The results suggest that the increased epithelial thickness observed in nifedipine- and cyclosporin A-induced gingival overgrowth is associated with increased mitotic activity, especially in the oral epithelium.

Our results show that the nature of drug-induced gingival overgrowth differs somewhat between immunosuppressive and nifedipine medications.

Immunosuppressive medication without concomitant nifedipine decreases the numbers of MC(TC) and MC(C) in overgrown gingiva. Chymase-positive mast cells may play a role in formation of gingival overgrowth, especially in patients receiving cyclosporin A (CsA) medication with no concomitant nifedipine. In this respect, nifedipine and CsA are different.

Inflammatory myofibroblastic tumor (IMT) is a rare lesion found mostly in children and young adults and originates from the lung, abdominopelvic region, and retroperitoneum. Clinical manifestations of IMT or imaging are nonspecific and diagnosis is based on histopathological and immunohistochemical findings. Minority of all IMTs will metastasize. IMT in the oral cavity is an extreme rarity and this is a first case report of IMT in maxilla causing delayed tooth eruption and multiple cervical root resorption with an 11-year-old child. The IMT reported here was positive for smooth muscle actin, vimentin, and anaplastic lymphoma kinase (ALK1) with immunohistochemistry. Only three IMTs of the jaws have been reported so far and none of them had delayed root eruption and tooth resorption. This unusual case of IMT in a child was also ALK1- positive supporting neoplastic origin of her tumor. The case presented here underscores the importance of histopathological examination of the tissue found in any root resorption especially in the case of multiple resorptions.

The reduced numbers of CD1a-labeled cells found in nifedipine-induced gingival overgrowth were similar to the reduced numbers of CD1a-labeled cells in gingival overgrowth associated with immunosuppressive medication.