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

The role of tight junctions in cancer metastasis

Over the last decade, it has become apparent that the tight junction (TJ) is a key component in tumour progression and metastasis. In addition to its role in the control of paracellular diffusion of ions and certain molecules, the TJ has a vital role in maintaining cell to cell adhesion and tissue integrity. Changes in the expression and/or distribution of TJ proteins can result in loss in cohesion of the TJ structure, which in turn results in the ability of cancer cells to become invasive and then ultimately lead to the metastasis of cancer cells. This review will discuss recent insights into how TJ are involved in the process of tumour metastasis.

Acinic cell carcinoma of the trachea

Acinic cell carcinoma (ACC) appears primarily in the parotid gland. It is extremely rare in the respiratory tract and only a few cases of ACC in the lungs, larynx, nose, and paranasal sinuses have been described. We present here a case of ACC located in the trachea and discuss possible therapeutic strategies in the light of this tumor behavior relating to other sites.

Nucleolar organizer regions in malignant salivary gland tumors

Proliferative activity of carcinomas arising from salivary glands was analyzed by enumeration of argyrophilic nucleolar organizer regions (AgNORs). The mean numbers of AgNORs in the various tumors were as follows: mucoepidermoid carcinoma, 2.20; acinic cell carcinoma, 2.51; adenoid cystic carcinoma (ACC), 2.57; carcinoma in pleomorphic adenoma, 1.00 (benign component) and 3.99 (cancer-bearing area); salivary duct carcinoma, 4.49; polymorphous low-grade adenocarcinoma, 3.37; sebaceous carcinoma, 2.57; oncocytic carcinoma, 4.63; adenocarcinoma, 4.53. Cells of most tumors showed heterogeneous activity within the same tumor. In mucoepidermoid carcinoma, the mucous cells had suppressed activity in comparison with the epidermoid cells and intermediate cells. In ACC, the activity of the tumor cells increased according to growth pattern in the order tubular, glandular and solid. In carcinoma in pleomorphic adenoma, vigorous proliferative activity was observed in the malignant component, whereas less active cells were seen in the myxoid or chondroid matrix. AgNOR staining was useful for distinguishing benign from malignant regions in carcinoma in pleomorphic adenoma. Our results suggest that mucoepidermoid carcinoma, acinic cell carcinoma and ACC, except for that with a solid growth pattern, may be considered as low-grade malignancies, whereas solid-type ACC, the cancer component in carcinoma in pleomorphic adenoma and some of the other carcinomas have high-grade malignant behavior.

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.

Morphological changes of intercellular junctions in the rat submandibular gland treated by long-term repeated administration of isoproterenol

Long-term repeated administration of isoproterenol (IPR) 2 mg/100 g bw, once daily for ten days, resulted in morphological changes in the intercellular junctions of rat submandibular glands, which were investigated by means of the freeze-fracture technique. A significantly increased number of tight-junctional strands was present. These junctional strands extended much deeper toward the basal membrane than those in normal acinar cells. The basal frontier strands that branched from the networks of tight junctions were elongated and had either free-endings or terminal loops, which were more frequently observed in the IPR-treated acinar cells than in untreated acinar cells. Some of the strands of tight junctions were connected to small gap junctions. The diameters of gap junctions were not significantly different from those of control acinar cells. However, smooth areas devoid of particles were found intermingling with the usual packed particles in irregularly shaped small gap junctions. There was no significant difference between the desmosomes of IPR-treated and untreated acinar cells, in terms of either morphology or distribution. These changes in junctional morphology in the IPR-treated acinar cells resemble those seen in salivary glands during development, and in some experimental conditions including tumorous changes.

Acinic cell carcinoma of minor salivary gland origin

We describe a case of acinic cell carcinoma of the right soft palate in a 65-year-old man. The primary symptom was a painless swelling of the palate, which was partially ulcerated with a granulomatous appearance. Ultrastructurally, the tumor cells were mainly composed of differentiated acinuslike cells containing numerous round secretory granules identical to those in normal serous salivary glands. The tumor cells frequently contained numerous long crystalloid structures in the cytoplasm. Furthermore, tumor cells demonstrating degrees of squamous differentiation were present. These cells contained intracytoplasmic keratin filaments and a few keratohyaline granules. They formed a glandular acinar space in direct contact with the typical acinic cells with secretory granules. These observations suggest that acinic tumor cells have a degree of multipotentiality.

Acinic cell carcinoma of the nasal cavity: electron-optic and immunohistochemical observations

The fourth example of an acinic cell carcinoma arising in the sinonasal tract is presented. Because of its unusual and atypical histologic appearance, correct diagnosis required electron microscopic analysis and the demonstration of intracellular amylase by immunohistochemical stains.