Visual and pathologic analyses of keloid growth patterns.

Keloids grow and spread not only vertically but also horizontally, although hypertrophic scars do not grow beyond the boundaries of the original injury. Clinically, we have encountered keloids with regular and irregular (untypical) shapes. As the characteristics of the irregular growth patterns of keloids have not been studied yet, we analyzed the irregular growth of keloids both visually and pathologically.A total of 220 keloid specimens, each from a different patient, were surgically removed and used in this study. Through visual analysis, the preoperative shapes of these 220 keloids were classified into those with a regular shape (R group) and those with an irregular shape (IR group). Moreover, we distinguished between cases that had received keloidectomy previously and those that had not. We also determined whether the keloids were recurrent keloids or not. In both the R and IR groups, keloid specimens were studied histologically to examine for infection.In the R group, there were 156 cases (70.9%; 55 males and 101 females with a mean age of 33.68 years). Three patients (1.9%) had infection and 2 patients (1.3%) had undergone keloidectomy previously. In the IR group, there were 64 cases (29.1%; 24 males and 40 females with a mean age of 45.27 years). Thirty patients (46.9%) had infection and 24 patients (37.5%) had undergone keloidectomy previously. Statistically, the rates of infection and keloidectomy were significantly different between the R group and the IR group.Severe infection or operative history may be the cause of irregularly shaped keloids. Thus, in the absence of significant infection or a surgical history, the shape of keloids may be determined uniquely by skin tension.