Complex sentence: Sometimes it is blended with a marginal, plaque induced gingivitis, sometimes it does not involve the free marginal gingiva, but is found as a solitude red area within the attached gingiva (pictures).
Split into simpler sentences: Sometimes it is blended with a marginal, plaque induced gingivitis, or it does not involve the free marginal gingiva. It may also be found as a solitude red area within the attached gingiva (pictures).