Myoepithelial carcinoma (malignant myoepithelioma) of the parotid gland arising in a pleomorphic adenoma.

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.     

Invasive carcinoma arising from a colonic adenoma with clear cell change

Clear cell change (CCC) in colonic adenoma is rare, and its biological and clinical significance remains unknown. Malignant progression of an adenoma with CCC has seldom been reported. We report a case of a sigmoid adenoma with multiple foci of CCC associated with high-grade dysplasia and invasive carcinoma in a 62-year-old patient. We evaluated the histochemical and immunohistochemical characteristics of each component of the adenoma. In contrast to other parts of the adenoma, p53 was strongly and diffusely overexpressed in the areas of CCC, high-grade dysplasia, and carcinoma. The MIB-1 labeling index was also significantly higher in these components than in other parts of the adenoma. In conclusion, our findings suggest that CCC in adenoma may be associated with malignant progression of the adenoma. Hence, for practical purposes, we recommend considering CCC in colonic adenomas as a high-grade dysplasia equivalent and following up the patient accordingly.     

Epithelial-myoepithelial carcinoma of the parotid gland in a child.

A rare case of epithelial-myoepithelial carcinoma of the parotid gland, which occurred in a child, is reported. An 8-year-old boy presented with swelling of the right parotid gland. He underwent total parotidectomy followed by irradiation for a parotid gland tumor. Three years after the operation, a recurrent tumor invading the base of the skull and the brain and metastases in the lung were noted. The patient expired in spite of extirpation of the intracranial recurrent tumor. The resected tumor showed a characteristic histologic feature: double-layered tubular structures composed of inner dark cells (epithelial cells) and outer clear cells (myoepithelial cells). This patient may be the youngest one with the epithelial-myoepithelial carcinoma reported in the literature.     

Metastatic renal cell carcinoma,clear cell type,of the parotid gland

Renal cell carcinoma (RCC), clear cell type, is a commonly encountered metastatic tumor that can present at unusual anatomic sites many years after the primary tumor resection. Noncutaneous metastasis to the parotid gland is unusual; however, a number of cases of parotid RCC metastasis have been reported. Fine‐needle aspiration biopsy (FNAB) is regularly utilized during the evaluation of salivary gland lesions, where it has a high sensitivity, specificity, and accuracy; however, the identification and definitive diagnosis of primary and metastatic clear cell neoplasms is a potential diagnostic pitfall for salivary gland FNAB. Here, we describe a case of RCC, clear cell type, metastatic to the parotid gland that was diagnosed entirely from FNAB cell block material, which is the first such reported case to our knowledge. We review the literature for cases of parotid RCC metastasis and focus on the utility of FNAB for synchronous versus metachronous presentations. Finally, we evaluate the differential diagnosis of clear cell parotid lesions, including ancillary histologic studies, and propose an algorithmic approach to clear cell neoplasms of the salivary gland. Diagn. Cytopathol. 2014;42:974–983. © 2014 Wiley Periodicals, Inc.     

Glycogen-rich clear cell carcinoma arising from minor salivary glands of the uvula. A case report

Glycogen-rich clear cell carcinoma arising from minor salivary glands of the uvula in a 35-year-old woman is reported. This tumor was composed of nests and cords of clear cells containing cytoplasmic glycogen but no mucin. The epithelial nature of this lesion was obvious because of positive immunoreactivity for cytokeratin and epithelial membrane antigen, and the presence of immature lumina and intercellular spaces lined by many microvilli, associated with desmosomal junctions and basal lamina, as revealed by ultrastructural study. However, no myoepithelial cells could be detected. From these findings, it may be concluded that this tumor corresponds to glycogen-rich clear cell carcinoma (a variant of clear cell tumor), revealing glandular differentiation.     

Dedifferentiated malignant myoepithelioma of the parotid gland

Dedifferentiated salivary gland tumor is a rare, recently recognized tumor type. A case of dedifferentiated malignant myoepithelioma in a 59-year-old man who presented with a painful mass in the left preauricular region is reported. Histologically, two distinct neoplastic cell populations were observed in the same tumor mass. The first population was composed of solid nests of polygonal eosinophilic or glycogen-rich clear cells showing neoplastic myoepithelial immunocytological features, such as positivity for cytokeratins, vimentin, S-100 protein (S-100), alpha-smooth muscle actin (SMA) and glial fibrillary acidic protein (GFAP). A multinodular growth pattern, necrosis and occasional mitotic figures suggested malignancy. This population was diagnosed as low-grade malignant myoepithelioma. The second population infiltrated diffusely into the parotid gland and facial nerves. It consisted of polygonal or short spindle cells with obvious pleomorphism and atypical mitoses. The tumor cells were positive for vimentin and cytokeratins, and showed an accumulation of p53 and cyclin D1. S-100 protein, SMA and GFAP were negative. This population was regarded as undifferentiated carcinoma. A final diagnosis of dedifferentiated malignant myoepithelioma was made. This seems to be the first published case of dedifferentiation in malignant myoepithelioma. Because any tumor type can undergo dedifferentiation with accumulation of additional genetic changes, complete sampling should be the standard approach to all salivary gland tumors in order to avoid missing a dedifferentiation component.     

Hurthle cell carcinoma arising from thyroid papillary carcinoma

Hürthle cell carcinoma of the thyroid is generally considered to be a subtype of follicular carcinoma. We report a case of a small solitary usual-type papillary carcinoma of the thyroid, with metastatic tumor in cervical lymph nodes. The lymph node tumor consisted of both tall-cell papillary carcinoma and Hürthle cell carcinoma. This suggests a closer relationship between papillary cell carcinoma and Hürthle cell tumors than previously appreciated.     

Mucoepidermoid carcinoma arising in Warthin's tumor of the parotid gland

Malignant transformation of Warthin's tumor is extremely rare, although it is the second most common benign tumor of the parotid gland. We describe our experience of mucoepidermoid carcinoma arising in Warthin's tumor of the parotid gland in a 64-year-old man. He had a swelling in the left parotid-masseteric region. The removed tumor was well encapsulated and histopathologically comprised Warthin's tumor and low-grade mucoepidermoid carcinoma. The mucoepidermoid carcinoma infiltrated lymphoid stroma of the Warthin's tumor, but capsular invasion is not found. Considering the clinical course and physical examination, the lesion was diagnosed as mucoepidermoid carcinoma arising in Warthin's tumor because its features filled the criteria of malignant transformation of Warthin's tumor. There has been no recurrence or distant metastasis for 19 months. Histological change from Warthin's tumor to mucoepidermoid carcinoma may be implicated in squamous or goblet cell metaplasia of epithelial cells. It is considered that the neoplastic cells of Warthin's tumor acquire malignant genotypes simultaneously with this dual differentiation.     

Micropapillary carcinoma of the parotid gland arising in mucinous cystadenoma

We describe a 45-year-old man who had a 2-year history of a slowly enlarging tumor in the left parotid gland. Histologically, the tumor was a mucinous cystadenoma with focal apocrine differentiation, which revealed a widespread invasive micropapillary adenocarcinoma component. A rim of lymphoid tissue surrounded the margins of the micropapillary carcinoma. The invasive micropapillary adenocarcinoma component was morphologically identical with the invasive micropapillary carcinoma of the mammary gland. The tumor is different from so-far recognized salivary gland tumor entities. Received: 25 October 1999 / Accepted: 13 June 2000     

Epithelial-myoepithelial carcinoma arising in the nasal cavity: a case report and review of literature.

Epithelial-myoepithelial carcinoma is an uncommon, low-grade, malignant epithelial neoplasm composed of variable proportions of ductular cells and large, clear staining, myoepithelial cells arranged around the periphery of the ducts. About 120 cases have been reported in the world literature, most of which were located in salivary glands, except for a few cases occurring in unusual locations such as breast, lacrimal gland, nose, paranasal sinus, trachea, bronchus, and lung. We here reported the second case of epithelial-myoepithelial carcinoma of the nasal cavity with extension to the nasopharynx. The patient was a 61 year old Chinese female with two month's history of progressive nasal obstruction. Histopathologically, the tumor showed typical myoepithelial and ductal cells biphasic differentiation, duct-like structure and infiltrating growth pattern. Some ductal cells showed the characteristics of oxyphilic cell, which had never been reported before. Recurrence and metastasis rates of epithelial-myoepithelial carcinoma varied from 35% to 50% and 8.1% to 25% respectively in different reports. The present case had neither recurrence nor metastasis twenty months after operation. When epithelial-myoepithelial carcinoma is mainly composed of spindle myoepithelial cells, the differential diagnosis should include myoepithelioma, neurofibroma, leiomyoma and hemangiopericytoma.     

伴玻璃样间质的透明细胞癌二例

例1男,76岁。因双下肢浮肿2个月余,声嘶1周于2000年3月12日入院。体检:一般情况差,左颈部触及肿大淋巴结约2cm×2cm大小,血生化检查提示肾功能及呼吸功能衰竭,后因呼吸困难作气管插管时舌根部见一菜花状肿瘤约3.0cm×2.5cm大小,行颈淋巴结及舌根部肿瘤活检术。术后1个月患者死于慢性肾炎所致肾功能及呼吸功能衰竭。病理检查:切除淋巴结大小2cm×2cm,切面灰白色,质硬。舌根部肿瘤大小3.0cm×2.5cm,表面呈菜花状,切面灰白色,质硬。镜下观察:舌根部肿瘤细胞形态较一致,排列呈互相吻合的小梁状、岛状或片状。巢间有大量玻璃样变的纤维性间质。瘤…     

Clear cell papillary renal cell carcinoma and clear cell renal cell carcinoma arising in acquired cystic disease of the kidney: an immunohistochemical and genetic study

Clear cell papillary renal cell carcinoma (RCC) is a recently established disease entity. However, there are few reports on genetic study of this entity. We report such a case with focus on genetic study. A 57-year-old Japanese man was found to have 3 renal tumors. Histologically, two tumors showed findings of clear cell RCC; and the other tumor showed findings of clear cell papillary RCC that was characterized by papillary growth pattern of neoplastic cells in cystic space with purely clear cell cytology. Immunohistochemically, tumor cells of clear cell papillary RCC were diffusely positive for PAX2 and cytokeratin 7, but negative for CD10, RCC Ma, and AMACR. In fluorescence in situ hybridization study for one clear cell papillary RCC, we detected polysomy for chromosome 7 and monosomy for chromosomes 17, 16, and 20. In addition, we detected mutation of VHL gene in clear cell RCC, but found no VHL gene mutation in clear cell papillary RCC. Finally, our results provide further evidence that clear cell papillary RCC may be both morphologically and genetically distinct entity from clear cell RCC and papillary RCC.