Acinic cell tumors of minor salivary glands

Most nonparotid "acinic cell carcinomas" represent mammary analog secretory carcinomas

Acinic cell carcinoma (ACC) is a low-grade salivary gland malignancy characterized by serous acinar differentiation. Most ACCs arise in the parotid gland, but ACCs have been reported to originate in nonparotid salivary glands where serous acini are less abundant. Given the recent discovery of mammary analog secretory carcinoma (MASC)-a salivary malignancy that histologically mimics ACC-a retrospective reevaluation of nonparotid ACCs is warranted. The surgical pathology archives of The Johns Hopkins Hospital were searched for all ACCs arising outside of the parotid gland. For each case, the histologic slides were reviewed; immunohistochemical analysis (mammaglobin, S100 protein) was performed; and confirmatory ETV6 breakapart fluorescence in situ hybridization assay was completed. Demographic and clinical data were obtained from the medical records. Fourteen extraparotid tumors diagnosed as ACC were identified. Eleven of 14 (79%) tumors harbored the ETV6 translocation (oral cavity=9 of 11; submandibular gland=2 of 2). The translocation-positive tumors occurred in 7 women and 4 men ranging in age from 20 to 86 years (mean, 56 y) and usually presented as painless masses. Immunohistochemistry for mammaglobin and S100 was positive in all 11 translocation-positive tumors but negative in the 3 translocation-negative tumors. Histologically, the translocation-positive tumors exhibited uniform cells with vacuolated cytoplasm, microcystic/cystic and papillary architecture, and intraluminal secretions; however, the presence of basophilic cytoplasmic granules was conspicuously absent. Basophilic cytoplasmic granules, indicative of true serous acinar differentiation, were present in the 3 translocation-negative tumors. Of the translocation-positive tumors, only 1 locally recurred, and none metastasized. Most alleged ACCs of nonparotid origin actually represent misclassified MASCs. The impact of diagnostic error is mitigated by the low-grade nature of MASC that, like ACCs, do not appear to be clinically aggressive.

Unmasking MASC: bringing to light the unique morphologic, immunohistochemical and genetic features of the newly recognized mammary analogue secretory carcinoma of salivary glands

Mammary analogue secretory carcinoma (MASC) is a recently described salivary gland neoplasm that is characterized by its striking morphologic and molecular similarities to secretory carcinoma of the breast. This review highlights the characteristic clinical, histologic, immunophenotypic, and molecular features of MASC, and draws attention to the differential diagnosis of this increasingly recognized tumor.

Central odontogenic fibroma current concepts

The author reviews current knowledge concerning the central odontogenic fibroma, which at present in incompletely understood, and reaches the following conclusions. 1) The separation of this lesion into simple and WHO types remains valid because they exhibit different histologic features. However, more care should be taken in rendering the diagnosis of the WHO type than in the past; unlike the simple type, it is a fibroblastic lesion. 2) Complex central odontogenic fibroma is a more appropriate term than the WHO type because the WHO does not use the latter term in its 1992 manual. 3) The microscopic distinction of simple odontogenic fibroma from desmoplastic fibroma remains difficult in some cases. 4) The granular cell odontogenic tumor, which has sometimes been referred to as a type of odontogenic fibroma, is a separate entity, although some simple odontogenic fibromas exhibit scattered granular cells. 5) The separation of lesions that have been reported recently as odontogenic fibromas with giant cell reactions from central giant cell granulomas that exhibit foci of odontogenic epithelium requires further study.

The central odontogenic fibroma and the hyperplastic dental follicle: study with Picrosirius red and polarizing microscopy

The central odontogenic fibroma (COF) is an uncommon odontogenic tumor in which the microscopic appearance is similar to that of the hyperplastic dental follicle (HDF). Distinction between these lesions is based mainly on their clinical and radiologic features. The collagen of 5 cases of COF and 13 cases of HDF was studied histochemically by staining sections with Picrosirius red and examining them by polarizing microscopy. Polarization colors of the collagen fibers of the lesions were recorded according to their width. While no differences were seen between the polarization colors of thin fibers (<0.8 mm) in both lesions, the polarization colors of thick fibers (1.6-2 mm) of COF were significantly more green and greenish-yellow as compared with those of HDF. These findings suggest that the Picrosirius red polarization method can be used as a diagnostic tool to differentiate between COF and HDF..

Adenomatoid odontogenic tumorlike lesion in a male Wistar rat

An odontogenic tumor in the maxilla of a male Wistar rat is described. The tumor consisted of large epithelial areas with peripheral palissading and with juxtaepithelial material resembling dentin. The neoplastic odontogenic epithelium seems capable of inducing peridental mesenchyme to form a kind of dental hard tissue normally not present at that site.

Acinic cell carcinoma of minor salivary gland origin

The occurrence of acinic cell carcinoma in the minor salivary glands appears to be exceptional. A review of the English language literature revealed about 80 previously reported cases. In this paper, the clinical behaviour and pathological findings in three cases are reported. The tumours took their origin from the hard palate, soft palate and lower lip. The three cases presented with malignant clinical behaviour; all three recurred. In one case the local recurrence was multinodular with capsular infiltration. Two cases developed regional lymph node metastasis, and one metastasized to the lung and liver. In one the tumour infiltrated bony structures, and nerve in another. These cases tend to support the belief of some authors that acinic cell 'tumours' are clinically malignant and should be included in the carcinoma group.

Central acinic cell carcinoma of the mandible: report of a case

A case is reported of a central acinic cell carcinoma of the mandible. This is an unusual site for this rare tumour and to our knowledge only three cases have been previously reported in the literature.

A rare variant of acinic cell carcinoma of the upper lip: a case report and review of the literature

Acinic cell carcinomas of the lip are most uncommon. An exhaustive search of the Japanese- and English-language literature has revealed only 17 previously reported cases. One additional occurrence, a rare variant of this type of neoplasm, with mucous differentiation, that occurred in the upper lip of a 60-year-old man is described here. A brief review of the literature on this type of lip tumor is also given.

Acinic cell carcinoma of salivary glands: 16 cases with clinicopathologic correlation

Sixteen cases of acinic cell carcinoma (ACC) of salivary glands were studied and their different clinicopathologic aspects were analysed. ACC occurred more frequently in the 5th and 6th decades of life, and was seen exclusively in major salivary glands. The main complaint of the patients was the presence of a mass, and the majority of the tumors were Stage III and IV when first seen in our institution. The tumors were divided into three histologic grades based on cellular pleomorphism, mitotic activity, and necrosis. This study showed correlation between prognosis and grading. Other important factors in the prognosis were the type of treatment and the duration of symptoms. Surgical resection with free margins is the treatment of choice.

Ultrastructural morphology and cellular differentiation in acinic cell carcinoma

Acinic cell carcinomas, in some instances, contain a component of intercalated duct cells. However, the manner in which this element is integrated within the more obvious acinar cells, as well as the role neoplastic intercalated duct cells play in determining morphologic patterns in acinic cell tumors, has not been fully investigated. Ultrastructural study and immunostaining with antibodies to cytokeratins and to S-100 protein carried out in nine cases of parotid acinic cell carcinoma suggest two basic differentiation patterns. In three cases, the lesions were essentially composed of acinar cells (with variation in the number and form of secretory granules), and one of these tumors was unique in having ultrastructural evidence of differentiated myoepithelial cells. In the second group of six cases, there was light microscopic, ultrastructural, and immunohistochemical evidence of a significant component of intercalated duct cells. By means of both immunostaining (intercalated ducts were positive for keratin and S-100 protein; acinar cells were negative for both antigens) and electron microscopy, flattened-to-cuboidal intercalated duct cells were noted to enclose and, presumably, to be involved in the formation of microcystic spaces. Acinic cell carcinomas with a more solid growth pattern contained groups of intercalated duct cells positive for keratin and S-100 protein. Ultrastructurally, these cells were organized into well-formed ducts related to nests of acinar cells. Acinic cell carcinoma is another class of salivary gland tumor in which there can be an integrated proliferation of intercalated duct and acinar cells and, infrequently, of myoepithelial cells, all organized in a simulation of the intercalated duct-acinar unit of the normal salivary gland.

Multiple acinic cell carcinoma. Some histological and ultrastructural features of a case

A case is presented of multiple acinic cell carcinoma, occurring synchronously in the left parotid gland and in the right submaxillary gland of a 75-year-old male patient. Fourteen cases of primary multiple acinic cell carcinoma have previously been reported, all bilateral parotid gland tumours. To our knowledge this is the first report of extraparotid localization of an acinic cell carcinoma in a patient presenting multiple salivary gland tumours. The histologic and ultrastructural characteristics of the tumours are described and a review of the literature is given.

Acinic cell carcinoma of the cheek

An additional case report of the rare minor salivary gland tumor, acinic cell adenocarcinoma, has been reported. This is the twenty-first case in which the cheek has been the primary site. The tumor was treated by wide local excision and the patient is currently being followed by a large medical center's tumor board.

Localization of free secretory component in pleomorphic adenomas of minor salivary gland origin

Secretory component (a glycoprotein) is an antigenically distinct portion of the secretory immunoglobulin A, which has been identified in a number of normal and neoplastic epithelial cells. Localization of secretory component was determined in pleomorphic adenomas of minor salivary gland origin using the four-step peroxidase-antiperoxidase technique. Antiserum that detected only free secretory component (FSC) was used. Staining for secretory component was noted in the epithelium that lined duct-like spaces; but was absent in myoepithelial cells and mucous acini. These findings suggest a role for FSC in evaluating the histogenesis of various salivary gland neoplasms.

Acinic cell carcinoma arising in the glossopalatine glands: a report of two cases with electron microscopic observations

Two cases of acinic cell carcinoma arising in the glossopalatine glands were examined with the electron microscope by means of conventional thin sectioning and freeze-fracturing. Light and electron microscopic observation revealed that the tumors consisted of three types of cells: serous-type, ductlike, and vacuolated cells. Serous-type cells had numerous secretory granules, some of which were discharged into the intercellular spaces. Ductlike cells were smaller, usually lacked secretory granules, and were similar to intercalated duct cells. Vacuolated cells had electron-opaque vacuoles in the cytoplasm. Our findings supported the hypothesis that acinic cell carcinoma may represent a neoplasm of multipotential duct cells which have differentiated mainly into granulated serous cells. Freeze-fracture images of this tumor revealed that tight junctions were composed of ten or more interlinked strands with elongation of basal frontier strands. These findings suggested that the junctional morphology of the tumor resembled that of developing salivary glands and was associated with the degree of cellular differentiation.

Acinic cell adenocarcinoma. A clinicopathologic analysis of 294 cases

Two hundred and ninety-four cases of acinic cell adenocarcinoma were reviewed for the purpose of defining the clinical parameters and determining the distribution of the four histomorphologic tissue patterns and five cell types for correlation to biologic behavior. The vast majority occurred in the parotid gland. There was a male predominance and a peak incidence in the third decade of life. The tumors were usually less than 3 cm in diameter and were slow growing. Pain was a common symptom, but was not indicative of prognosis. Nearly one half of the neoplasms exhibited multiple tissue growth patterns, and three fourths of the tumors displayed more than one cell type. The microcystic pattern was seen most frequently, regardless of the biological behavior of the tumors. The well-differentiated acinic cell was the most prevalent cell type except in cases with metastases, where the intercalated-duct cell type was slightly more frequent. Follow-up of 244 cases revealed a recurrence rate of 12%, a metastatic rate of 7.8%, and death rate of 6.1%. Since all histomorphologic patterns and cell types were manifest in tumors which recurred, metastasized, or caused the death of the patients, it seems appropriate to consider these neoplasms as low-grade adenocarcinomas rather than essentially benign with occasional unpredictable malignant behavior.

Histopathology of benign gingival fibroblastic lesions with special reference to odontogenic fibroma and recurrence rates

Histopathologic and clinical reexamination of 84 cases diagnosed as peripheral odontogenic fibroma showed 56 cases with no evidence of recurrence, 12 with possible single recurrence and 16 with verified single or multiple recurrences. An effort was made to correlate the histopathologic appearance with the recurrence rate. Three different types of lesions could be identified: fibrous epulis, calcifying fibroblastic granuloma and various types of "fibroma", also showing a high recurrence rate. Our findings show that neither histomorphology nor recurrence rate can be used as a definite criterium to separate neoplasia such as odontogenic fibroma from other gingival fibrous overgrowths.

Acinic cell tumor of the minor salivary glands

The histologic characteristics and clinical features of six new cases of ACT of the minor salivary glands are reported. These neoplasms accounted for 3.8% of all the minor salivary gland tumors examined by our service. Three cell types were identified: acinar, vacuolated, and intercalated duct-cell. Those cell types were organized in three growth patterns: solid, papillary, and microcystic. Tumor cells were PAS positive both before and after treatment with diastase. Occasionally, they were slightly positive to mucicarmine staining. According to our study, ACT occurs in adult life, apparently without sex preference. Asymptomatic swelling was the most frequent presenting symptom; however, on occasion pain and ill-fitting dentures were reported. Most of the tumors in were described as fixed soft tissue masses, less than 1.5 cm in diameter. No recurrences or metastases were seen in any of the patients for a mean period of four years. Simple surgical removal was the therapeutic measure used in all cases.