Concurrent occurrence of Seborrheic Keratosis and Melanocytic Nevus in the same lesion

Abstract

Seborrheic keratosis (SK) is common benign epithelial tumor of the skin that can be associated with other cutaneous tumors such as basal cell carcinoma, squamous cell carcinoma and melanoma. On the other hand, melanocytic nevus (MN) is another very common disease, showing anecdotal association with other cutaneous tumors such as trichoepithelioma, syringoma, basal cell carcinoma, trichilemmal cyst and epidermoid cyst. Although it has recently been reported that somatic mutation of BRAF gene is implicated in MN quite frequently, their pathogenic mechanisms, especially the association with other cutaneous tumors, are still elusive. Despite the high frequency of both tumors, however, collision tumors of SK and MN are extremely rare that only a few case reports have been documented so far. Hereby, we report five cases of simultaneous occurrence of SK and MN in 14-year-old female, 36-year-old female, 39-year-old female, 58-year-old male, and 62-year-old male patients. Additional molecular tests for BRAF mutation (V600E) on micro-dissected tissue of the 58-year-old man revealed positivity on the MN and negativity on the SK. Although these results cannot give direct evidence that both tumors have different pathogenic mechanisms, it seems to be more relevant that these collision tumors may occur by chance.

Keywords

• seborrheic keratosis
• intradermal nevus
• skin neoplasms