Hepatoblastomas: an ultrastructural and immunohistochemical study.

Seven hepatoblastomas were studied by electron microscopy, and four of these were studied by immunohistochemistry. Five tumors were purely epithelial, and two were mixed epithelial-mesenchymal. They showed a spectrum of cellular differentiation ranging from primitive epithelial cells to differentiated cells resembling adult hepatocytes. Glycogen, lipid, basal lamina, and canaliculi were present in all cases. Mitochondria with large, membrane-bound, amorphous inclusions were present in one tumor, and large, complex, basal cell processes were present in two tumors. Ultrastructural features most characteristic of hepatocytes were most common in fetal type hepatoblastomas. Immunoreactive chromogranin cells were present in two tumors, one of which also contained immunoreactive somatostatin cells. The somatostatin-positive tumor had cells with granules resembling those seen in somatostatin-containing cells of normal pancreas and somatostatin-containing neuroendocrine carcinomas. Other immunoreactive substances were present, including alpha 1-antitrypsin (four cases), vimentin (embryonal cells in four cases; fetal cells in three cases), low-molecular weight cytokeratin (embryonal cells in three cases; fetal cells in four cases), and high-molecular weight cytokeratin (embryonal cells in one case; fetal cells in two cases). Osteoidlike material was positive for epithelial membrane antigen, vimentin, and S-100 protein.     

Hepatoblastoma: an immunohistochemical and ultrastructural study

The ultrastructural and immunohistochemical features of 19 hepatoblastomas were examined to evaluate the phenotypic expressivity of this solid embryonic neoplasm of childhood. Electron microscopy confirmed the embryonal and fetal characteristics of the neoplastic hepatocytes, but in addition, cells with features intermediate between these two cell types were identified. Dense bundles of collagen corresponding to the osteoid-like material by light microscopy surrounded nests of cells; the cells within this matrix stained for epithelial membrane antigen and vimentin and focally for cytokeratin, and they showed ultrastructural features of epithelial cells. The two cases of small cell hepatoblastoma reacted positively for vimentin and cytokeratin; the remaining 17 cases were immunoreactive for cytokeratin and alpha-fetoprotein, and some also for alpha 1-antitrypsin, ferritin, and vimentin. A histogenetic scheme based on our findings is proposed to explain the divergent morphologic features of this neoplasm.     

Fine needle aspiration biopsy cytology of hepatoblastoma

Fine needle aspiration biopsy (FNAB) from four patients with histologically proven hepatoblastoma (HB) is reviewed. Patient ages ranged from 5 mo to 19 mo; two were male and two were female. Initial cytologic diagnoses were hepatoblastoma in two cases, malignant neoplasm consistent with liver cell tumor in one case, and probable Wilm's tumor in a fourth case. Cytologic features were similar in all cases and included highly cellular smears composed of a uniform population of small to intermediate sized round to oval cells. Extramedullary hematopoietic cells were obvious in smears of one patient. Neither bile nor extracellular stroma was seen. Immunohistochemical stains performed in two cases demonstrated positive staining for low-molecular-weight cytokeratins expressing polypeptides 8 and 18 of the Moll classification. Staining for vimentin, carcinoembryonic antigen, and epithelial membrane antigen was negative. alpha-Fetoprotein and alpha 1-antitrypsin stains were equivocal because of high background staining. Electron microscopy from three cases showed cells with features of immature hepatocytes. Three tumors were subsequently examined histologically by surgical biopsy, and one at autopsy. All were epithelial-type HB containing a mixture of "fetal" and "embryonal" hepatocytes. These results demonstrate the successful mimicry of FNAB cytology of hepatoblastoma to its histologic counterpart and its clinical utility in the diagnosis of intrahepatic masses of children.     

Intermediate filament proteins in human testis and testicular germ-cell tumors

Normal testicular tissue and 76 testicular germ-cell tumors of various types were immunohistochemically evaluated for the expression of intermediate filament proteins of different types. In normal testes, the rete testis epithelium was positive to cytokeratin, and the Sertoli cells, stromal cells, and Leydig cells were positive for vimentin. Cytokeratin-positive cells were also found lining atrophic seminiferous tubules and were occasionally seen within nonatrophic seminiferous tubules. The classical seminomas showed vimentin positivity, but this was usually observed in a small number of tumor cells. In addition, nearly half the seminomas contained single cytokeratin-positive cells, some of which were multinucleated and appeared to represent syncytiotrophoblastic giant cells. The tumor cells in embryonal carcinomas, endodermal sinus tumors, and choriocarcinomas displayed cytokeratin positivity. In some embryonal carcinomas vimentin-positive tumor cells were also found, probably representing attempts at further differentiation of the tumor cells. In immature teratomas, both the immature and the mature epithelial structures showed cytokeratin positivity. The stromal components, including cartilage, contained vimentin, and the smooth-muscle elements, desmin. Neural tissue positive for neurofilaments and glial tissue positive for glial fibrillary acidic protein, were observed in 5 and 3 of 15 cases, respectively. It is considered that antibodies to intermediate filaments are suitable tools to characterize the differentiation patterns of testicular germ-cell tumors and have the potential to aid in the differential diagnosis especially between seminoma and embryonal carcinoma.     

Pulmonary blastoma. An immunohistochemical analysis with comparison with fetal lung in its pseudoglandular stage

Pulmonary blastomas are believed to be mixed epithelial and mesenchymal tumors that recapitulate the developing lung at 10-16 weeks gestation. The authors compared nine blastomas with ten fetal lungs in the pseudoglandular stage of development with a panel of antibodies to various lung antigens to evaluate immunophenotypic homology. Both blastomas and embryonal lungs showed expression of cytokeratin, epithelial membrane antigen, and carcinoembryonic antigen in their epithelial elements, and both contained scattered chromogranin-positive neuroendocrine cells. Rare surfactant-producing and Clara cell antigen-elaborating cells were identified in both groups. The mesenchymal components of blastomas and fetal lung showed smooth muscle, myofibroblastic, and blastematous differentiation. The blastematous elements demonstrated vimentin and keratin coexpression in four cases, providing some support for the contention that pluripotential blastema may give rise to the epithelial and mesenchymal elements of the distal lobule.     

Pulmonary blastomas. Immunohistochemical investigations of three cases

Three cases of pulmonary blastoma (PB) were investigated microscopically with conventional stainings and immunohistochemically with monoclonal antibodies to cytokeratin, vimentin, desmin and neurofilament protein. The tumors differed in terms of morphology as well as of immunohistochemistry. Two were epithelial and mesenchymal mixed tumors, and the remaining one was a monophasic tumor of a typical blastemic character. The two mixed tumors also differed from each other. In one of them, the epithelial and mesenchymal component expressed cytokeratin and vimentin in a clear-cut manner without any transition. The other mixed tumor displayed a gradual epithelial-to-mesenchymal transition accompanied by a switch in the expression of cytokeratin and vimentin. The third tumor was of pure mesenchymal origin, expressing vimentin in the majority of cells and desmin in few cells. It is concluded that the PB is a morphologically and histogenetically heterogeneous tumor. Metaplastic changes may take place within a PB and make the recognition of embryogenesis more difficult.     

Uterine tumors resembling ovarian sex cord tumors are polyphenotypic neoplasms with true sex cord differentiation.

In this study, we present the clinicopathologic features and immunophenotypic characteristics of five cases of uterine tumors resembling ovarian sex cord tumors and three cases of endometrial stromal tumors with sex cord-like elements, with emphasis on immunohistochemical markers of sex cord differentiation. The mean patient age was 42 years (range 19-69 years), and vaginal bleeding was the most common clinical presentation. The tumors were usually polypoid masses arising in the uterine fundus, with a mean tumor size of 6.7 cm. Sex cord patterns in uterine tumors resembling ovarian sex cord tumors, including anastomosing cords, trabeculae, small nests, tubules, and in one case, a striking retiform architecture with Leydig-like cells, comprised from 70 to 100% of the tumor volume. All uterine tumors resembling ovarian sex cord tumors were positive for two or more markers of sex cord differentiation; all five cases showed strong immunoreactivity for calretinin, with coexpression of CD99 (four cases), Melan-A (two cases), and inhibin (two cases). Endometrial stromal tumors with sex cord-like elements were less frequently positive for markers of sex cord differentiation, with each case positive for one marker (calretinin, two cases; CD99, one case). In addition, all eight cases were frequently positive for cytokeratin, CD10, vimentin, estrogen receptor, and progesterone receptor; desmin immunoreactivity, when present, was limited to minor foci of smooth muscle. Overall, the morphologic and immunohistochemical findings in uterine tumors resembling ovarian sex cord tumors strongly support that these unusual uterine tumors are polyphenotypic neoplasms with true sex cord differentiation.     

Immunohistochemical analysis of embryonal sarcoma of the liver.

Embryonal sarcoma of the liver is a rare, aggressive malignant tumor that typically occurs in children and teenagers. Microscopic features include spindle, oval, or stellate cells with poorly defined cell borders, nuclear pleomorphism and multinucleation, and variable immunoreactivity to cytokeratin, vimentin, and alpha-1-antitrypsin. Intracellular and extracellular PAS-positive, diastase-resistant hyaline globules are commonly present. The authors evaluated a panel of IHC stains to better define the pattern of immunoreactivity in this tumor. Embryonal sarcomas of the liver were identified from archival files and were immunostained with antibodies: cytokeratin AE1/3, hepatocyte, SMMS, myogenin, calponin, h-caldesmon, desmin, S100, vimentin, CD34, C-kit (CD117), CD10, ALK-1, PE10, Bcl2, p53, and Ki-67. Six cases were identified. Patient age ranged from 6 to 24 years. Tumors ranged from 10 to 20 cm and contained spindled and epithelioid areas with PAS-positive, diastase-resistant globules and atypical cells with focal multinucleation. All cases showed immunoreactivity with vimentin and five showed immunoreactivity with Bcl2. Focal immunoreactivity was seen with cytokeratin AE1/3 in three cases, CD10 in four, calponin in two, desmin in one, and p53 in four. All tumors were negative with hepatocyte, myogenin, CD34, SMMS, h-caldesmon, PE10, ALK-1, and S100. No cytoplasmic staining was seen with C-kit. The proliferation index ranged from 30% to 95%. The diagnosis of embryonal sarcoma is based on typical morphologic features in a large liver tumor occurring in a young patient. The most useful IHC stains help to exclude tumors such as hepatoblastoma, hepatocellular carcinoma, embryonal rhabdomyosarcoma, and other sarcomas.     

Utility of immunohistochemistry in distinguishing ovarian sertoli-stromal cell tumors from carcinosarcomas.

Poorly differentiated Sertoli-stromal cell tumors and carcinosarcomas of the ovary both show biphasic epithelial and stromal patterns and may both show heterologous stromal elements, presenting a difficult diagnosis. We studied the immunohistochemical profile of Sertoli cell differentiation in human testes and applied these findings to the ovarian tumors. Eleven Sertoli-stromal cell tumors, six carcinosarcomas of the ovary, and 11 testes (six fetal, one infant, and four adult) were studied using antibodies to cytokeratin AE1:AE3 (AE1:3), cytokeratin CAM 5.2 (CAM), epithelial membrane antigen (EMA), vimentin, desmin, muscle-specific actin (MSA), S-100 protein (S-100), CA 19-9, CA 125, carcinoembryonic antigen monoclonal (CEA-M), carcinoembryonic antigen polyclonal (CEA-P), and placental alkaline phosphatase (PLAP). In the fetal testes, immature gonadal stroma and sex cord areas stained with vimentin (six of six cases), AE1:3 (five of six cases), and CAM (six of six cases). Sertoli cells in immature gonadal stroma areas, sex cords, and seminiferous tubules of normal fetal, infant, or adult testes never showed immunoreactivity for EMA, S-100, CA 19-9, CA 125, CEA-M, CEA-P, or PLAP. All Sertoli-stromal cell tumors stained with AE1:3 and CAM in areas of Sertoli cell differentiation (11 of 11 cases) but did not stain with EMA, PLAP, CEA-P, CEA-M, CA 19-9, CA 125, or S-100 (none of 11 cases). Carcinosarcomas expressed AE1:3 and CAM in all epithelial areas (six of six cases) and most stromal areas (five of six cases). Carcinomatous areas of carcinosarcoma also showed immunoreactivity for EMA (six of six cases), CA 125 (two of six cases), PLAP (two of six cases), CEA-P (two of six cases), and CEA-M (one of six cases), while stromal areas of carcinosarcoma expressed EMA (four of six cases) and S-100 (four of six cases). Heterologous stromal elements were present in three of 11 Sertoli-stromal cell tumors (two showed skeletal muscle and one showed both skeletal muscle and cartilage differentiation) and in four of six carcinosarcomas (one skeletal muscle, one cartilage, and two cartilage and skeletal muscle). All skeletal muscle heterologous elements expressed desmin, vimentin, and MSA. The heterologous cartilage in carcinosarcoma stained with S-100 (three of three), while the one case of heterologous cartilage in Sertoli-stromal cell tumor did not. These results suggest that ovarian Sertoli-stromal cell tumor can be distinguished from carcinosarcoma by the absence of staining for EMA, PLAP, CEA, CA 125, or CA 19-9 in epithelial areas of Sertoli-stromal cell tumor.(ABSTRACT TRUNCATED AT 400 WORDS)     

Myogenic expression in esophageal polypoid tumors

Four cases of esophageal polypoid tumors composed of squamous cell carcinoma and spindle cell sarcomatous components were investigated. Squamous cell carcinoma was consistently present in the base of the polypoid lesions in all four cases and was also intermingled with spindle-shaped sarcomatous cells in two cases. Metastases in the lymph nodes were observed in two cases: one was squamous cell carcinoma with a sarcomatous component and the other consisted of a pure sarcomatous component. All tumors involved at least the muscularis mucosae. In the sarcomatous region, the tumor was composed of highly anaplastic cells with or without forming interlacing fascicles. Pleomorphism was marked and bizarre giant cell forms were frequent. Mitoses were frequently present. Immunohistochemical study revealed that the anaplastic cells in the sarcomatous component in all cases were immunoreactive to desmin, muscle actin, vimentin, and alpha 1-antichymotrypsin, but were negative for cytokeratin, even in the metastatic tumors of the lymph nodes. The immunohistochemical results favor myogenic differentiation of the anaplastic cells, and these tumors were considered to be true carcinosarcomas composed of squamous cell carcinoma and leiomyosarcoma.     

Epithelial differentiation in medulloblastoma: comparison with other embryonal tumors of neuroectodermal origin

Three cases of medulloblastoma characterized by epithelial differentiation are described in patients 6-months-, 1-month- and 8-years-old. Histologically, tumors from the two infant patients showed a perivascular arrangement without apparent radiated cytoplasmic processes from the vessels. Tumor cells displayed round and/or pleomorphic vesicular nuclei and a more abundant eosinophilic cytoplasm than that found in classic medulloblastoma. Neither Homer-Wright rosettes nor ependymal or ependymoblastic rosettes were noted in these tumors. The tumor in the 8-year-old patient exhibited a classic medulloblastoma component intermingled with abundant eosinophilic cytoplasm forming a tubular structure. Immunohistochemically, tumor cells in all cases were positive for cytokeratin, synaptophysin, and vimentin. In the third case involving the 8-year-old patient, epithelial tumor cells were positive for cytokeratin, whereas classic medulloblastoma components were negative for cytokeratin. Positive staining for melanoma-specific antigen was seen only in the third case, where strong reactivity of tumor cells formed a tubulus. However, the classic medulloblastoma component was negative for melanoma-specific antigen. Ultrastructurally, basal laminae were observed around tumor cells in the 6-month-old patient. These morphological and immunohistochemical features suggest that medulloblastoma with epithelial differentiation is a rare but distinct variant of medulloblastoma, and that some of these tumors should show differentiation in ocular pigment epithelium.     

Extracellular matrix in hepatoblastoma: an immunohistochemical investigation

Eleven hepatoblastomas of various subtypes and normal liver tissue were investigated with antibodies against collagen types I-VI, laminin, fibronectin and endothelial and macrophage-associated antigens. Epithelial hepatoblastoma cells, unlike non-neoplastic hepatocytes, exhibited intracellular immunoreactivity for various extracellular matrix proteins (depending on the subtype: laminin, fibronectin and collagen types III, IV and V). The intracellular expression of extracellular matrix proteins by the tumour cells increased from the fetal subtype, through the embryonal subtype, to the small cell subtype. The epithelial tumours exhibited sinusoid-like blood vessels in numbers that varied according to the subtype. These contained Kupffer cells and exhibited greater amounts of the basement membrane components collagen type IV and laminin in the perisinusoidal space than those in the normal liver. The small cell hepatoblastoma exhibited smaller numbers of sinusoids, pronounced intracellular expression of extracellular matrix proteins and large numbers of fibres immunoreactive for collagen type III. In the mixed hepatoblastomas, the extracellular matrix of the osteoid was most strongly immunoreactive for collagen type I and that of the spindle cell areas for collagen type III.     

FNAC Aided Diagnosis and Categorization of Hepatoblastoma:

Hepatoblastoma is the most common primary malignant hepatic tumour of infancy and early childhood. Histologically hepatoblastomas are categorized into pure epithelial and mixed epithelial‐mesenchymal types and epithelial type is further subcategorized into pure fetal type, fetal and embryonal type, pure embryonal, and small cell types. This categorization has been shown to have prognostic and therapeutic implication. Fine needle aspiration cytology (FNAC) is useful in pre‐operative diagnosis and categorization in most cases of hepatoblastomas. Periodic acid–Schiff (PAS) stain can be helpful to differentiate fetal subtype from embryonal subtype of hepatoblastoma. Here we describe three cases of hepatoblastomas diagnosed and categorized on cytology with subsequent confirmation on histological examination. Diagn. Cytopathol. 2017;45:77–82. © 2016 Wiley Periodicals, Inc.     

A cytokeratin-immunohistochemical study of hepatoblastoma.

Six cases of hepatoblastoma (five epithelial, one mixed epithelial-mesenchymal) were studied on serially cut cryostat sections, using a panel of monoclonal antibodies directed against individual cytokeratins, vimentin, and desmin, in an indirect immunoperoxidase procedure. Embryonic and fetal-type tumor cells expressed the "hepatocellular" cytokeratins no. 8 and 18 but, surprisingly, also expressed the "bile duct type" cytokeratin no. 19. In addition, two cases had a number of tumor cells which were also positive for the "bile duct type" cytokeratin no. 7. Cells embedded in osteoid-like material were immunoreactive for vimentin but also for cytokeratins no. 7, 18, and 19. Gel electrophoresis, and Western blotting of cytoskeletal extracts, confirmed the immunohistochemical data. The implications of these findings for the histogenesis of hepatoblastoma are discussed in this report.     

Immunohistochemical demonstration of H antigen, peanut agglutinin receptor, and Saphora japonica receptor expression in infant thymuses and thymic neoplasias.

Ten infant thymuses and 13 primary thymic tumors obtained from archived paraffin-embedded tissue were examined for the presence of tissue blood group O antigen (H), peanut agglutinin receptor antigen (PNA-r), Saphora japonica agglutinin receptor antigen (SJA-r), carcinoembryonic antigen (CEA), cytokeratin (CK), and epithelial membrane antigen (EMA). In the thymuses studied, Hassall's corpuscles contained abundant immunoreactive CK, PNA-r, and H antigens, whereas CEA, SJA-r, and EMA were present focally in Hassall's corpuscles. Immunoreactive CK, PNA-r, and CEA were demonstrated focally in the subcapsular region, cortical nurse cells, and subcapsular-perivascular monocytic cells, respectively. PNA-r was present in all 12 epithelial type tumors, including all eight thymomas. CEA was present in nine tumors, including six thymomas. Six thymomas contained H antigen and SJA-r; five continued CK and EMA. SJA-r and EMA were also present in one carcinoid tumor of thymic origin. In epithelial thymomas, the antigens stained nests of epithelial cells resembling the pattern of staining in Hassall's corpuscles. Membrane staining of spindle cells of both spindle cell and epithelial thymomas was less intense than staining of epithelial type cells.     

Small epithelial cells and the histogenesis of hepatoblastoma. Electron microscopic, immunoelectron microscopic, and immunohistochemical findings.

The wide range of epithelial and mesenchymal lines of differentiation seen in hepatoblastoma suggests that this tumor derives from a pluripotent stem cell. To test this hypothesis, seven hepatoblastomas of various subtypes were investigated for the presence of cells with the features of the oval cells found during hepatocarcinogenesis in rodents that are thought to be closely related to hepatic stem cells. Because similar cells, referred to as "small cells," have been described in human liver disease with chronic ductular reaction, five liver biopsies from infants with biliary atresia were also investigated. The specimens were investigated by electron microscopy, immunoelectron microscopy, and immunostaining for cytokeratins 7, 8, 18, and 19. Small epithelial cells (SEC) corresponding to the oval cells of the rat and the "small cells" in humans were found in both biliary atresia and hepatoblastoma. These cells were oval and exhibited intercellular junctions, tonofilament bundles, and a biliary epithelium-type cytokeratin profile. SEC were found in small numbers in fetal hepatoblastoma and in moderate numbers in embryonal hepatoblastoma. In small cell hepatoblastoma, nearly all the tumor cells exhibited SEC-like ultrastructural features and a corresponding cytokeratin profile. Thus, cells exhibiting morphological and immunophenotypic features of hepatic stem cells are detectable in hepatoblastoma. Their numbers vary according to the subtype, reflecting the differing degrees of differentiation of the various subtypes, consistent with the theory propounded in the literature that embryonal and, with further differentiation, fetal tumor cells derive from precursor small cells. The findings support the hypothesis that hepatoblastoma derives from a pluripotent, probably entodermal or even less committed, stem cell.     

CLEAR CELL SARCOMA OF THE KIDNEY An Immunohistochemical Study

Three cases of clear cell sarcoma of the kidney (CCSK) and 5 cases of Wilms' tumor were investigated immunohistochemically to examine the expression of tissue-specific intermediate filaments (cytokeratin, vimentin, and desmin) and myoglobin. In CCSK, tumor cells were negative for cytokeratin, except for occasional tubular structures, and vimentin was demonstrated in only one case. In Wilms' tumor, epithelial components were positive for cytokeratin and stromal cells were positive for vimentin, while no staining was found in blastemal cells for either. Both desmin and myoglobin were negative in all tumor cells except for skeletal muscle cells in Wilms' tumor. In the current study, some neoplastic cells in CCSK were revealed to be of mesenchymal nature, but blastemal cells in Wilms' tumor were not.     

Clear cell sarcoma of the kidney. An immunohistochemical study

Three cases of clear cell sarcoma of the kidney (CCSK) and 5 cases of Wilms' tumor were investigated immunohistochemically to examine the expression of tissue-specific intermediate filaments (cytokeratin, vimentin, and desmin) and myoglobin. In CCSK, tumor cells were negative for cytokeratin, except for occasional tubular structures, and vimentin was demonstrated in only one case. In Wilms' tumor, epithelial components were positive for cytokeratin and stromal cells were positive for vimentin, while no staining was found in blastemal cells for either. Both desmin and myoglobin were negative in all tumor cells except for skeletal muscle cells in Wilms' tumor. In the current study, some neoplastic cells in CCSK were revealed to be of mesenchymal nature, but blastemal cells in Wilms' tumor were not.