Abnormal keratin expression in circumscribed palmar hypokeratosis.
BACKGROUND
Circumscribed palmar or plantar hypokeratosis (CPH) is a rare skin disorder only recently described.


OBJECTIVE
To determine the diagnostic features and to provide insight into the pathogenesis of CPH, with analysis of two new Japanese cases.


METHODS
Dermoscopy, immunohistochemistry, electron microscopy, polymerase chain reaction amplification for human papillomavirus (HPV) DNA and 16S microbial rRNA gene profiling were conducted.


RESULTS
Dermoscopy showed characteristic features using both dry and jelly immersion observation; step-like desquamation and a homogeneous erythema with regularly distributed whitish spots. Immunohistochemistry revealed strong staining with anti-pankeratin antibody (AE1+AE3) and anti-keratin 16 antibody, and decreased expression of keratin 2e. EM revealed a breakage of the corneocytes within their cytoplasm, but structures for cell attachment were intact. HPV and lesion-specific bacteria were not detected.


CONCLUSIONS
The number of cases analyzed was two.


CONCLUSIONS
Hyperproliferative epidermal state along with enhanced corneocyte fragility may account for the unique features in CPH.
Ishiko
Akira
A
Department of Dermatology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku, Tokyo 160-8582, Japan. ishiko@sc.itc.keio.ac.jp
Dekio
Itaru
I
Fujimoto
Atsushi
A
Kameyama
Kaori
K
Sakamoto
Mitsuo
M
Benno
Yoshimi
Y
Amagai
Masayuki
M
Nishikawa
Takeji
T
D000368:Aged; D001419:Bacteria / Q000235:genetics; D004279:DNA, Viral / Q000032:analysis; D005260:Female; D006229:Hand Dermatoses / Q000378:metabolism* / Q000382:microbiology / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D053557:Keratin-2 / Q000378:metabolism*; D007633:Keratins / Q000378:metabolism*; D007642:Keratosis / Q000378:metabolism* / Q000382:microbiology / Q000473:pathology; D008854:Microscopy, Electron; D008875:Middle Aged; D027383:Papillomaviridae / Q000235:genetics; D012150:Polymorphism, Restriction Fragment Length; D012336:RNA, Ribosomal, 16S / Q000032:analysis; D013194:Staining and Labeling
D004279:DNA, Viral; D053557:Keratin-2; D012336:RNA, Ribosomal, 16S; D007633:Keratins