The difference is that individuals affected by GAP are much younger and the progression of disease appears more rapid. There is a poor serum response against infecting agentsDestruction is present that is not in balance with the amount of local irritants present
Generalized inter-proximal attachment loss on 3 or more permanent teeth, excluding the first molars or incisorsThe main distinction between the localized and generalized form of AgP lies in the number of teeth affected. GAP brings about attachment loss involving more than 30% of sites on teeth; effectively being at least three permanent teeth other than the first molars or incisors. Episodic nature of attachment loss Two main tissue responses have been found in GAP cases:Tissue may have severe acute inflammation and often presents with an angry red appearance and ulceration. There may be spontaneous bleeding or suppuration. This response is known to be present in the destructive phase, where there is presence of bone and attachment loss. The other response is known as a period of quiescence, where gingival tissue may appear with no inflammation, pink appearance with some possible stippling. In addition to this mild appearance there may be deep pockets upon probing. Radiographic features
The key diagnostic feature of AgP is vertical bone loss around teeth including the first molars and incisors. This tends to begin around puberty in otherwise healthy individuals. There may be an appearance of "arc-shaped loss of alveolar bone extending from the distal surface of the second premolar to the mesial surface of the second molar".
In all events, IMT is a rare tumor with a reported incidence in 2009 of 150–200 cases/year in the United States.IMT lesions typically consist of, and are defined by, myofibrolastic spindle cells, i.e. specialized cells that are longer than wide, have a microscopic appearance that merges the appearances of fibroblasts and smooth muscle cells (see myofibroblast), occur in normal as well as tumor tissues, and in normal tissues are commonly designated  fibroblasts. However, the lesions in some IMF cases are dominated by sheets of epithelioid cells (which may have rounded shapes) with only a minor component of spindle cells. Tumors with these characteristics  are regarded as a subtype of IMT termed epithelioid inflammatory myofibroblastic sarcoma (EIMS).The tumors in IMT and EIMS consistently contain pro-inflammatory white blood cells and in most cases tumor cells that express highly abnormal oncogenic (cancer-causing) fusion proteins such as those that contain the active portion of anaplastic lymphoma kinase (ALK). It is not clear whether this inflammation, the genetic abnormalities, or both contribute to the development of IMT but drugs blocking the activities of the fusion proteins made by these genetic abnormalities may be useful in treating the disease. Signs and symptoms
IMT was regarded as a tumor that occurs in children or young adults and presented in the lung, mesentery, greater omentum or, less commonly, heart, liver, spleen, pancreas, colon, small intestine, spermatic cord, prostate, uterus, eye orbit, peripheral or central nervous system nerves, brain meninges, spinal cord, or other sites.