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Background Polydeoxyribonucleotide (PDRN) influencing cellular growth and differentiation is recognized to promote wound healing by stimulating tissue repair. Although PDRN can be extracted from human placentas, PDRN medications have recently been extracted from the semen of trout (Oncorhynchus mykiss) and salmon (Oncorhynchus keta). The present study was designed to evaluate the wound healing effects of O. keta-derived PDRN for injection (Rejuvenex) and PDRN cream (Rejuvenex Cream) in comparison with those of O. mykiss-derived PDRN injection (Placentex).Methods Full-thickness skin defects were made on the back of mice (n=60). The mice were divided into the following four groups according to the dressing used for the wounds: O. mykiss-derived PDRN injection group, O. keta-derived PDRN injection group, O. keta-derived PDRN cream group, and normal saline soaked dressing group (control group). We analyzed the gross findings, wound sizes, histological findings, immunohistochemistry and enzyme-linked immunosorbent assays for the groups immediately after the treatment, and again after 4, 7, and 10 days of treatment.Results The wound healing effects were the greatest in the O. keta-derived PDRN injection and O. mykiss-derived PDRN injection groups, which showed similar scores, followed by the O. keta-derived cream and normal saline soaked dressing groups.ConclusionThe injection of PDRN extracted from O. keta was found to be as effective at healing full-thickness skin defects as the O. mykiss-derived PDRN injection, which is currently used in the clinic. Moreover, the O. keta-derived PDRN injection was also found to reduce the time required for wound healing.

Chondroid syringoma is a rare mixed tumor of the skin which is composed of both mesenchymal and epithelial cells. Its incidence at less than 0.1% and is frequently located on the head and neck. Chondroid syringoma is easily confused with epidermal cysts. Since malignant forms of chondroid syringoma have been reported, accurate and timely diagnosis is important for proper management. We report clinical and histological features of chondroid syringoma in 5 patients treated at our institution. In most of the cases, chondroid syringoma presented as a round, firm, nodular or cystic lesion that had well marginated heterogeneity in sonography. Clinically, all of the lesions were removed by simple excision. Microscopically, all five tumors were well circumscribed and consisted of epithelial, myoepithelial, and stromal components. The epithelial component formed tubules lined by one or more rows of eosinophilic epithelial cells. The outer layer of tubules appeared to be flattened myoepithelial cells. The stroma is myxoid and contained spindle shaped myoepithelial cells. We expect that the clinical, sonographic, and histological data from our report may help clinicians who are confronted with various kinds of analogous facial lesions to decide the most proper management for their patients.