Je-Won Seo

In vivo cartilage formation using chondrogenic-differentiated human adipose-derived mesenchymal stem cells mixed with fibrin glue.

Human adipose-derived mesenchymal stem cells (MSCs) were differentiated into chondrogenic MSCs, and fibrin glue was used together to explore the feasibility of whether cartilages can be generated in vivo by injecting the differentiated cells. Mesenchymal stem cells extracted from human adipose were differentiated into chondrogenic MSCs, and such differentiated cells mixed with fibrin glue were injected subcutaneously into the back of the nude mouse. In addition to visual evaluation of the tissues formed after 4, 8, and 12 weeks, hematoxylin-eosin staining, Masson trichrome staining, measurement of glycosaminoglycan concentration using dimethylmethylene blue, agreecan through reverse transcriptase-polymerase chain reaction, type II collagen, and expression of SOX-9 were verified. Moreover, the results were compared with 2 groups of controls: 1 control group that received only injection of chondrogenic-differentiated MSC and the supporting control group that received only fibrin glue injection. For the experimental group, cartilage-like tissues were formed after 4, 8, and 12 weeks. Formation of cartilage tissues was not observed in any of 4, 8, and 12 weeks of the control group. The supporting control group had only a small structure formation after 4 weeks, but the formed structure was completely decomposed by the 8th and 12th weeks. The range of staining dramatically increased with time at 4, 8, and 12 weeks in Masson trichrome staining. The concentration of glycosaminoglycan also increased with time. The increased level was statistically significant with more than 3 times more after 8 weeks compared with 4 weeks and more than 2 times more after 12 weeks compared with 8 weeks. Also, in reverse transcriptase-polymerase chain reaction at 4, 8, and 12 weeks, all results expressed a cartilage-specific gene called aggrecan, type II collagen, and SOX-9. The study verified that the chondrogenic-differentiated MSCs derived from human adipose tissues with fibrin glue can proliferate and form new cartilage. Our findings suggest that formation of cartilages in vivo is possible.

Pleomorphic adenoma in the auricle.

Pleomorphic adenoma (PA) is a rare tumor of the skin that may arise from either the apocrine or the eccrine glands. Only 4 cases of PA in the auricle have been reported. We experienced the case of a 40-year-old woman who had a slowly growing, nontender auricle mass for 3 years. Under a clinical diagnosis of an epidermal inclusion cyst, we performed a total excision of the tumor with the skin and with direct closure. No recurrence was found during the 18 months of postoperative follow-up. Histologic examination confirmed a diagnosis of PA. Hematoxylin-eosin stain showed tubules that were lined with 2 layers of epithelial cells. The stroma was composed of the myxoid and chondroid matrices. Immunohistochemical staining was positive for cytokeratin, epithelial membrane antigen, and gross cystic disease fluid protein, whereas it was negative for S-100 and carcinoembryonic antigen. These findings suggested that this tumor originated from the apocrine glands. Only a few cases of PA in the auricle have been reported in the literature, 2 of which occurred in the helical rim. Recurrence is rare if there is complete resection of the tumor along with the surrounding capsule. We report herein a rare case of PA that developed in the auricle.