Expression of epithelial markers in sarcomatoid carcinoma: an immunohistochemical study

Spindle epithelial tumor with thymus-like differentiation: a morphologic, immunohistochemical, and molecular genetic study of 11 cases

Spindle epithelial tumor with thymus-like differentiation (SETTLE) is an extremely rare tumor of the thyroid and neck, first described by Chan and Rosai. SETTLE is a low-grade malignancy, with potential for late lung, lymph node, and other visceral metastases. The clinicopathologic features of SETTLE overlap significantly with those of synovial sarcoma. Thirteen cases previously diagnosed as "SETTLE" (11 cases) or "malignant neoplasm-SETTLE versus synovial sarcoma" (2 cases), were retrieved. Immunohistochemistry for low-molecular-weight cytokeratins, high-molecular-weight cytokeratins, cytokeratin 7, cytokeratin 20, epithelial membrane antigen, bcl-2, CD34, CD99, CD117, INI-1, and TLE1 were performed. Reverse transcriptase polymerase chain reaction for the SS18/SSX1 and SS18/SSX2 fusion genes and fluorescent in-situ hybridization for SYT rearrangement was performed. The 11 cases diagnosed, as "SETTLE" were negative for synovial sarcoma-associated fusion genes, whereas the other 2 cases were positive. SETTLE occurred in 7 females and 4 males (7 to 50 y of age, median 13.5 y) and involved the thyroid gland in 10 cases. Clinical follow-up showed 3 patients to be disease-free 7, 10, and 15 years after surgery. One patient had a lymph node metastasis at diagnosis and lung metastases 14 months after diagnosis. SETTLE infiltrated the thyroid, and consisted of a vaguely nodular admixture of fascicular, reticular, hyalinized, and microcystic areas. Spindled zones blended imperceptibly into areas showing epithelial differentiation, in the form of glomeruloid glandular structures, sertoli-like tubules, and small glands, lined by cuboidal to columnar cells. Mitotic activity was very low, necrosis was absent, and pleomorphism was not present. By immunohistochemistry, SETTLE showed extensive expression of high-molecular-weight cytokeratins in 7 of 8 cases (88%). Expression of low-molecular-weight cytokeratins and epithelial membrane antigen was limited, confined to only scattered cells in 7 of 8 (88%), and 4 of 8 (50%) of cases, respectively. Cytokeratin 7 expression was more widespread (7 of 8 cases, 88%). Cytokeratin 20 was negative. Expression of CD99 and bcl-2 was seen in 6 of 8 (75%) and 7 of 8 (88%) cases, respectively. CD117, INI-1, and TLE1 expression was seen in 6 of 8 (75%), 8 of 8 (100%), and 1 of 5 (20%) of cases, respectively. We conclude that traditional morphologic study and a limited panel of ancillary immunostains are sufficient for the distinction of SETTLE from synovial sarcoma in almost all instances. Molecular genetic study may, however, be helpful in selected cases, particularly in limited biopsies.

Immunohistochemical p53 expression patterns in sarcomatoid carcinomas of the upper respiratory tract

Sarcomatoid carcinoma of the upper respiratory tract is a phenotypically complex neoplasm that has triggered much thoughtful discussion regarding histogenic origin and morphologic classification. In particular, its putative epithelial lineage and distinction from a pseudosarcomatous reaction are sometimes questioned. Little is known about the genetic alterations underlying sarcomatoid carcinoma. Although about 45% of conventional squamous cell carcinomas of the upper respiratory tract harbor p53 mutations, the p53 status of sarcomatoid carcinomas is not well established. p53 immunohistochemical analysis using the monoclonal antibody D07 was performed on 23 sarcomatoid carcinomas of the upper respiratory tract. Twenty tumors were biphasic, having dual epithelial and spindled components. In four of these biphasic tumors, the epithelial and spindled components were separately analyzed for p53 gene mutations by sequence analysis. p53 immunohistochemistry was also performed on 19 cases of postradiation stromal atypia. Strong and diffuse p53 staining was detected in 18 (78%) of the 23 sarcomatoid carcinomas. When the spindled component was compared with its corresponding epithelial component, identical patterns of p53 protein expression were noted in 19 (95%) of the 20 biphasic tumors. Weak p53 staining was observed in one (5%) of the 19 cases of postradiation stromal atypia. In the four biphasic tumors evaluated by DNA sequence analysis, p53 status was always the same in the paired epithelial and spindle cell components. These findings help further dispel the notion that sarcomatoid carcinoma represents a reactive spindle cell proliferation (pseudosarcoma) or a collision between a carcinoma and a sarcoma (collision tumor). Instead, the epithelial and spindled components share a common pathway of tumorigenesis despite their conspicuous divergence at the phenotypic level.

Sarcomatoid carcinoma of the urinary bladder: a clinicopathologic and immunohistochemical analysis of 14 patients

Sarcomatoid carcinoma of the urinary bladder is a rare entity, in which both the histogenesis and biological behavior remain controversial. We herein describe the clinicopathologic and immunohistochemical profiles of sarcomatoid carcinomas and discuss the significance of cell adhesion molecules in the development of this peculiar neoplasm. The authors examined formalin-fixed and paraffin-embedded tissue samples from 14 patients with sarcomatoid carcinoma of the urinary bladder. An immunohistochemical analysis was performed by using antibodies against epithelial and mesenchymal antigens as well as adhesion molecules. Most patients suffered from an advanced stage of the tumor, extending to the muscular layer (7 cases) or to the perivesical tissues (5 cases). Microscopically, all 14 tumors were composed predominantly of a carcomatoid component and an obviously carcinomatous component. The sarcomatoid component was composed of a mixture of spindle cells, round cells, and pleomorphic giant cells. The carcinomatous components consisted of papillary or nonpapillary high-grade transitional cell carcinoma (TCC). The zones of gradual transition between the carcinomatous and the sarcomatous elements were focally apparent in each tumor. The findings of an immunohistochemical examination indicated that both carcinomatous and sarcomatoid components expressed epithelial antigens (pankeratin or EMA), even though the staining pattern varied from case to case. As for cell adhesion molecules, the carcinomatous components were positive for E-cadherin (8 of 12), CD44s (8 of 12), and CD44v6 (6 of 12). Although the sarcomatoid components were also positive for E-cadherin (5 of 12), CD44s (4 of 12), and CD44v6 (3 of 12), these rates were lower than those in the carcinomatous components. Six patients died of their disease between 5 and 36 months after the diagnosis was made. The recognition of sarcomatoid carcinomas has important therapeutic and prognostic implications. It seems appropriate to treat these neoplasms in the same manner as conventional high-grade TCCs with similar degrees of invasion. We consider that sarcomatoid carcinomas should be regarded as a high-grade carcinoma that shows a prominent pseudosarcomatous dedifferentiation. The sarcomatoid component of sarcomatoid carcinomas may result from either anaplastic changes or dedifferentiation related to the process of losing cell adhesion molecules.

Spindle cell carcinoma of the larynx: review of 26 cases including DNA content and immunohistochemistry

Spindle cell carcinoma (SpCC) is uncommon, with a predilection for the upper aerodigestive tract. Its histogenesis has not been resolved, although most authors support the sarcomatoid carcinoma concept. Ploidy analysis and proliferation indices have not been reported for laryngeal SpCCs. The authors examined the pathological and clinical features of 26 patients (25 men, 1 woman; mean age, 64 years) with laryngeal SpCC treated at the Mayo Clinic from 1960 to 1990. Twenty-three tumors were examined with digital image analysis for DNA content of the spindle cell population (13 tumors had a sufficient squamous component to be analyzed separately). The glottis was involved most frequently (19 patients); 21 tumors were grossly polypoid. Twenty-three tumors were biphasic, and three were monophasic. Overall, 17 tumors (65%) showed keratin positivity in the spindle cell component. Polyclonal antikeratin (15 positive cases), 34betaE12 (15 positive), and AE1/AE3 (12 positive) were the most sensitive markers. Spindle cells were diploid in 5 tumors (22%) and nondiploid in 18 (78%); conventional squamous cell carcinoma was diploid in 4 cases and nondiploid in 9. DNA ploidy results were concordant between the two populations in 11 of 13 tumors (85%). Mean percent MIB-1 staining was 31% in the sarcomatoid component and 45% in the squamous component. In our primary treatment group of 22 patients (median follow-up, 6.4 years), 4 (18%) had local recurrence, 3 (14%) had distant metastasis, and 4 (18%) died of disease. Presence of a nondiploid spindle cell population in 78% of cases of laryngeal SpCC is interpreted as evidence of a neoplastic rather than reactive process. Keratin positivity in nearly two thirds of tumors supports the theory of epithelial origin of these tumors (sarcomatoid carcinoma).

Sarcomatoid carcinomas: pathological and histopathogenetic considerations

Malignant tumors with a mixed phenotype are a controversial field of pathology. In this article the morphological aspects and the immunohistological characterization of sarcomatoid carcinomas are presented. These uncommon neoplasms show both carcinomatous and sarcomatous features, and have been described in the past under a variety of different names causing great uncertainty about their classification and histogenesis. They can occur in various anatomical sites and exhibit a wide range of microscopic appearances, but some features are quite characteristic and are found in many cases. Morphological "transition" between carcinomatous and sarcomatous tissue, and detection of epithelial characteristics by electron microscopy or immunohistochemistry in the sarcomatous component, are very peculiar features of these neoplasms, providing both helpful clues for pathological diagnosis and important insights into histogenesis. Here a unifying histopathogenetic mechanism based on the phenotypic conversion of carcinoma into sarcomatoid tissue is proposed and supporting literature data from both experimental systems and clinicopathological observations are reviewed and discussed.

Sarcomatoid carcinoma: an ultrastructural study with light microscopic and immunohistochemical correlation of 10 cases from various anatomic sites

The histogenesis of sarcomatoid carcinoma has been an intriguing topic for pathologists for many years, and considerable evidence has accumulated in the fields of tissue culture, electron microscopy, and immunohistochemistry to support the concept that the sarcomatous cells derive by way of "divergent differentiation" (metaplasia) from the carcinomatous elements. We have studied a group of 10 cases of these tumors from various organs, using detailed ultrastructural analysis as well as light microscopic and immunohistochemical correlation. We found that there is an ultrastructural spectrum of differentiation from epithelial to mesenchymal type features and that the malignant spindle cells may be purely epithelial (3 cases), purely mesenchymal (3 cases), or a mixture of both (4 cases). Furthermore, individual cells may show biphasia, having desmosomes and tonofibrils as well as well developed rough endoplasmic reticulum and filaments with dense bodies. Electron microscopic and immunohistochemical results do not always correlate, illustrating the prudence of using several keratin antibodies, including wide-spectrum ones, and of performing electron microscopic examination on these tumors.

Spindle cell carcinoma of the parotid gland

Spindle cell carcinomas of the salivary gland are extremely rare, with only a few cases having been previously reported. We present a 55-year-old man with a rapidly enlarging mass in the left parotid gland. Despite radical surgery, the tumour recurred, and led to death 11 months later. Histopathologically, the tumour was composed of two components, a squamous cell carcinoma component and a spindle cell sarcomatoid component. A diagnosis of primary spindle cell carcinoma of the parotid gland was made. Immunohistochemical studies revealed keratin positivity and vimentin negativity in the squamous cell carcinoma component: the spindle cell sarcomatoid component was positive for vimentin and negative for keratin, but showed focal positivity for epithelial membrane antigen. The origin of the sarcomatoid component and the differential diagnosis from malignant mixed tumours are discussed.

Lung carcinoma with spindle cell components: sixteen cases examined by immunohistochemistry

Sixteen cases of lung carcinoma with spindle cell components were studied by conventional histochemistry and immunohistochemistry. The epithelial components were squamous cell carcinoma in six cases, adenocarcinoma in four, adenosquamous carcinoma in five, and large cell carcinoma in one. In every case sarcomatous areas were distinctly observed and, in general, neoplastic spindle cells proliferated in close proximity to the epithelial elements. Some of the histochemical procedures suggested mesenchymal features in the stroma of the exophytic portions of three cases, but heterogeneous elements, such as bone or striated muscle, were not observed. By immunohistochemical examination the epithelial elements showed positive reactions for keratin, epithelial membrane antigen, and/or carcinoembryonic antigen to a varying degree according to the histologic types. The spindle cell elements revealed a positive immunoreaction for keratin in all but one case. Epithelial membrane antigen was demonstrated in sarcomatous areas of only five cases and carcinoembryonic antigen was not expressed at all. In contrast, vimentin was distinctly demonstrated in sarcomatous areas of five cases, although other mesenchymal markers, such as desmin, actin, and myosin, were negative. These findings indicate that the spindle cell components in these 16 cases may represent mesenchymal features with partial or complete loss of epithelial features.

Sarcomatoid carcinoma of the prostate. A clinicopathologic study of 12 patients

Sarcomatoid carcinoma of the prostate is a rare tumor that can be difficult to distinguish from a true sarcoma. The authors report 12 patients in whom the typical light microscopic appearance of prostatic adenocarcinoma was accompanied by the appearance of spindled or pleomorphic sarcomatoid areas within the same specimen or in subsequent accessions. Immunostaining or electron microscopic study demonstrated epithelial differentiation within the sarcomatoid area(s) in 6 of the 11 patients in whom special studies were performed. All nine patients for whom follow-up data were available died of disease within 3 to 48 months (median time until death, 12.0 months) after the appearance of the sarcomatoid carcinoma, and the clinical course in each instance was characterized by aggressive local recurrence. Our experience confirms that sarcomatoid carcinoma of the prostate is an aggressive variant of prostatic adenocarcinoma.

Transitional cell carcinoma with sarcomatous elements in the urinary tract. Six cases examined by immunohistochemistry

We report six cases of carcinoma showing sarcomatous change in the urinary tract examined by conventional histochemistry and immunohistochemistry. All of the cases were transitional cell carcinoma with or without focal squamous cell carcinoma. Sarcomatous components resembling spindle cell sarcoma with a marked myxoid stroma or chondrosarcomatous element were also observed in all cases. The sarcomatous elements were closely associated with the areas of squamous cell carcinoma in three cases. Various histochemical staining procedures demonstrated mesenchymal features in the stroma of sarcomatous areas. By immunohistochemical examination, the epithelial components showed positive reactions for keratin, epithelial membrane antigen and, focally, carcinoembryonic antigen. The sarcomatous components revealed a positive immunoreaction for keratin but lacked other epithelial markers in all cases. Chondrosarcomatous elements in two cases were positive for both keratin and S-100 protein. These findings indicate that sarcomatous elements in carcinoma may represent mesenchymal metaplasia with partial or complete loss of epithelial features. However, further study will be necessary in order to determine whether heterogeneous elements, such as chondrosarcomatous areas, are epithelial or truly mesenchymal in origin.

The expression of intermediate filaments and mam-6 antigen in relation to the degree of morphologic differentiation of carcinoma of the head and neck: diagnostic implications

In this study, the immunoreactivity of several cytokeratin antibodies; 115 D8, a monoclonal antibody against MAM-6, an epithelial membrane antigen; and two vimentin antibodies, is examined in relation to the degree of morphologic differentiation in carcinomas of the head and neck. The results indicate that a relationship exists between the degree of morphologic differentiation and the expression of cytokeratin, MAM-6, and vimentin, as detected by polyclonal antikeratin, 115 D8 and anti-vimentin. Expression of cytokeratin and MAM-6 is reversely related to vimentin. Polyclonal anti-keratin; CAM 5.2, a monoclonal antibody against cytokeratin 8, 18 and 19; and 115 D8, used in combination, were still able to identify the epithelial nature of undifferentiated/spindle cells. Since these immunohistochemical markers precede light microscopic detectable signs of epithelial differentiation, they can be used for the identification of the epithelial nature of undifferentiated/spindle tumors of the head and neck.