Histochemical observations of enzymes in adenoameloblastoma. Histochemical comparisons of enzymes among tooth germ, adenoameloblastoma, and ameloblastoma

Adenomatoid odontogenic tumour with features of calcifying epithelial odontogenic tumour. (The so-called combined epithelial odontogenic tumour.) Clinico-pathological report of 12 cases

The combination of two odontogenic tumours is a rarely reported finding. To date only 10 cases of adenomatoid odontogenic tumour (AOT) combined with areas of calcifying epithelial odontogenic tumour (CEOT) have been published. This article describes the clinical, radiographical and microscopic findings of 12 cases of AOT, in which CEOT-like areas of variable sizes were found. These results suggest that such areas may be considered as a normal feature within the histomorphological spectrum of AOT.

Adenomatoid odontogenic tumor: biologic profile based on 499 cases

Topographically, the AOT occurs in peripheral and central variants, the latter further in follicular (with embedded tooth) and extrafollicular (no embedded tooth) types. The AOT is slow growing with few or no symptoms. Tumor growth may cause displacement of teeth rather than root resorption. The follicular AOT mimics a follicular cyst, the extrafollicular a residual or "globulo-maxillary" cyst and the peripheral a gingival fibroma. All variants of AOT show identical histologic features. The central variants account for 97.2%, 73.0% of which are follicular. The follicular variant (M:F ratio 1 to 1.9) is three times as frequent as the extrafollicular. The follicular variant is diagnosed earlier in life (mean age 17 yr) than the extrafollicular (mean age 24 yr). 53.1% of all variants occur within the teens (13-19 yr). Follicular AOT is associated with one embedded tooth in 93.2%. Maxillary permanent canines account for 41.7% and all four canines for 60.1% of AOT-associated embedded teeth. Ranking four among the odontogenic tumors the AOT is not a particularly rare tumor. Conservative surgical excision is the treatment of choice. Documented recurrences have not been reported.

Adenomatoid odontogenic tumour: co-expression of keratin and vimentin

Immunohistochemical observations of intermediate sized proteins in five cases of adenomatoid odontogenic tumour (AOT) are described. The immunohistochemical detections of keratins were made with polyclonal antiserum (TK, 41-65 kDa) and three monoclonal keratin antibodies (KL1: 55-57 kDa; PKK1: 40, 45, and 52.5 kDa and nos. 19, 18, 8; K8.12: nos. 16, 13) and vimentin and desmin monoclonal antibodies. Histologically, the tumour epithelia could be divided into two types: type A cells were a spindle or columnar shape and formed solid, ductal, tubular or whorled structures. Type B cells were small and compact cells at the periphery of the A cell-containing focus. Immunohistochemically, the type A cells showed very slight reaction with all antibodies to keratins, whereas the type B cells indicated slight-to-moderate expression of keratin and vimentin, and showed coexpression. Both types of cell showed a negative reaction for desmin. Only one case was associated with cystic lesions, and the cyst-lining was composed of thin squamous epithelium. Keratin expression in this epithelium was strong. In the histogenesis of AOT it was postulated that the tumour cells may have originated from undifferentiated odontogenic epithelium or stratum intermedium cells.

Clear cell odontogenic tumor: histochemical and ultrastructural features

Clear cell odontogenic tumor, a rare epithelial jaw lesion of putative odontogenic origin, histologically resembles clear cell adenocarcinomas. Ultrastructural and histochemical features are described and support a non-glandular derivation. The intraosseous neoplasm is characterized by ovoid nests of clear or finely stippled cells with a mature collagenous stroma. These cells are PAS-positive, diastase labile and fail to bind alcian blue. Enzyme histochemical reactions disclose dehydrogenase, non-specific esterase, and acid phosphatase positivity. Fine structural characteristics include plasma membrane microvilli, desmosomes, endoplasmic reticulum, free ribosomes, glycogen rosettes and lysosomes. Many cells exhibit a paucity of cytoplasmic organelles with prominent vacuolization. Centrioles and annulate lamellae are also encountered. Summarily, clinical, radiographic, histochemical and ultrastructural features indicate that this neoplasm is probably of epithelial odontogenic origin with cytodifferentiation emulating glycogen-rich presecretory ameloblasts.

Histoenzymological and ultrastructural study of a bifocal calcifying epithelial odontogenic tumor. Characteristics of epithelial cells and histogenesis of amyloid-like material

A calcifying epithelial odontogenic tumor, simultaneously located in the two jaws (maxilla and mandible) was examined by histochemical and electron microscopic methods. Squamous tumor cells without secretory polarity were different from those of common ameloblastoma. High activities of alkaline phosphatase and ATPases were demonstrated by light and electron microscopy on the cytoplasmic membrane, findings similar to those in the stratum intermedium cells of the normal dental germ from which these tumor cells seem to arise. The tumor cells, like preameloblasts of the dental germ, also produce a granulo-filamentous material in intracytoplasmic vesicles and discharge it into the stroma. This "pseudo-amyloid" substance represents an abnormal protein of the enamel matrix and calcification, mainly occurring in that substance, might be an attempt at mineralization.

An electron-microscopic and cytochemical study of follicular ameloblastoma

The ultrastructural and enzyme cytochemical features of two follicular ameloblastomas were investigated. The peripheral cells of the follicular areas in both lesions had several types of tall columnar cells which were highly polarized and showed varying degrees of cellular differentiation. These polarized cells had their nuclei situated away from the basal lamina, and often contained dilated strands of endoplasmic reticulum in the subnuclear cytoplasm. Some of these cells also contained dense-cored secretory granules, condensing granules and coated vesicles in the cytoplasm adjacent to the basal plasma membrane. These cells bore a striking resemblance to pre-ameloblasts and early secretory ameloblasts. Alkaline phosphatase and ATPase cytochemistry supported these morphologic observations. Interestingly, the central cells of the follicular areas were consistently negative for alkaline phosphatase activity as were the peripheral cells, while both cell types had ATPase activity demonstrable at their cell surface.

Ultrastructural localization of alkaline phosphatase in the calcifying epithelial odontogenic tumor

The localization of alkaline phosphatase in a calcifying epithelial odontogenic tumor obtained from a 53-year-old man was examined cytochemically. The majority of enzyme activity was associated with the epithelial cell membranes of the tumor, and faint activity was found in the cell membranes facing the adjacent stromal tissue. The reaction product of ALP was also detected in some membrane-bound vacuoles (lysosomes) and the Golgi apparatus of tumor cells. It is suggested that the appearance of enzyme activity associated mostly with the epithelial cell membrane may be related to transport function of cell membranes.

The odontogenic adenomatoid tumor. A comprehensive study of twenty new cases

Twenty new cases of odontogenic adenomatoid tumor are added to the literature, bringing the total number of reported cases to 152. The clinical, radiographic, and microscopic findings in these cases support the previously reported data for this lesion. The odontogenic adenomatoid tumor is a benign lesion which arises from residual odontogenic epithelium. It should be treated conservatively, as there is no indication that this lesion will recur. The histogenesis of this lesion, as well as the origin of the esinophilic droplet material, is discussed.