Cutaneous malignancies simulating seborrheic keratoses: An underappreciated phenomenon?

Area of Science:

• Dermatopathology
• Oncology
• Clinical Diagnosis

Background:

• Seborrheic keratosis (SK) is a common benign skin condition typically diagnosed clinically.
• Variable clinical presentations of SK can lead to suspicion of malignancy, necessitating biopsy.
• Biopsies may also be performed for cosmetic or irritative reasons.

Purpose of the Study:

• To evaluate the diagnostic accuracy of biopsies submitted for suspected seborrheic keratosis.
• To determine the frequency of malignancy in cases clinically diagnosed as SK or irritated SK (ISK).

Main Methods:

• Retrospective analysis of 4361 dermatopathology samples from 2015.
• Inclusion criteria: clinical diagnosis of SK or ISK without other diagnoses or malignancy modifiers.
• Exclusion criteria: cases with modifiers suggesting malignancy (e.g., 'rule out others,' changing, growing).

Main Results:

• 86.2% of biopsies confirmed SK or ISK.
• 10.7% were other benign conditions (e.g., dermatofibroma).
• 3.1% were malignancies, including squamous cell carcinoma (67%), basal cell carcinoma (24.3%), and melanoma (8.8%).

Conclusions:

• Seborrheic keratosis can clinically mimic skin cancer, even in cases without suspicious features.
• A notable percentage of biopsies submitted for presumed SK reveal malignancies.
• Highlights the importance of accurate clinical assessment and histopathological correlation.