrated SD (100%) and NL structures (100%).

Conclusions: The most common clinical variant of SK was CSK, followed by DPN, PSK, Flat SK, and stucco keratoses. Dermoscopic findings were consistent with those described in the literature.