Ann Dermatol Vol. 24, No. 2, 2012 CASE REPORT Granular Parakeratosis of Eccrine Ostia http://dx.doi.org/10.5021/ad.2012.24.2.203 Granular Parakeratosis of Eccrine Ostia Ji-Hye Yang, M.D., Hyung-Min Lee, M.D., Tai-Kyung Noh, M.D., Chong-Hyun Won, M.D., Sungeun Chang, M.D., Mi-Woo Lee, M.D., Jee-Ho Choi, M.D., Kee-Chan Moon, M.D. Department of Dermatology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea Granular parakeratosis is a recently recognized disorder of keratinization that is usually confined to intertriginous areas. The histopathologic features are distinctive and diagnostic. Rarely, histopathologic variants such as follicular granular parakeratosis and granular parakeratosis of eccrine ostia have been described. In this report, we describe a rare case of granular parakeratosis mostly confined to eccrine ostia. (Ann Dermatol 24(2) 203∼205, 2012) -Keywords- Eccrine glands, Neck, Parakeratosis INTRODUCTION Granular parakeratosis is an uncommon acquired disorder of keratinization. It is characterized by keratotic papules or plaques that are located in the intertriginous areas. Histo- pathologic features consist of hyperkeratosis, parakera- tosis, and retention of keratohyaline granules in the stratum corneum. Until now, only one case of granular para- keratosis confined to the eccrine ostia has been reported1. We describe a rare case of granular parakeratosis that mostly affected the eccrine ostia. Received January 5, 2011, Revised March 23, 2011, Accepted for publication April 5, 2011 Corresponding author: Mi-Woo Lee, M.D., Department of Dermatology, Asan Medical Center, University of Ulsan College of Medicine, 388-1 Pungnap-dong, Songpa-gu, Seoul 138-736, Korea. Tel: 82-2-3010- 3460, Fax: 82-2-486-7831, E-mail: miumiu@amc.seoul.kr 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. CASE REPORT A 60-year-old female patient visited our clinic in August with a 15-year history of multiple brownish verrucous papules on her neck (Fig. 1A). She reported that each year these lesions appear in the spring, became more aggravated in the summer and resolved spontaneously in the fall or winter. Moreover, these lesions worsened when the patient was exposed to a hot environment, such as a sauna. Because the patient became hot easily and sweated profusely, especially on the neck, she regarded the lesions as a heat rash. Applications of topical steroids and antiperspirants, however, were ineffective. While sweating, the patient felt a burning sensation in the area around the lesions. A biopsy specimen of the papules revealed hyper- keratosis and prominent parakeratosis of the stratum corneum (Fig. 2A). High power resolution showed that the parakeratotic corneocytes contained basophilic granules similar to keratohyaline granules of the stratum granu- losum (Fig. 2B). These changes were especially prominent around the eccrine ostia. The cutaneous lesions of our patient resolved spontaneously as the climate became cooler, and cleared completely when the patient revisited our clinic in October (Fig. 1B). DISCUSSION Granular parakeratosis is a rare benign disorder initially described by Northcutt et al.2 in 1991, who used the term “axillary granular parakeratosis”. Women are affected more commonly than men3. It usually occurs during middle-age, but may also be observed in children4. Granular parakeratosis usually presents as hyperkeratotic papules or plaques on skin folds, including the axilla, groin, and mammary crease. It sometimes occurs on the abdomen or lumbosacral area. Although the etiology of granular parakeratosis is un- known, it may be associated with contact reactions to Vol. 24, No. 2, 2012 203