[Carcinomas in papillary cystadenolymphomas of the parotid gland--definition and differential diagnosis (author's transl)]

Squamous cell carcinoma arising in a Warthin's tumor

Warthin's tumor is a well-defined salivary gland neoplasm consisting of epithelial and lymphoid components. However, malignant transformation is extremely rare. Such a patient who developed squamous cell carcinoma within a Warthin's tumor of the parotid gland is described and possible pathogenesis is discussed.

Extraparotid Warthin's tumor

Warthin's tumor (papillary cystadenoma lymphomatosum) is a well-known benign tumor of the parotid gland. Extraparotid tumors occasionally arise in the cervical region, where they may well be seen by the dermatologist. The following is a case report of an extraparotid Warthin's tumor encountered in a dermatology practice, with a review of the important clinical and histopathologic features of this tumor.

Malignant Warthin's tumour: a case study

Malignant transformation of a benign Warthin's tumour (adenolymphoma) is extremely rare. The light microscopic and ultrastructural features of an adenocarcinoma arising in a Warthin's tumour in the parotid gland are described. Light microscopy demonstrated a transition zone from the benign to the malignant component, and the malignant cells revealed oncocytic features by both light- and electronmicroscopy.

The World Health Organization's Histological Classification of Salivary Gland Tumors. A commentary on the second edition

The second edition of the World Health Organization's Histological Classification of Salivary Gland Tumors is more extensive and detailed than the previous edition published 20 years ago. The new edition is based on data regarding newly described tumor entities and the behavior and prognosis of the previously classified tumors. The distinct morphologic features of monomorphic adenomas justify their separation for purposes of identification. Among the carcinomas, various types were distinguished for purposes of recognition, prognosis, and treatment. The term tumor was replaced by carcinoma in the following two entities: acinic cell carcinoma and mucoepidermoid carcinoma. The tumor-like lesions were described in more detail.

Warthin's tumor

Warthin's tumor, classed as a monomorphic adenoma, ranks second to pleomorphic adenoma in the incidence of benign neoplasms of the parotid gland. By embryologic and clinicopathologic definitions, it is a neoplasm of the parotid gland and its environs, including parotid lymph nodes. Histopathologic diagnosis requires an oncocytic (mitochondria-rich) epithelium and lymphoid stroma. Malignant Warthin's tumors are rare and are carcinomas arising from the ductal component, or non-Hodgkin's lymphomas arising from the lymphoid tissue.

Oncocytic adenocarcinoma arising in Warthin's tumor

Warthin's tumor (adenolymphoma) is a monomorphous adenoma of the salivary glands well characterized histologically. Its clinical evolution is almost invariably benign, the malignant change being extremely unusual. We present the case of a 67 year-old man with a right retromandibular tumor which has evolved over a two year period, with peripheral involvement of V, VI and VII cranial nerves on the same side, and direct invasion of intracranial structures. The biopsy revealed a classic adenolymphoma which shows foci of well differentiated adenocarcinoma. Transitional areas between benign and malignant epithelium were evident. In addition, histological findings support the hypothesis of the origin of adenolymphoma from epithelial ducts trapped in the regional lymphatic tissue.

Carcinoma ex papillary cystadenoma lymphomatosum. Malignant Warthin's tumor

Epithelial malignancy in a Warthin's tumor exists in three forms. The most common is a coexistent, separate neoplasm. Metastasis to the lymphoid component of Warthin's tumor follows, and the least common is a primary carcinoma arising from the ductal component of the tumor.

Squamous cell carcinoma arising in Warthin's tumor of the parotid gland. A light, electron microscopic, and immunohistochemical study

The fourth recorded squamous cell carcinoma arising in a pre-existing Warthin's tumor is reported. A gradual transition was noted from the mitochondria-rich epithelium of benign portions of the tumor to organelle-poor cells forming the areas of squamous metaplasia and carcinoma. Bundles of intermediate filaments corresponding to immunoreactive keratin were demonstrated in all epithelial parts of the tumor and also in the epithelium of a benign Warthin's tumor that was studied in parallel.

Malignant papillary cystadenoma lymphomatosum. Light and electron microscopic study

A case of malignant papillary cystadenoma lymphomatosum was investigated by light and electron microscopy. Histologically, the tumor consisted mainly of a characteristic papillary cystadenoma lymphomatosum, but the feature of epithelial components varied greatly in separate portions of the tissue; papillary adenoma-, tubular adenocarcinoma-, acinic cell tumor- or oncocytoma-like features were observed, the tumor cells showing "atypia" in major components. Numerous intracytoplasmic inclusions were found in many oncocytic cells arranged in acinar structure, and stained with PAS, AZAN or Alcian blue. Electron microscopically, large numbers of very large, swollen and closely packed mitochondria were observed in almost all the tumor cells. The intraplasmic inclusions were composed mainly of a long dense body enclosed by a single unit membrane, and the contents constituted bundles of fine filament running parallel to the longer axis. The inclusions were often observed to unite with lysosomes and to co-exist with secretory granules in the cytoplasm.

The expression of different intermediate-sized filaments in human salivary glands and their tumours

The intermediate-sized filaments can be divided into several groups which are characteristic of different types of tissues (e.g.: epithelial, mesenchymal, muscle, astrocytic and neural origin). Antibodies specific for some of these filament types have been used to analyse a group of salivary gland tumours. Prekeratin-positive cells were seen in the normal gland, cystadenolymphomas, mucoepidermoid tumours, and squamous cell carcinomas which are all tumours of epithelial origin. The pleomorphic adenomas showed the presence of some cells which appeared to contain both prekeratin and vimentin. The results are discussed with respect to their histogenetic implications.

Monomorphic adenomas of major salivary glands: a histologic study of 96 tumours

It has been a little over a decade since monomorphic adenomas were formally recognized as a class of salivary gland tumours separable from the more common pleomorphic adenomas. This short time and a relatively low incidence, estimate at less that 2% of all salivary gland tumours, have not allowed histopathologic review of any sizable number of the tumours. The present study of 102 monomorphic adenomas; 96 in major salivary glands, establishes the histologic heterogeneity of the tumours and permits a classification based on this histologic variation as well as differences in histogenesis. For a number of the tumours, a hamartomatous deviation from stages in the normal organogenesis of salivary glands is strongly suggested. An analogous relationship exists for adenexae of the skin and their tumours. Identification of 12 tumours bearing a striking resemblance to dermal eccrine cylindromas carries the analogy further. Given the acceptance of the classification and time, a correlation of the subtypes of monomorphic adenoma with biological behaviour should follow.

Histologic subclassification of the cystadenolymphoma of the parotid gland. Analysis of 275 cases

Cystadenolymphomas (CAL) of the parotid gland are variable in their epithelial differentiation and the ratio of the epithelial tumor component to lymphoid stroma. Two hundred and seventy five cases of CAL from the files of the Salivary Glands Register of the Institute of Pathology, University of Hamburg (1965-1979) were analysed. Their pathogenesis from parenchyma included in regional lymph nodes is discussed. The following subclassification was established. 1. Depending on to the ratio of epithelial tumor component to lymphoid stroma, three subtypes were distinguished. Subtype 1, "typical CAL" with an epithelial tumor component of 50%, amounted to 77% of all cases of CAL studied. Oncocytic differentiation and focal metaplasia to goblet cells or squamous epithelium was also found. 13.5% of CAL were classified as subtype 2, "stroma-poor CAL" with an epithelial tumor component of 70 to 80%. The tumor structure was similar to that of an oncocytoma in places. Two per cent of the CAL were in subtype 3, "stroma-rich CAL" with an epithelial tumor component of only 20 to 30%. Subtype 3 was found solely in men. The average age at presentation (61 years) was slightly lower than that of all the cases studied (65 years). 2. In 7.5% of the cases large areas of squamous cell metaplasia and regressive changes was found within a CAL. These cases were classified as subtype 4 ("metaplastic CAL"). The average age was 67 years. The case histories showed that 20% of these metaplastic CAL had previously been irradiated. 3. Bilateral CAL was found in 7.5% of the cases. In 4% multifocal CAL occurred in the parotid gland unilaterally. Recurrences were observed in 2% of all CAL. 4. Carcinoma in CAL is rare (we found two cases in our own material). In 50% of all cases reported radiotherapy was mentioned in the case histories. 5. Malignant tumors coincident with CAL were recorded in 3% of the cases. 6. The lymphoid stroma showed reaction patterns similar to those of the regional lymph nodes. These included granulomatous changes (foreign body granuloma with cholesterol deposits, tuberculosis) and tumor metastases. In the neighborhood of oncocytic tumor epithelium focal accumulations plasma cells forming IgA and IgG were found. Metaplasia to squamous epithelium is believed to be caused by circulatory disturbances, irradiation, and other noxae. In the differential diagnosis of the stroma-poor subtype 2, oncocytoma and cystic sialadenoma must be excluded, and in the differential diagnosis of subtype 4 (the metaplastic CAL), sebaceous adenoma, mucepidermoid tumor, squamous cell carcinoma, lymphoepithelioma, and other non-tumorous lesions of the parotid gland (lymphoepithelial cysts, myoepithelial parotitis) must be ruled out. Our findings suggest that CAL develops from parenchyma included in parotid lymph nodes with the oncocytic ductal epithelium representing the neoplastic component.