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Query: UMLS:C0001430 (adenoma)
 21,222 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The case is described of a 23-year-old female patient presenting with unilateral proptosis, headaches, and transient epiphora. Surgery revealed an encapsulated tumour composed exclusively of spindle-shaped cells within a richly vascularised myxoid stroma. Immunohistochemical staining showed focal positivity for smooth muscle actin, vimentin, and glial fibrillary acidic protein. These combined findings are interpreted as providing evidence of a myoepithelioma, which may be regarded as a monomorphic adenoma consisting solely of myoepithelial cells. To our knowledge this is only the second report of such a tumour in the lacrimal gland.
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PMID:Myoepithelioma of the lacrimal gland: report of a case with spindle cell morphology. 132 39

Myoepithelioma is a rare neoplasm of the salivary glands which is now recognized as an individual entity in the revised WHO classification. In this study, eleven benign tumours are presented. Most patients gave a history of a slowly enlarging mass, which was cured by surgical excision. However, one case recurred several times over 50 years, and another still has residual tumour and removal is not possible. The histological appearances included solid, myxoid and reticular growth patterns, composed predominantly of spindle shaped or plasmacytoid (hyaline) cells. Many of the tumours also contained occasional small ducts. All 11 tumours were positive for S-100 protein, variable reactions being seen for various other antigens--keratins, human milk fat globulin, carcinoembryonic antigen, alpha smooth muscle actin and vimentin. It is probable that myoepithelioma constitutes one end of a biological spectrum which also includes pleomorphic adenoma and some (non-membranous) basal cell adenomas. In practice, however, we still advocate retention of myoepithelioma as a separate diagnostic category, on the grounds that it has a range of distinctive microscopic appearances and poses its own unique problems in correct identification.
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PMID:Benign myoepithelioma of the salivary glands: a true entity? 755

Basal cell adenocarcinoma is a recently defined category of salivary gland neoplasms. As the terminology implies, this group of tumors has many histopathologic features that are similar to the more well-known basal cell adenomas. To better characterize these tumors, 23 basal cell adenocarcinomas were reviewed and compared with 11 basal cell adenomas with the use of light microscopic and immunohistochemical methods. Evaluation of cytokeratin, S-100 protein, glial fibrillary acidic protein, carcinoembryonic antigen, epithelial membrane antigen, smooth muscle actin, vimentin, B72.3, Ber-EP4, and milk fat globulin immunoreactivity was performed. Parallel to the morphologic similarity, the immunoprofiles of the basal cell adenocarcinoma and basal cell adenoma were quite similar. Both tumors showed reactivity patterns indicative of ductal epithelial and myoepithelial differentiation. In addition, reactivity to some polymorphic epithelial mucins was observed, which suggested glandular differentiation. The identification of antigens found normally in myoepithelial and epithelial cells supports the concept that these tumors are derived from pluripotential salivary gland epithelial cells. The comparable immunohistochemical profiles imply evolvement from similar cell lines and lead us to conclude that distinction between the two is not possible on the basis of these findings.
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PMID:Immunohistochemical analysis of basal cell adenocarcinoma. 767 20

Malignant myoepithelioma of the salivary gland is discussed in terms of its clinical behaviour, morphological features and the frequent pre-existence of a pleomorphic adenoma. The study comprised six female and four male patients aged 14-63 years (mean age 38.9 years). Two tumours presented as intraoral lesions and eight were located in the parotid gland. Tumour cells displayed a morphological spectrum ranging from round epithelioid cells to spindle-shaped and stellate cells. Most cells displayed reactivity for high molecular weight keratins and in four tumours there was strong immunoreactivity for smooth muscle actin. Malignant myoepithelioma seems to arise in two different clinical settings: either de novo or in a recurrent pleomorphic adenoma. De novo malignant myoepitheliomas arise in normal salivary gland, tend to be more aggressive and have a short clinical history. Recurrences may not develop or may occur as a single event within a short time interval, and metastases develop in the lungs. Malignant myoepitheliomas arising in recurrent pleomorphic adenomas have a long clinical history, are characterized by multiple recurrences and have to be distinguished from aggressive carcinomas arising in these adenomas. In contrast, the tumours described in the present series arising in pleomorphic adenomas showed local aggressiveness and metastases did not occur until decades after the first treatment. The general opinion that all malignant tumours that arise from pleomorphic adenomas are highly aggressive is not confirmed by the present study.
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PMID:Malignant myoepithelioma of salivary glands: clinicopathological features of ten cases. 811 28

The histologic and immunohistochemical features of three congenital pedunculated nasopharyngeal midline masses are reported. The follow-up in all cases was uneventful. The tumors were characterized by solid and cystic squamous nests and ductlike structures focally continuous with the surface squamous mucosa of the tumor. Most of epithelial structures coalesced with densely cellular stroma-like nodules. Immunoperoxidase staining showed the presence of epithelial markers in both spindle cells and epithelial structures. Spindle cells were also reactive to vimentin and smooth muscle actin, revealing their myoepithelial phenotype. Based on these observations, a diagnosis of salivary gland anlage tumor, also called congenital pleomorphic adenoma of the nasopharynx, was made. The similarity of these tumors' architecture and cellular composition to the normally developing salivary gland has led to the hypothesis of a tumorlike, hamartomatous lesion developing in a site in which minor salivary gland tissue occurs. This report reviews 12 identified cases of this tumor, of which all but one (in which the patient died of sepsis) had a favorable outcome. In an infant with respiratory distress and/or feeding difficulties, these tumors must be differentiated from other midline masses such as encephaloceles and teratomas. They appear curable by surgical exeresis only.
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PMID:Salivary gland anlage tumor of the nasopharynx: a clinicopathologic and immunohistochemical study of three cases. 902 95

The phenotype of the proliferated spindled cells and the histogenesis of inflammatory fibroid polyp (IFP) have been a matter of debate. To clarify the immunohistochemical profile of the main cellular component, we reviewed histologically and studied immunohistochemically 11 cases (12 lesions) of IFP of the stomach. The lesions ranged in size from 0.4 to 3.0 cm (mean, 1.0 cm). All of the IFPs occurred in the antrum. Seven cases (63.6%) were accompanied by carcinoma or adenoma, which in two cases was present in covering epithelium. Grossly, eight IFPs were sessile, and four were polypoid. Microscopically, seven (58.3%) occupied both the mucosa and submucosa. Four (33.3%) were confined to the mucosa, and one was localized only in the submucosa. They were characterized by proliferation of relatively uniform spindled cells, often in a whorl-like arrangement around the blood vessels and glands. Eosinophilic and lymphocytic infiltration of varying degree was always present. The spindled cells in all of the IFPs were diffusely immunoreactive for vimentin and CD34. Seven (58.3%) were focally positive for histiocytic markers, such as KP1 and HAM56. Three (25%) showed focal immunoreactivity for alpha smooth muscle actin. Cytokeratin, desmin, S100 protein, Factor VIII RAG, and Ki-67 were negative in these spindled cells. The principle proliferating cells in IFPs in this study showed variable degrees of histiocytic and myofibroblastic lines of differentiation. Under the influence of some etiologic factors, the primitive, uncommitted spindled mesenchymal cells exhibiting CD34 immunoreactivity around the blood vessels and glands in the lower portion of mucosa and submucosa might play a role in development of IFP.
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PMID:CD34 expression by inflammatory fibroid polyps of the stomach. 916 Mar 9

A myoepithelial carcinoma, a rare malignant salivary gland neoplasm, arose in a pleomorphic adenoma of the parotid gland. The initial tumour was a pleomorphic adenoma with epithelial and myoepithelial elements. Subsequently the tumour recurred twice and was characterised by invasion of the mandible. Histological examination of the second recurrence showed a malignant spindle cell neoplasm with an infiltrative growth pattern and a high mitotic rate. There was involvement of local lymph nodes. The immunophenotype was characteristic of myoepithelial differentiation: tumour cells stained positively with anticytokeratin antibodies, S-100 protein, alpha smooth muscle actin, and vimentin. Electron microscopy confirmed myoepithelial differentiation, with small foci of keratinocytic phenotype. Large numbers of tumour cell nuclei were reactive with the anti-p53 antibody, DO-7, in contrast to the two previous resections. Thus malignant transformation of a pleomorphic adenoma may involve myoepithelial as well as epithelial elements. Accumulation of p53 protein, perhaps through mutational events, may have played a role in this malignant transformation.
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PMID:Myoepithelial carcinoma (malignant myoepithelioma) of the parotid gland arising in a pleomorphic adenoma. 1007 Mar 44

We describe the case of an 11-yr-old boy with a 2.5-cm-diameter soft tumor superficially located at the dorsal aspect of the tongue. Fine-needle aspiration cytology smears showed plump epithelioid cells with round to mildly oval nuclei and open chromatin. One or two nucleoli of intermediate size were noticed in each nucleus. These cells appeared singly or in small groups. The findings were interpreted as containing plasmacytoid cells coming from an adenoma of salivary gland origin. The histologic examination of the surgical specimen revealed noncohesive, pleomorphic polygonal cells combining plasmacytoid/rhabdoid cytoplasmic features, with mild to moderate nuclear pleomorphism. One mitotic figure was observed per 10 high-power fields. Immunoreactivity was strongly positive for vimentin and S-100 protein, less intense for the cytokeratins, and negative for smooth muscle actin, muscle-specific actin, myoglobin, and GFAP. No ultrastructural evidences of myogenous differentiation were found. We propose that this case represents an unusual atypical variant of plasmacytoid monomorphic adenoma.
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PMID:Atypical plasmacytoid monomorphic adenoma of salivary glands of the tongue: cytologic, histologic, immunohistochemical, and ultrastructural findings. 988 24

Alveolar adenoma of lung is a rare benign neoplasm of uncertain histogenesis. Its rarity hampers characterization of its epithelial and mesenchymal elements. Clinical and histopathologic features of 17 alveolar adenomas were reviewed. Histochemistry was performed on 10 cases, ultrastructural analysis on two, and immunohistochemistry on six cases for pneumocyte markers, thyroid transcription factor (TTF-1), surfactant protein markers pro-SP-B and pro-SP-C, and the Clara cell marker, CC10. Immunohistochemistry was performed in nine cases for desmin, smooth muscle actin, muscle-specific actin, cytokeratin, proliferating cell nuclear antigen (PCNA), factor VIII, and carcinoembryonic antigen. The mean age was 53 years. Seven cases occurred in men, and nine occurred in women. The age and sex were not known for one patient. The tumors were coin lesions on chest radiographs in asymptomatic patients except for one (cough). The mean size was 2.2 cm. The tumors were well demarcated with multiple cystic spaces containing granular material. Mostly type 2 pneumocytes lined the cystic spaces with fewer type 1 cells and no Clara cells. This was confirmed by staining for TTF-1, pro-SP-B, and pro-SP-C and by ultrastructure. CC10 was negative in all cases. The stroma varied from prominent spindle cells with a myxoid matrix to thin alveolar septa. The interstitial spindle cells resembled fibroblasts by immunohistochemistry and ultrastructure. Follow-up data available in five cases showed no recurrence at 2, 2, 5, 8, and 13 years. In summary, alveolar adenoma is a benign neoplasm consisting of an intimate admixture of alveolar epithelial and septal mesenchymal tissue. Most of the epithelial cells are type 2 pneumocytes, and the interstitial stromal cells are fibroblasts or fibroblast-like cells. Recognition of its characteristic morphological appearance allows for its distinction from other benign lesions of the lung.
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PMID:Alveolar adenoma: a histochemical, immunohistochemical, and ultrastructural analysis of 17 cases. 1002 43

Pleomorphic adenomas with a nuclear palisading arrangement of spindle-shaped modified myoepithelial cells (MMCs), suggesting the appearance of palisading leiomyoma or Antoni's A type of neurilemmoma, are quite rare, and its cytologic nature has been poorly understood. This paper reports histologic and immunohistochemical findings of palisading MMCs in two cases of pleomorphic adenoma. Histologically, foci of spindle-shaped MMCs with nuclei in a palisading arrangement were scattered in the myxoid areas. Near the large foci of spindle-shaped MMCs with nuclear palisading arrangements, tiny foci of spindle-shaped MMCs forming nuclear palisading or rosette-like arrangements were seen. Such nuclear palisading arrangements of MMCs were suggestive of differentiation or transformation of MMCs into cells that were more smooth muscle in nature, supported by occasional existence of palisading leiomyoma in the myometrium and gastrointestinal tract. However, immunohistochemical findings of palisading MMCs in pleomorphic adenoma were similar to those of non-palisading MMCs, and showed no evidence of smooth muscle differentiation; neither palisading nor non-palisading MMCs in pleomorphic adenoma expressed desmin, muscle specific actin (HHF-35), alpha smooth muscle actin, or myoglobin. The biologic significance and formative mechanism of nuclear palisading arrangement of MMCs in pleomorphic adenoma could not be determined in the present study. However, if the MMCs with nuclear palisading arrangements in pleomorphic adenoma, presented here, are aspirated for cytologic diagnosis or are included in a small biopsy specimen, the correct diagnosis of pleomorphic adenoma may be confused by a suspicion of myogenic or neurogenic tumor.
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PMID:Pleomorphic adenoma with nuclear palisading arrangement of modified myoepithelial cells: histopathologic and immunohistochemical study. 1052 75


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