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Keratinization of the adult male foreskin and implications for male circumcision

Gray, Ron Ha; Bailey, Robert Cb; Morris, Brian Jc

doi: 10.1097/QAD.0b013e3283392555

aJohn's Hopkins University, Bloomberg School of Public Health, Baltimore, Maryland, USA

bUniversity of Illinois at Chicago School of Public Health, Chicago Illinois, USA

cSchool of Medical Sciences, University of Sydney, Sydney, New South Wales, Australia.

Received 2 February, 2010

Accepted 26 February, 2010

Correspondence to Ronald H. Gray, E4132, Johns Hopkins University, Bloomberg School of Public Health, 615 N Wolfe Street, Baltimore, MD 21205, USA. Tel: +1 410 955 7818; fax: +1 410 614 7386; e-mail:

Dinh et al. [1] assessed keratin thickness of the outer and inner surface of the foreskin in 16 men having elective surgery for unknown medical indications, and concluded that there was no difference in keratin thickness between the inner and outer surfaces. They speculate that thinner keratinization of the foreskin inner mucosa does not account for the vulnerability of the foreskin to HIV infection and does not contribute to the efficacy of male circumcision for HIV prevention.

We have reservations about these findings and conclusions. First, these men received circumcision for unknown medical indications and are thus unrepresentative of the majority of uncircumcised men who do not experience pathology requiring surgery. The preceding pathology (e.g. balanitis, phimosis or other infections) may affect the thickness of the keratin layer, this could seriously bias the findings. Second, only one histological section was assessed per participant. The authors do not state the dimensions of each section nor whether the tissue examined was from the proximal or distal foreskin. This could make a substantial difference because naked eye examination of the retracted foreskin suggests a qualitative difference in the appearance of the inner surface mucosa; it is thinner close to the base at the coronal sulcus than at the distal end. Therefore, the anatomical site of the sections could result in data that are misleading if there was over-representation of more distal tissues.

In summary, as valid data on differences in keratinization between the outer and inner foreskin can only be obtained by assessing samples from men receiving circumcision for personal choice rather than a medical indication, and assessing keratin thickness at multiple sites of the distal and proximal foreskin, a conclusion that there is no difference in keratinization between the inner and outer foreskin surface is premature. More research is clearly needed to address this issue in order to better understand the mechanisms whereby circumcision protects men from HIV infection.

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1. Dinh MH, McRaven MD, Kelley Z, Penugonda S, Hope TJ. Keratinization of the adult male foreskin and implications for male circumcision. AIDS 2010; 24:899–906.
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