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<front>
<journal-meta>
<journal-id journal-id-type="publisher-id">KJIM</journal-id>
<journal-title-group>
<journal-title>The Korean Journal of Internal Medicine</journal-title><abbrev-journal-title>Korean J Intern Med</abbrev-journal-title></journal-title-group>
<issn pub-type="ppub">1226-3303</issn>
<issn pub-type="epub">2005-6648</issn>
<publisher>
<publisher-name>The Korean Association of Internal Medicine</publisher-name></publisher></journal-meta>
<article-meta>
<article-id pub-id-type="doi">10.3904/kjim.2019.326</article-id>
<article-id pub-id-type="publisher-id">kjim-2019-326</article-id>
<article-categories>
<subj-group>
<subject>Correspondence</subject></subj-group></article-categories>
<title-group>
<article-title>Comment on &#x0201c;Birt-Hogg-Dub&#x000e9; syndrome in Korean: clinicoradiologic features and long term follow-up&#x0201d;</article-title>
</title-group>
<contrib-group>
<contrib contrib-type="author">
<name><surname>Chang</surname><given-names>Hua-Ching</given-names></name>
<xref ref-type="aff" rid="af1-kjim-2019-326"><sup>1</sup></xref>
</contrib>
<contrib contrib-type="author">
<name><surname>Sung</surname><given-names>Chih-Wei</given-names></name>
<xref ref-type="aff" rid="af2-kjim-2019-326"><sup>2</sup></xref>
</contrib>
<contrib contrib-type="author">
<contrib-id contrib-id-type="orcid">http://orcid.org/0000-0002-9413-9876</contrib-id>
<name><surname>Chou</surname><given-names>Pai-Chien</given-names></name>
<xref ref-type="corresp" rid="c1-kjim-2019-326"/>
<xref ref-type="aff" rid="af3-kjim-2019-326"><sup>3</sup></xref>
<xref ref-type="aff" rid="af4-kjim-2019-326"><sup>4</sup></xref>
</contrib>
<aff id="af1-kjim-2019-326">
<label>1</label>Department of Dermatology, Taipei Medical University Hospital, Taipei, Taiwan</aff>
<aff id="af2-kjim-2019-326">
<label>2</label>Department of Emergency Medicine, National Taiwan University Hospital Hsin-Chu Branch, Hsinchu, Taiwan</aff>
<aff id="af3-kjim-2019-326">
<label>3</label>Division of Pulmonary Medicine, Department of Internal Medicine, Taipei Medical University Hospital, Taipei, Taiwan</aff>
<aff id="af4-kjim-2019-326">
<label>4</label>Division of Thoracic Medicine, Department of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan</aff>
</contrib-group>
<author-notes>
<corresp id="c1-kjim-2019-326">Correspondence to Pai-Chien Chou, M.D. Division of Pulmonary Medicine, Department of Internal Medicine, Taipei Medical University Hospital, No. 252, Wuxing St, Xinyi District, Taipei City 110, Taiwan Tel: +886-2-27372181 Fax: +886-2-23787139 E-mail: <email>baechainchou@gmail.com</email></corresp>
</author-notes>
<pub-date pub-type="ppub">
<month>3</month>
<year>2020</year></pub-date>
<pub-date pub-type="epub">
<day>30</day>
<month>1</month>
<year>2020</year></pub-date>
<volume>35</volume>
<issue>2</issue>
<fpage>474</fpage>
<lpage>475</lpage>
<history>
<date date-type="received">
<day>1</day>
<month>10</month>
<year>2019</year></date>
<date date-type="accepted">
<day>20</day>
<month>12</month>
<year>2019</year></date>
</history>
<permissions>
<copyright-statement>Copyright &#x000A9; 2020 The Korean Association of Internal Medicine</copyright-statement>
<copyright-year>2020</copyright-year>
<license>
<license-p>This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (<ext-link ext-link-type="uri" xlink:href="http://creativecommons.org/licenses/by-nc/4.0/">http://creativecommons.org/licenses/by-nc/4.0/</ext-link>) which permits unrestricted noncommercial use, distribution, and reproduction in any medium, provided the original work is properly cited.</license-p></license></permissions>
<related-article related-article-type="commentary-article" id="kjim-2019-326" vol="34" page="830" ext-link-type="pmc"/>
</article-meta></front>
<body>
<p>We read with interest the research published by Lee et al. &#x0005b;<xref ref-type="bibr" rid="b1-kjim-2019-326">1</xref>&#x0005d; in the Korean Journal of Internal Medicine in July 2019 regarding clinicoradiologic features in Korean patients with Birt-Hogg-Dub&#x000e9; (BHD) syndrome. We appreciate the fact that this case series involving 12 Korean patients with BHD syndrome presented characteristics of a higher risk of pneumothorax and less frequent skin lesions compared with previous reports. Skin lesions are the common features and one of the major diagnostic criteria for BHD syndrome, and they usually appear as multiple papules on the face after the age of 20 years. Histologically, the skin tumors are fibrofolliculomas or trichodiscomas &#x0005b;<xref ref-type="bibr" rid="b2-kjim-2019-326">2</xref>&#x0005d;. Noticeably, in the Introduction section, Lee et al. &#x0005b;<xref ref-type="bibr" rid="b1-kjim-2019-326">1</xref>&#x0005d; cited two articles on Japanese patients with BHD syndrome who presented a lower incidence of skin lesions than Caucasian patients &#x0005b;<xref ref-type="bibr" rid="b3-kjim-2019-326">3</xref>,<xref ref-type="bibr" rid="b4-kjim-2019-326">4</xref>&#x0005d;. However, we observed an unintentional mistake by the authors in the presentation and interpretation of data from the original studies. We adjusted the descriptions of these data in different ways. In a study by Kunogi et al. &#x0005b;<xref ref-type="bibr" rid="b3-kjim-2019-326">3</xref>&#x0005d;, skin lesions were detected in seven out of 30 patients with BHD syndrome (7/30, 23.3%), and fibrofolliculomas were diagnosed in one patient among only two patients undergoing biopsy (1/2, 50%). In another study by Furuya et al. &#x0005b;<xref ref-type="bibr" rid="b4-kjim-2019-326">4</xref>&#x0005d;, 76 individuals among 156 folliculin mutation carriers reported skin lesions (76/156, 48.7%), but fibrofolliculomas were diagnosed only in six patients from 28 biopsied skin tissues (6/28, 21.4%). These corrected values were still consistent with the relatively lower incidence of skin lesions in Japanese patients. By contrast, one recent study by Iwabuchi et al. &#x0005b;<xref ref-type="bibr" rid="b5-kjim-2019-326">5</xref>&#x0005d; in Japan reported a relatively higher incidence of skin lesions in patients with BHD syndrome (26/31, 83.9%) and a high percentage of tissue-proved fibrofolliculomas and/or trichodiscomas (17/23, 73.9%). The reasons for the high variations in these case series may be attributed to differences in inclusion criteria, possible selection bias, and lack of perception to identify relatively unremarkable skin lesions among Asians. Larger future cohort studies are warranted to obtain more precise data on the prevalence and features of skin lesions in Asian patients with BHD syndrome.</p>
</body>
<back>
<fn-group>
<fn fn-type="conflict"><p>No potential conflict of interest relevant to this article was reported.</p></fn>
</fn-group>
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