Novel Ultrastructural Insights into the Clear-Cell Carcinoma of the Pancreas: A Case Report.

Pancreatic cancer, most frequently as ductal adenocarcinoma (PDAC), is the third leading cause of cancer death. Clear-cell primary adenocarcinoma of the pancreas (CCCP) is a rare, aggressive, still poorly characterized subtype of PDAC. We report here a case of a 65-year-old male presenting with pancreatic neoplasia. A histochemical examination of the tumor showed large cells with clear and abundant intracytoplasmic vacuoles. The clear-cell foamy appearance was not related to the hyperproduction of mucins. Ultrastructural characterization with transmission electron microscopy revealed the massive presence of mitochondria in the clear-cell cytoplasm. The mitochondria showed disordered cristae and various degrees of loss of structural integrity. Immunohistochemistry staining for NADH dehydrogenase [ubiquinone] 1 alpha subcomplex, 4-like 2 (NDUFA4L2) proved specifically negative for the clear-cell tumor. Our ultrastructural and molecular data indicate that the clear-cell nature in CCCP is linked to the accumulation of disrupted mitochondria. We propose that this may impact on the origin and progression of this PDAC subtype.

Age-Related Renal Microvascular Changes: Evaluation by Three-Dimensional Digital Imaging of the Human Renal Microcirculation Using Virtual Microscopy.

The renal microvasculature is targeted during aging, sometimes producing chronic kidney disease (CKD). Overdiagnosis of CKD in older persons is concerning. To prevent it, a new concept of "healthy aging" is arising from a healthy renal donor study. We investigated the renal microcirculatory changes of three older persons and compared them with that of one patient with nephrosclerosis using a three-dimensional (3D) reconstruction technique that we previously developed. This method uses a virtual slide system and paraffin-embedded serial sections of surgical material that was double-immunostained by anti-CD34 and anti-α smooth muscle actin (SMA) antibodies for detecting endothelial cells and medial smooth muscle cells, respectively. In all cases, the 3D images proved that arteriosclerotic changes in large proximal interlobular arteries did not directly induce distal arterial change or glomerulosclerosis. The nephrosclerotic patient showed severe hyalinosis with luminal narrowing of small arteries directly inducing glomerulosclerosis. We also visualized an atubular glomerulus and intraglomerular dilatation of an afferent arteriole during healthy aging on the 3D image and showed that microcirculatory changes were responsible for them. Thus, we successfully visualized healthy aged kidneys on 3D images and confirmed the underlying pathology. This method has the ability to investigate renal microcirculatory damage during healthy aging.

Sinonasal clear cell adenocarcinoma: a case report.

BACKGROUND: Nonsalivary adenocarcinomas are the most interesting tumors found in the sinonasal area. They are rare tumors arising from surface epithelium. The clear cell type of this tumor is even more rare. We present cytologic findings of clear cell sinonasal adenocarcinoma and related pitfalls. CASE: A 52-year-old woman presented with a left-cheek facial mass of 3-4 years' duration, with progressive enlargement, nasal discharge and discoloration of the lateral side of her left eye. Computed tomography was performed, revealing an expansile mass involving the nasal cavity, left maxillary sinus, ethmoid sinus with extension to sphenoid sinus, left side of oral cavity and left orbit. Fine needle aspiration performed through the upper buccogingival canine fossa showed clusters of epithelial cells with clear cytoplasm, round nuclei, inconspicuous nucleoli and slight pleomorphism. Some normal ciliated columnar epithelial cells are identified in the vicinity of neoplastic cells. The mass was reported to be a clear cell neoplasm, and excision of the whole mass was performed. CONCLUSION: Cytologic findings of this rare tumor overlap with those of salivary gland-type tumors with clear cell change and should be added to the list of head and neck tumors with clear cell change.

Non-muscle-invasive clear cell carcinoma of the urinary bladder: Is cystectomy necessary?

We report the clinical presentation, histological findings and management of a 49-year-old female patient with non-muscle-invasive clear cell carcinoma of the urinary bladder. In the literature, there are only seven such case reports. We feel that transurethral resection of the bladder tumour followed by close cystoscopy surveillance is a suitable management for non-muscle-invasive clear cell carcinoma of the urinary bladder.

Sonographic morphology scores (SMS) for differentiation between benign and malignant adnexal masses.

OBJECTIVE: To determine the sensitivity and specificity of a scoring system for distinguishing between benign and malignant adnexal masses and to detect threshold scores for prediction of malignant ovarian tumors. STUDY DESIGN: Cross-sectional diagnostic testing. SETTING: Department of Obstetrics and Gynecology, Faculty of Medicine, Chiang Mai University. SUBJECTS: A total 158 patients scheduled for elective surgery due to ovarian tumors at Maharaj Nakorn Chiang Mai Hospital between June 16, 2002 and August 8, 2004 were recruited into the study. METHODS: All patients were sonographically examed within 72 hours before surgery by the same sonographer to evaluate the morphology including wall structure, shadowing, septum, echogenicity and score the tumors. The final diagnosis was based on either pathological or operative findings. MAIN OUTCOME MEASURE: Sensitivity and specificity of the best cut-off score. RESULTS: A score of 5 from the receiver operating characteristic curve was found to be the best cut-off score, giving a sensitivity and a specificity of 85% and 70%, respectively. CONCLUSION: Sonographic morphology scores are useful in distinguishing adnexal malignancies from benign lesions in some selected cases.

Clear cell "sugar" tumor of the pancreas. A novel member of the family of lesions characterized by the presence of perivascular epithelioid cells.

We report at unique, previously unreported pancreatic tumor occurring in a 60-year-old woman who was preoperative diagnosed on cytoaspiration as having clear cell carcinoma. The resected tumor consisted of a population of large epithelioid cells with clear or eosinophilic, granular cytoplasm, rich in glycogen, with nuclear pleomorphism and no mitotic activity. In spite of the epithelioid appearance, the tumor cells were negative for epithelial (CAM 5.2, KL1, AE1-AE3), endocrine (neuron-specific enolase [NSE], chromogranin A), and acinar (lipase, amylase) markers and positive for actin and melanogenesis-related marker HMB 45. Ultrastructurally, the neoplastic cells showed membrane-bound granules; no evidence of either epithelial or melanocytic differentiation was present. These morphophenotypic features have never been reported in a pancreatic tumor and overlap those of clear cell "sugar" tumor of the lung. The same morphophenotypic features are observed in a family of lesions characterized by the presence of the perivascular epithelioid cell that also includes lymphangiomyomatosis and angiomyolipoma. The present case may be considered a novel member of this family of lesions. We propose this new entity be named clear cell "sugar" tumor of the pancreas.

Clear cell myomelanocytic tumor of the falciform ligament/ligamentum teres: a novel member of the perivascular epithelioid clear cell family of tumors with a predilection for children and young adults.

The perivascular epithelioid cell family of tumors (PEComas), defined by their co-expression of melanocytic and muscle markers, includes angiomyolipoma, lymphangioleiomyoma, and clear cell "sugar" tumors of the lung, pancreas, and uterus. We present seven cases of a unique and previously unrecognized tumor of children and young adults, which represents a new addition to the PEComa group of tumors. Culled from three institutions over a 50-year period, all cases occurred in or immediately adjacent to the ligamentum teres and falciform ligament. Six patients were female and one male; their ages ranged from 3 to 21 years (median, 11 yrs). Tumor sizes ranged from 5 to 20 cm (median, 8 cm). All cases consisted of clear to faintly eosinophilic spindled cells arranged in fascicular and nested patterns. The cells had small but distinct nucleoli and low mitotic activity. Immunohistochemically, all cases were positive with antibodies to gp100 protein (HMB-45) and negative for S-100 protein. In three of the seven cases studied immunohistochemically, the tumors expressed smooth muscle actin, melan-A, microphthalmia transcription factor (MiTF), and myosin, but not desmin. No expression of the TSC2 gene product, tuberin, was seen in three cases. One case studied cytogenetically disclosed a t(3;10). Follow-up data, available in six of seven cases (median duration, 18 mos), showed five patients to be free of disease and one to have a radiographically presumed lung metastasis. We think these tumors comprise a new entity for which we propose the term "clear cell myomelanocytic tumor of the falciform ligament/ligamentum teres." The differential diagnosis of these tumors includes clear cell sarcoma of tendons and aponeuroses, leiomyosarcoma, and angiomyolipoma.

Ultrastructural observations on mitochondria and microvesicles in renal oncocytoma, chromophobe renal cell carcinoma, and eosinophilic variant of conventional (clear cell) renal cell carcinoma.

On light microscopic examination, the morphologically overlapping features of granular eosinophilic cytoplasm in renal oncocytoma and the eosinophilic variants of chromophobe renal cell carcinoma and conventional (clear cell) renal cell carcinoma may pose difficulties in diagnosis. We investigated the ultrastructure of 5 renal oncocytomas, 7 eosinophilic variants of chromophobe renal cell carcinoma, and 5 eosinophilic variants of conventional (clear cell) renal cell carcinoma. Special attention was paid to mitochondria and microvesicles and interrelations thereof. The electron microscopic features were correlated with the light microscopic findings. All of the tumors had abundant mitochondria. Although abundant microvesicles were present in all of the chromophobe renal cell carcinomas, scant numbers of microvesicles were also sometimes present in renal oncocytomas (2 of 5) and in the eosinophilic variant of conventional (clear cell) renal cell carcinoma (1 of 5). The mitochondria in all three types of renal neoplasms studied differed in morphology, being predominantly uniform and round with predominantly lamellar cristae in renal oncocytoma, variable in shape and size with predominantly tubulocystic cristae in chromophobe renal cell carcinoma, and swollen and pleomorphic with rarefied matrix and attenuated cristae in the eosinophilic variant of conventional (clear cell) renal cell carcinoma. Variable numbers of mitochondria in all of the chromophobe renal cell carcinomas had outpouchings of the outer membranes, some of which carried parts of inner membrane within them. These outpouchings closely resembled the nearby cytoplasmic microvesicles, as did the tubulocystic cristae of the mitochondria. Some microvesicles contained homogeneous, electron-dense, finely granular matrix, similar to that seen in mitochondria. In one of seven chromophobe renal cell carcinomas, microvesicles were present in rough endoplasmic reticulum, and in two others, mitochondria were present within some vesicles. These features strongly suggest a close relationship between the microvesicles and mitochondria. Based on the role of vesicle formation in normal mitochondriogenesis, and some of our observations, we propose that defective mitochondriogenesis may be the source of microvesicles in chromophobe renal cell carcinomas.

Clear cell carcinoma of the lung: a case report and review of the literature.

Clear cell carcinoma of the lung is an extremely rare type of lung cancer with doubtful etiology. This present case showed that the tumor cells contained abundant cytoplasmic glycogen with a diffusely distributed pattern and intracellular glandular structure electron microscopically. Immunohistochemical study revealed that the tumor cells expressed not only epithelial marker including cytokeratin and epithelial membrane antigen, but also Ley, one of stage-specific embryonic carbohydrate antigens. The diagnosis of pulmonary clear cell carcinoma should be done carefully, because benign clear cell tumor and secondary renal cell carcinoma show similarities in a histologic appearance but not in their management and prognosis.

Prognostic value of proliferative activity of ovarian carcinoma as revealed by PCNA and AgNOR analyses.

Proliferative activity of a malignant tumor is known to reflect its biologic aggressiveness. Proliferating cell nuclear antigen (PCNA) is a marker of cellular proliferation, and silver-stained nucleolar organizer regions (AgNORs) have been shown to correlate with ploidy and proliferative activity of cells depending on the method of assessment; the mean number of AgNORs per nucleus reflects ploidy, whereas the mean percentage of nuclei with five or more AgNORs per nucleus indicates proliferative activity. In ovarian carcinoma, the prognostic value of these markers has not been well defined. We studied PCNA expression and the AgNOR count in 43 ovarian carcinomas (25 serous, 13 mucinous, and 5 clear cell types) to assess their potential prognostic significance compared with the stage of disease and histopathologic features of the tumors. Eight benign (four serous and four mucinous) and six normal ovarian tissues were also evaluated. A standard colloidal silver staining and an immunohistochemical method were used. The mean percentage of PCNA positivity (PCNA index), the mean number of AgNORs per nucleus (mAgNOR), and the mean percentage of nuclei with more than five AgNORs per nucleus (pAgNOR) for each lesion were determined. In univariable analysis, PCNA indexes and mAgNOR and pAgNOR values were significantly higher in benign ovarian tumors compared with normal ovarian tissues and in adenocarcinomas compared with benign ovarian tumors. In multivariable analysis, PCNA indexes were significantly associated with histologic grade (P=.003), whereas associations of mAgNOR and pAgNOR values were highly significant with both histologic grade and disease stage (P=.0001). Histologic grade, but not subtype, was also associated with disease stage at a significant level (P=.008). Our findings indicate that differences in biologic behavior of ovarian carcinomas may, in part, be defined by differences in their ploidy and proliferative activity, and that whereas PCNA expression is of limited value, assessment of AgNORs holds promise in providing valuable prognostic information on the biologic behavior of the tumors.

Concomitant loss of mitochondria and the DNA repair protein hOGG1 in clear cell carcinoma of the kidney.

The kidney is subjected to DNA oxidative damage from reactive oxygen species generated by free radicals and toxic metabolites, leading to formation of DNA base lesions. One such DNA lesion is 8-oxoguanine, which, if not sufficiently removed, is potentially mutagenic because it can cause G:C to T:A transversion in subsequent DNA replication. The human 8-oxoguanine DNA glycosylase 1 (hOGG1) gene on chromosome 3, a region (3p25-26) that shows frequent loss of heterozygosity in clear cell renal cell carcinoma (CC-RCC), encodes for a DNA repair enzyme capable of excision repair of 8-oxoguanine. Of the known isoforms of the hOGG1 enzyme (types Ia, Ib, Ic, Id, and II), only 1, Ia, is found in the nucleus, whereas the rest show a mitochondrial distribution. We investigated, by an immunohistochemical staining method, the expression of hOGG1 protein in 40 cases of CC-RCC, using archival formalin-fixed tissue. To localize the hOGG1 enzyme in normal and tumor tissue, immuno-staining against cytochrome c, a specific mitochondrial enzyme, was also performed. The results showed marked reduction in hOGG1 expression in the majority of tumors, with complete loss of staining seen in 26 (65%) and moderate and weak positive staining present in 9 (22.5%) and 5 (12.5%) of the cases, respectively. Strong hOGG1 protein expression was present in normal tubular epithelium, located in the mitochondria. The results correlated with the expression patterns of cytochrome c. The findings indicate that loss of hOGG1 expression may have a role in development or progression of CC-RCC.

Establishment and characterization of cell lines derived from serous adenocarcinoma (JHOS-2) and clear cell adenocarcinoma (JHOC-5, JHOC-6) of human ovary.

The cell lines designated JHOS-2, JHOC-5 and JHOC-6 were established from epithelial ovarian carcinomas. JHOS-2 was established from a serous adenocarcinoma of a 45-year-old Japanese woman, JHOC-5 from a recurrent tumor of a clear cell adenocarcinoma of a 47-year-old Japanese woman and JHOC-6 from a tumor of a clear cell adenocarcinoma of a 43-year-old Japanese woman. These cell lines have grown well and serial passages were successively carried out more than 20 times. The monolayer cultured cells revealed neoplastic and pleomorphic features, and grew in multilayers. Electron micrographs revealed epithelial origins that had desmosomes and tonofilaments.

Establishment of two human renal cell carcinoma cell lines with different chemosensitivity.

Two cell lines, SKR1 and NKK1, were established from renal cell carcinomas (RCC) with different histopathologic characteristics: SKR1 from grade 3, solid type, pleomorphic cell type carcinoma in a 66-year-old male and NKK1 from grade 2, alveolar type, clear cell carcinoma in a 49-year-old female. Electron microscopic study showed the presence of microvilli on cell surface and desmosome-like structures between cells in both lines. Doubling time and plating efficiency of SKR1 were 28 h and 37%, respectively, whereas those of NKK1 were 45 h and 22%, respectively. The chromosome number of both cell lines was 100% aneuploid with a mode of 74 chromosomes for SKR1 and 84 for NKK1. Both SKR1 and NKK1 induced tumors at the site of subcutaneous injection of nude mice. The morphologic characteristics of the tumor were similar to those of each original tumor. NKK1 was about 20 times more resistant to doxorubicin and vinblastine as compared to SKR1. Expression of P-glycoprotein was considered to be one of the factors responsible for such multidrug resistant phenotype of NKK1 cells. These two lines with different chemosensitivity may be a useful model for developing new therapeutic strategies for RCC.

Histogenesis of hollow cell ball structure of ovarian and endometrial adenocarcinoma cells in vivo and in vitro.

Hollow cell ball structure is often found in the ascites of adenocarcinoma patients. How to form a hollow cell ball structure was studied in vivo and in vitro, using the human cell lines derived from ovarian and endometrial adenocarcinomas. The hollow cell ball structure was formed by horizontal rotation culture of 1 x 10(7) single-suspended cells for 24 hours or by transplanting 1 x 10(6) single-suspended cells into the peritoneal cavity of nude mouse for 24 hours. At one month after transplantation hemi-cyst and hollow cell ball structure were formed in the outermost layer of the grafted tumor on the intraperitoneal serous membrane in the nude mouse. And also great number of floating hollow cell ball structure in the ascites were observed. These results suggest that mechanisms of formation of hollow cell ball structure found in the ascites; one by cell aggregate of single cells, sometimes inner cells of cell aggregate fall into necrosis or secretes mucus inside and make a hollow cell ball structure and another by the removed as the hollow cell ball structure grown from hemi-cyst on the surface of intraperitoneal grafted tumor.

Extensively cystic renal neoplasms: cystic nephroma, cystic partially differentiated nephroblastoma, multilocular cystic renal cell carcinoma, and cystic hamartoma of renal pelvis.

Predominantly cystic renal neoplasms have been the source of diagnostic confusion and controversy. In this review, the authors analyze the clinical and pathological features of four entities that consistently exhibit a diffusely cystic growth pattern, are strikingly similar in their gross appearances, and are not separable by preoperative imaging studies. Based on the literature, this review concludes that tumors in young children that have been classified as cystic nephroma and cystic partially differentiated nephroblastoma likely represent a single entity, and all should be considered highly cystic Wilms' tumors with little or no capacity for invasion or metastasis and diagnosed as cystic partially differentiated nephroblastoma. Conversely, cystic nephroma in adults has no discernible connection with Wilms' tumor or nephrogenic rests and should be considered a benign composite neoplasm of stroma and epithelium of unknown histogenesis, which may rarely become malignant with secondary development of a sarcoma. Multilocular cystic renal cell carcinoma appears to be unrelated to cystic nephroma and if the following criteria are met, it appears to be a neoplasm with an intrinsically cystic growth pattern, and no, or at most little, malignant potential: (1) an expansile mass is surrounded by a fibrous wall, (2) the interior of the tumor entirely is composed of cysts and septa with no expansile solid nodules, and (3) the septa contain aggregates of epithelial cells with clear cytoplasm. Cystic hamartoma of the renal pelvis is a rare, complex tumor composed of stroma with a prominent smooth muscle component and a variety of epithelial elements.

Clear cell neoplasms of the endocrine system and thymus.

Clear cell tumors of the endocrine system and thymus are rare lesions with which surgical pathologists have only infrequent contact. As a result, these neoplasms may be misinterpreted and incorrectly classified. This review considers the histological, immunohistochemical, and ultrastructural features of clear cell pituitary adenomas, parathyroid tumors, pancreatic endocrine neoplasms, adrenocortical proliferations, and thymic malignancies. Emphasis is placed throughout on differential diagnosis with microscopically-similar lesions. Clear cell endocrine tumors and thymic lesions manifest a variety of potential lineages, including examples with epithelial, neural, germ cell, and lymphoid differentiation. Because of the wide differences in behavior and recommended treatment in this group, accuracy in diagnosis is essential.

Glycogen-rich clear cell carcinoma of the breast: report of a case with fine-needle aspiration cytology and immunocytochemical and ultrastructural studies.

Fine-needle aspiration cytology, immunocytochemistry, and electron microscopic findings are described in a case of glycogen-rich clear cell carcinoma of the breast. The aspirate contained many small and large papillary cell groups and numerous single tall columnar cells with apical cytoplasmic projections and mild to moderate degree of nuclear pleomorphism. Cytochemical localisation of glycogen and immunostaining on air-dried smears with CEA and actin monoclonal antibodies permitted the correct identification and differential diagnosis of the tumor. Electron microscopic examination of the resected specimen confirmed the diagnosis of glycogen-rich clear cell carcinoma. The differential diagnosis and potential diagnostic pitfalls are discussed, and recommendation are offered to prevent misdiagnosis.

Excessive formation of basement membrane substance in clear-cell carcinoma of the ovary: diagnostic value of the "raspberry body" in ascites cytology.

Formation of basement membrane-like substance or so-called collagen core was characteristic of clear-cell carcinoma of the ovary in ascites cytology. The hyaline extracellular material was stained light green in Papanicolaou smears and pinkish to purplish red in Giemsa preparations and was frequently observed within the cancer cell clusters in all ten samples of clear-cell carcinoma. Such a structure termed "raspberry body" was focally seen in one of 30 specimens of serous cystadenocarcinoma and one of 30 samples containing reactive mesothelial cells. The "raspberry body" was not found in ascitic fluid from ten patients with mucinous cystadenocarcinoma and two with endometrioid carcinoma. Overproduction of the acidic-charged basement membrane substance was confirmed by 1) cytochemical positivity for periodic acid-Schiff, alcian blue (pH 2.5 or pH 1.0), colloidal iron, and periodic acid-methenamine silver, 2) immunocytochemical demonstration of laminin and type 4 collagen, and 3) ultrastructural identification of excessive formation of the basal lamina. Recognition of the "raspberry body" helps cytopathologists make a cytologic diagnosis of this chemotherapy-resistant malignancy disseminated in ascitic fluid.

Distribution of subtypes of metastatic renal-cell carcinoma: correlating findings of fine-needle aspiration biopsy and surgical pathology.

Clear-cell (CRCC), papillary (PRCC), and chromophobe (CHRCC) renal-cell carcinoma (RCC) are the three most frequent subtypes of RCC. The rate and distribution of their metastatic lesions have not been well studied in cytopathological materials. Sixty-two fine-needle aspiration biopsy cases of metastatic RCC were studied and correlated with surgical pathology of RCCs with and without metastasis. Special stains for glycogen and immunostaining for cytokeratins, vimentin epithelial membrane antigen (EMA), and carcinoembryonic antigens, and electron microscopic studies were performed. Fifty-nine cases of CRCC and three of PRCC subtypes were retrieved from the cytopathology files at the Ottawa Hospital in a period of 10 years. Of these cases, 10 metastatic CRCC and one metastatic PRCC were diagnosed prior to the diagnosis of the primary tumor. CHRCC and sarcomatoid RCC were not represented in cytopathological specimens. CRCC displayed characteristic filmy cytoplasm and nuclei with prominent nucleoli. PRCC was characterized by dense cytoplasm, large nuclei with prominent nucleoli, and papillary architectures. In addition, all RCCs were characterized by the presence of glycogen and the absence of mucin by using histochemical techniques and electron microscopic studies and positive reactivity for cytokeratins (CK) and vimentin (VIM). In the same period, there were a total of 380 patients with RCC divided into 310 CRCCs, 55 PRCCs, and 15 CHRCCs associated with metastases in 142, 9, and 1 case, respectively. CRCC is by far the most common subtype found in metastases sampled in cytopathology. PRCC, CHRCC, and sarcomatoid RCC were underrepresented. Awareness of this propensity of RCC and the characteristic cytopathological, histochemical, immunohistochemical, and ultrastructural features are helpful in the diagnosis of metastatic RCC.

Clear cell carcinoma arising in a cesarean section scar. Report of a case with fine needle aspiration cytology.

BACKGROUND: Clear cell carcinoma arising in a cesarean section scar is an extremely rare disease. To the best of our knowledge, there is no published report on the aspiration cytology. CASE: A 56-year-old woman presented with a mass in a cesarean section scar. Initially an abdominal desmoid was considered, but the features of fine needle aspiration (FNA) cytology suggested an adenocarcinoma. The resected tumor was histologically composed of clear cell carcinoma showing cystic, solid and papillary patterns. CONCLUSION: FNA cytology of masses arising in a surgical scar can be a useful tool in obtaining an accurate pathologic diagnosis of a malignant neoplasm.