Detection of Human Papillomavirus Type 39 in a Seborrheic Inclusion Cyst of the Buttock

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/ by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. A seborrheic inclusion cyst (SIC) is a lesion, which has been described as a combination of seborrheic keratosis and an epi-dermoid cyst (EC). To the best of our knowledge, only eight cases of SIC have been reported thus far in the English literature. Microscopically, SICs exhibit features that are suggestive of viral infection. 4 Therefore, an association between SICs and human papillomavirus (HPV) has been suspected, but it has only been demonstrated in one previous report by Terada, 1 which identified an HPV-positive SIC through immunohistochemical staining for HPV antigens. However, no SIC study has ever used HPV genotyping. Herein, we report the first case of SIC associated with HPV type 39, which we identified using the HPV DNA chip. A 21-year-old Korean man presenting with a subcutaneous mass in the left buttock was admitted to the Armed Forces Capital Hospital. An excisional biopsy of the lesion was performed, and gross examination of skin tissue revealed a 2 cm unilocular cyst that was filled with a soft, yellow substance. Microscopic examination of the lesion identified a cyst containing keratins (Fig. 1A). Approximately one half of the cyst exhibited features of a dermoid cyst with a mature squamous epithelium with granular layers and small clusters of sebaceous cells (Fig. 1D), while the other half demonstrated basaloid cell proliferation and pseudohorn cysts (Fig. 1B). In addition, squamous eddies, vacuolated cells and parakeratosis were observed in the cyst wall (Fig. 1C). No significant area of inflammation as might be present in a foreign body reaction was observed in the adjacent soft tissue. There was also no evidence of viral infection, such as vac-uolated cells or parakeratosis, at the skin surface. HPV detection and genotyping were performed using the commercial HPV Genotyping Chip Kit provided by the Bio-medlab Company (Seoul, Korea). DNA was isolated from the paraffin-embedded tissue using the DNA extraction kit that was supplied as a component of the HPV Genotyping Kit. Target HPV DNA and beta globin (as an internal control) were amplified by polymerase chain reaction (PCR) and labeled with cyanine 3 for signal detection. The amplified cyanine 3-labeled products were mixed with a hybridization buffer and applied to the DNA chip. Hybridization …