Chung-Hong Hu

Transdermal drug delivery enhanced and controlled by erbium:YAG laser: a comparative study of lipophilic and hydrophilic drugs

The influence of an erbium:YAG laser on the transdermal delivery of drugs across skin was studied in vitro. Indomethacin and nalbuphine, which have the same molecular weight, were selected as model lipophilic and hydrophilic drugs, respectively, to compare skin permeation by laser treatment. The results indicate a significant increase in the permeation of indomethacin and nalbuphine across skin pretreated with an erbium:YAG laser. The laser had a greater effect on the permeation of hydrophilic molecules which usually possess low permeability. The laser intensity and its spot size were found to play an important role in controlling transdermal delivery of drugs. Permeation of the hydrophilic drug increased following an increase of laser energy. On the other hand, a different result was observed for the lipophilic drug transported across laser-treated skin. The stratum corneum (SC) layer in skin could be partly ablated by the erbium:YAG laser. The barrier function of the SC may also be modulated by a lower intensity of the laser without affecting the viability and structure of the epidermis/dermis as determined by histological observations. However, ultrastructural alteration of the epidermis/dermis may be caused by laser treatment. Use of an erbium:YAG laser is a good method for enhancing transdermal absorption of both lipophilic and hydrophilic drugs, because it allows precise control of SC removal, and this ablation of SC can be reversible to the original normal status.

Coexistence of localized Langerhans cell histiocytosis and cutaneous Rosai-Dorfman disease.

Summary Rosai–Dorfman disease (RDD; sinus histiocytosis with massive lymphadenopathy) and Langerhans cell histiocytosis (LCH) are two different yet pathogenetically related histiocytic disorders. While systemic and localized forms have been identified in both diseases, each has its own characteristic histological, immunohistochemical and ultrastructural profile. Rarely, either RDD or LCH can also occur in the context of certain malignant neoplasms. However, the coexistence of RDD and LCH has never been described. We report a case of cutaneous RDD in which a focus of LCH was found. Clinical and laboratory examinations revealed no evidence of extracutaneous involvement of RDD or LCH. We believe that this is the first report of such a coexistence, and the possible pathogenesis is discussed.

Acrokeratosis paraneoplastica (Bazex syndrome) with adenocarcinoma of the colon: report of a case and review of the literature

Abstract: Acrokeratosis paraneoplastica is a rare disease and is uncommon even in patients with upper aerodigestive tract cancer. We report a 63-year-old man with a 1-month history of numerous pruritic lesions and vesicles on both feet. Although he had received local therapy, progressive dense scale formation involving both palms and both soles was found. Colonoscopy was performed because of hematochezia, and it revealed an early colon cancer. After the resection of the cancer, the skin lesions began to fall off dramatically. To the best of our knowledge, there is no report of acrokeratosis paraneoplastica associated with colon cancer in the literature. This is the first case report of acrokeratosis paraneoplastica associated with early colon cancer.

Milium‐like syringoma: a case study on histogenesis

Background:  Milium‐like syringoma is a variant of syringoma first described in 1987. Only few cases have been reported in the literature. It may be misleading clinically, and its histogenesis has not been clarified.