Osteolipoma in the glabella: pathogenesis associated with mesenchymal lipoma-derived stem cells.

Lipoma is a benign tumor that often arises in the craniomaxillofacial region. Osteolipoma containing bone tissue is very rare and the developmental mechanism is unclear. Mesenchymal stem cells in adipose tissue that have potential to differentiate into fat, bone, cartilage, and vascular components may be involved in the development of osteolipoma, in which adipose and bone tissues coexist. We encountered a patient with osteolipoma that arose in the glabella. We describe the case and the results of an investigation of the presence in lipomas of mesenchymal stem cells with differentiation potential similar to that of normal adipose cells. The patient was a 66-year-old woman. Histopathologically, bone tissue surrounded by fibrous connective tissue was present in the nodular adipose tissue and was diagnosed as osteolipoma. Mesenchymal stem cells were collected by collagenase treatment of lipoma tissue, and their potential to differentiate into fat, bone, and cartilage was shown. On the basis of this study, we suggest that lipoma-derived mesenchymal stem cells are the basis of the pathogenesis of osteolipoma. The conditions that induce differentiation of mesenchymal stem cells into bone remain to be investigated.

New technique of decompressive skinplasty with artificial dermis for severe brain swelling: technical note.

In cases of severe uncontrollable brain swelling, simple skin closure often increases intracranial pressure. This study examined the efficacy of a new technique of decompressive skinplasty to decrease intracranial pressure following decompressive craniectomy in cases of severe traumatic brain injury with uncontrollable brain swelling. In our technique, we use artificial dermis to avoid elevation of intracranial pressure. After performing decompressive craniectomy and duraplasty with artificial dura, decompressive skinplasty with artificial dermis was performed in 5 patients for whom simple skin closure caused the intracranial pressure to elevate under intracranial pressure monitoring. Artificial dermis was grafted onto the region to cover the skin defect and sutured to the skin with 4-0 nylon sutures. Two weeks after surgery, the silicone layer of the artificial dermis was removed and ointment treatment was continued until complete epithelialization was achieved. In all cases, decompressive skinplasty contributed dramatically to decreasing the intracranial pressure in patients with uncontrollable brain swelling. The technique of decompressive skinplasty with artificial dermis contributed to dramatically decreasing the intracranial pressure. More cases are required to investigate the indications for this technique.