Keloidal Collagen May Be Produced Directly by αSMA-positive Cells: Morphological Analysis and Protein Shotgun Analysis.

Keloids are fibroproliferative lesions caused by abnormal dermal wound healing. Keloidal collagen (KC) is a pathognomic feature of keloids, but the mechanism by which it forms is unknown. This study aimed to evaluate the histopathology of KC and thereby gain clues into how it forms. Methods: The cross-sectional study cohort consisted of a convenience series of patients with keloids who underwent surgical excision. Skin pieces (3 mm2) were collected from the keloid center and nearby control skin. Histopathology was conducted with light and electron microscopy and immunohistochemistry. KC composition was analyzed with protein shotgun analysis. Results: Microscopic analyses revealed the ubiquitous close association between KC and αSMA-positive spindle-shaped cells that closely resembled myofibroblasts. Neither KC nor the spindle-shaped cells were observed in the control tissues. Compared with control skin, the collagen fibers in the KC were overall thinner, their diameter varied more, and their spacing was irregular. These features were particularly pronounced in the collagens in the vicinity of the spindle-shaped cells. Protein shotgun analysis did not reveal a specific collagen in KC but showed abnormally high abundance of collagens I, III, VI, XII, and XIV. Conclusions: These findings suggest that KC may be produced directly by myofibroblasts rather than simply being denatured collagen fibers. Because collagens VI and XII associate with myofibroblast differentiation, and collagen XIV associates with local mechanical stress, these collagens may reflect, and perhaps contribute to, the keloid-specific local conditions that lead to the formation of KC.

Hemodynamics and Vascular Histology of Keloid Tissues and Anatomy of Nearby Blood Vessels.

Keloids are red' invasive scars that are driven by chronic inflammation in the reticular dermis. The role of blood vessels in keloid behavior remains poorly understood. In the present study with 32 keloid patients, we examined the hemodynamics of keloid tissue, the anatomy of the blood vessels feeding and draining the keloids, and the vascular histology of keloids. Methods: Ten patients with large anterior chest keloids underwent near-infrared spectroscopy, which measured regional saturation of oxygen and total hemoglobin index in the keloid and surrounding skin. Another 10 patients with large chest keloids and three healthy volunteers underwent multidetector-low computed tomography. The extirpated chest keloids of 12 patients were subjected to histology with optical, CD31 immunohistochemical, and electron microscopy. Results: All keloids had a low regional saturation of oxygen and a high total hemoglobin index, which is indicative of blood congestion. Multidetector-low computed tomography revealed dilation of the arteries and veins that were respectively feeding and draining the keloid leading edge. Hematoxylin-eosin staining and CD31 immunohistochemisty revealed considerable neovascularization in the keloid leading edge but not in the center. Electron microscopy showed that the lumens of many vessels in the keloid center appeared to be occluded or narrowed. Conclusions: Keloids seem to be congested because of increased neovascularization and arterial inflow at the leading edge and blocked outflow due to vascular destruction in the center. The surrounding veins seem to expand in response to this congested state. Methods that improve the blood circulation in keloids may be effective therapies.

Toe Keloids Treated with Core Excision, Postoperative Radiotherapy, and Steroid Plaster.

Although keloids are common on the joints, precordial areas, and abdomen, toe keloids are rare. The limited literature to date also suggests that they can be difficult to treat. We experienced the case of a 21-year-old woman with toe keloids on the first, second, and third toes that arose after ingrown-nail operations at another hospital. The second toe keloid was resected but recurred. Since subsequent conservative treatments were ineffective, the patient was referred to our hospital. The first visit revealed three large keloids: in particular, the keloid on the second toe had engulfed the entire circumference of the toe. Surgery with the core-excision method and postoperative radiotherapy were performed. After the sutures were removed, the scars were treated for 24 hours/day with steroid plaster until the induration disappeared. One and a half years after the operation, recurrence was not observed and the appearance of the toes had improved greatly. Thus, combination therapy composed of core excision, radiotherapy, and steroid plaster therapy is highly effective for toe keloids.