Altered mucin core peptide expression in acute and chronic cholecystitis.

Human mucin genes include membrane-bound mucins (MUC1, MUC3, MUC4) and secretory mucins (MUC2, MUC5AC, MUC5B, MUC6). Our aim was to determine mucin gene expression in human gallbladder cell lines, normal gallbladder from liver donors (N = 7) and surgical specimens with mild chronic cholecystitis (N = 29), chronic cholecystitis (N = 48), and acute and chronic cholecystitis (N = 27). MUC1 mRNA was ubiquitous; however, only rare MUC1 immunoreactivity was detected. MUC3, MUC5AC, MUC5B, and MUC6 mRNA were present in all gallbladder specimens and cell lines examined. Prominent MUC3, MUC5AC, MUC5B, and MUC6 immunoreactivity was present in 86-100% of normal gallbladders. The frequency of MUC5AC reactivity was decreased in specimens with acute cholecystitis (P < 0.05). In contrast, MUC2-reactivity was absent in normal gallbladder and present in 53.8% of acute cholecystitis specimens (P < 0.05). Surface epithelium is characterized by MUC3, MUC5AC, and MUC5B, whereas deeper mucosal folds display MUC5B and MUC6 immunoreactivity. Gallbladder epithelium demonstrates a unique and diverse pattern of mucin core proteins that becomes altered with increasing degrees of inflammation.

Correlation of CD44S expression in renal clear cell carcinomas with subsequent tumor progression or recurrence.

BACKGROUND: Recent reports have shown altered expression of CD44 in renal cell carcinomas. However, to the authors' knowledge there are no data correlating CD44 expression in renal cell carcinomas with subsequent tumor progression or recurrence, nor is there information about the presence of particular splice variants of CD44 in these tumors. METHODS: The authors examined the immunohistochemical expression of CD44S, the standard isoform of CD44, in renal cell carcinomas from 43 patients using 2 different monoclonal antibodies, Mab2137 and Hermes-3. In addition, they stained the renal cell carcinomas with antibodies to 2 splice variants of CD44, CD44v3 and CD44v6. RESULTS: Increased staining of renal clear cell carcinomas with Mab2137 was observed in high grade versus low grade tumors (45% vs. 0%, P = 0.013), whereas increased staining of clear cell carcinomas with Hermes-3 was noted in high stage versus low stage tumors (40% vs. 0%, P = 0.006). Few tumors stained with antibodies to CD44v3. Although increased expression of the splice variant CD44v6 was noted in papillary versus clear cell carcinomas, and increased staining of papillary carcinomas with Mab2137 and with antibodies to CD44v6 was noted for low stage versus high stage tumors, these differences did not achieve statistical significance. Clinical follow-up of at least 43 months was available for 26 patients. Six of these patients (five with clear cell carcinoma and one with papillary carcinoma) developed progressive or recurrent disease. The primary tumors from all 5 patients with progressive or recurrent clear cell carcinoma showed staining with Mab2137, whereas the primary tumors from only 2 of the 15 patients with at least 43 months follow-up and no evidence of progressive or recurrent clear cell carcinoma (13%) showed staining with Mab2137 (P = 0.001). Alternatively, 5 of 7 clear cell carcinomas (71%) that stained with Mab2137 were from patients who subsequently developed recurrence or progression, compared with 0 of 13 clear cell carcinomas that did not stain. Similar findings were not observed for papillary carcinomas, which appeared to be biologically distinct from clear cell carcinomas. CONCLUSIONS: CD44S staining with Mab2137 correlates with progression or recurrence of clear cell renal cell carcinoma. CD44S may, therefore, play a pathogenetic role in tumor progression.

Subcellular immunolocalization of protein kinase CK2 in normal and carcinoma cells.

CK2 is a messenger-independent protein serine/threonine kinase that has been implicated in cell growth and proliferation. Our recent analysis of squamous cell carcinomas of the head and neck (SCCHN) revealed a significant elevation in CK2 activity in these tumor cells relative to normal mucosa of the upper aerodigestive tract and suggested a correlation with aggressive tumor behavior and poor clinical outcome. In order to further define the distribution of CK2 in these tissues, we have examined the immunohistochemical staining pattern of surgical specimens of both SCCHN tumors and normal upper aerodigestive tract mucosa using a monoclonal antibody directed against the catalytic subunit CK2-alpha of the kinase, and have compared these data with the subcellular distribution of CK2 activity in these same tissues. These measurements showed that CK2 is predominantly localized to the nuclei of the tumor cells, which agreed closely with the immunohistochemical staining pattern of CK2-alpha in tumor cells. The chiefly nuclear distribution of CK2-alpha immunostaining found consistently in SCCHN tumor cells and tumor-infiltrating lymphocytes contrasted with a relatively more predominant cytosolic staining pattern exhibited by various cellular constituents of normal oropharyngeal mucosa. The immunostaining pattern of CK2-alpha revealed that staining was observed in the cells stained for the proliferation-marker Ki-67; however, strong distinct immunostaining for CK2-alpha was also observed in large numbers of other cells in these same tumors, suggesting that CK2 elevation in these tumors is not a reflection of proliferative activity alone, but may also relate to the pathobiological behavior of the tumor.

Small-cell carcinoma of the lung manifesting as acute hepatic failure.

In this report, we describe four cases of small-cell carcinoma of the lung manifesting as acute hepatic failure. These cases were noteworthy for the presence of hepatomegaly and substantially increased serum lactate dehydrogenase and uric acid levels. The ratio of normalized serum lactate dehydrogenase to normalized serum alanine aminotransferase from the 4 cases reported herein (mean +/- SE, 3.63 +/- 1.10) was significantly greater than the ratio obtained from the 12 cases of nonmalignant fulminant hepatic failure (mean +/- SE, 0.46 +/- 0.18; P < 0.001). Chest radiographs and abdominal imaging studies showed no neoplastic process in three of the four cases. Postmortem examinations disclosed extensive infiltration of the liver by metastatic small-cell carcinoma of the lung. A review of the literature revealed 13 additional similar cases. We conclude that metastatic small-cell carcinoma of the lung should be considered in cases of acute hepatic failure associated with hepatomegaly, substantially increased lactate dehydrogenase levels in comparison with alanine aminotransferase values, and increased uric acid levels even if imaging studies show no lesion. A liver biopsy done early during the hospital course is appropriate for diagnosis and for prevention of inappropriate transfer of the patient to a liver transplant center.

B-cell gene rearrangement in benign and malignant lymphoid proliferations of mucosa-associated lymphoid tissue and lymph nodes.

The polymerase chain reaction (PCR) with polyacrylamide gel electrophoresis was used to study patterns of immunoglobulin heavy chain (IgH) gene rearrangement (GR) in formalin-fixed, paraffin-embedded specimens of lymphomas and reactive conditions of mucosa-associated lymphoid tissue (MALT) and lymph node. DNA amplification was performed directly on sections obtained from paraffin blocks. Five patterns of PCR products were observed: a single band, two or more discrete bands, smearing, a single band overlying a smear, and two or more bands over a smear. A pure polyclonal pattern (smear) was observed in all of the reactive lymph nodes but in only 15% of cases of Helicobacter pylori (HP) gastritis with lymphoid hyperplasia, 25% of cases of HP gastritis without lymphoid hyperplasia, and 37% of colonic specimens of various types. Patterns consisting of multiple bands with or without background smearing were common in gastritis, colitis, and gastric lymphomas. Single bands or dominant bands were present in all lymph node and salivary gland lymphomas, 12 of 14 cases of gastric lymphoma, and 17 of 20 cases of HP gastritis with lymphoid hyperplasia. These bands were reproducible in deeper sections from the same paraffin block or similar areas sampled in different blocks in all of the lymph node and salivary gland lymphomas, 11 of 12 gastric lymphomas, but only 1 of 17 cases of HP gastritis with lymphoid hyperplasia. Bands were also found in 3 of 20 cases of HP gastritis without lymphoid hyperplasia and 17 of 38 colonic specimens, but these were not reproducible. The complexity of patterns of IgH GR in acquired MALT compared with lymph nodes may be the result of a relative paucity of B-cell clones or preferential proliferation of B-cell clones with a limited area of distribution.

Human carcinomas variably express the complement inhibitory proteins CD46 (membrane cofactor protein), CD55 (decay-accelerating factor), and CD59 (protectin).

Normal human tissues express membrane-associated complement inhibitory proteins that protect these tissues from damage by autologous complement. To determine whether neoplasms also express these proteins, we examined the distribution of the complement inhibitors decay-accelerating factor (DAF), CD59 (protectin), and membrane cofactor protein in frozen samples of human breast, colon, kidney, and lung carcinomas and in adjacent non-neoplastic tissues, using immunohistochemistry. All samples were also studied for deposition of C3 fragments and activated C5b-9. Differences between normal tissues and the corresponding neoplasms were often observed, with loss or gain of expression of one or more inhibitors. Ductal carcinomas of the breast showed the most variation in phenotype; some tumors expressed only one inhibitor while others expressed different combinations of two or three inhibitors. Colon carcinomas, by contrast, stained intensely for all inhibitors. Renal cell carcinomas had weak to moderate expression of one to three inhibitors, generally DAF and CD59, whereas non-small cell carcinomas of the lung usually expressed CD59 and membrane cofactor protein with variable DAF immunoreactivity. The two small cell carcinomas of the lung showed little or no staining for any inhibitor. Activated C5b-9 deposition was seen adjacent to tumor nests in a minority of carcinomas and showed no correlation with complement inhibitor expression. C3 fragment deposition was minimal. Our results demonstrate that most carcinomas, with the exception of small cell carcinomas of the lung, do express one or more complement inhibitors at a level likely to inhibit complement-mediated cellular damage. Unexpectedly, large quantities of DAF and CD59 were often observed in tumor stroma, with only limited deposition in normal connective tissue. This suggests that carcinomas may supplement the activity of membrane-associated complement inhibitors by release of soluble forms of DAF and CD59 into the surrounding extracellular matrix.

Membrane-bound (MUC1) and secretory (MUC2, MUC3, and MUC4) mucin gene expression in human lung cancer.

Abnormalities of mucin-type glycoproteins have been described in lung cancers, but their molecular basis is unknown. In this study, mucin-core-peptide-specific antibodies and cDNA probes were used to determine the relative expression of mucin genes corresponding to one membrane-bound mucin (MUC1), two intestinal mucins (MUC2 and MUC3), and one tracheobronchial mucin (MUC4) in normal (nonneoplastic) lung, and in lung neoplasms. Normal lung tissues exhibited a distinct pattern of mucin gene expression, with high levels of MUC1 and MUC4 mRNA and low to absent levels of MUC2 and MUC3 mucin immunoreactivity and mRNA. In contrast, lung adenocarcinomas, especially well-differentiated cancers, exhibited increased MUC1, MUC3, and MUC4 mRNA levels. Lung squamous-cell, adenosquamous, and large-cell carcinomas were characterized by increased levels of MUC4 mucin only. We conclude that the expression of one membrane-bound and several secretory-type mucins is independently regulated and markedly altered in lung neoplasms. The frequent occurrence of increased MUC4 transcripts in a variety of non-small-cell lung cancers indicates the potential importance of this type of mucin in lung cancer biology.

Mucin gene expression in normal, preneoplastic, and neoplastic human gastric epithelium.

Mucins synthesized by malignant cells may contribute (via decreased cellular adhesion and immune recognition) to cancer invasion and metastases. Human mucins are derived from a heterogeneous family of genes, labeled MUC1-6. Our aim was to determine the pattern of mucin gene expression in normal, preneoplastic (intestinal metaplasia), and malignant gastric specimens. Probes and antibodies for specific mucin tandem repeat sequences were used for RNA and immunohistochemical analysis. Normal stomach mucosa was characterized by expression of MUC1, MUC5, and MUC6 mRNA and immunoreactive protein, without MUC2, MUC3, and MUC4 gene expression. In contrast, high levels of MUC2 and MUC3 mucin mRNA and immunoreactive protein were found in specimens with intestinal metaplasia. Gastric cancers exhibited markedly altered secretory mucin mRNA levels compared with adjacent normal mucosa, with decreased levels of MUC5 and MUC6 mRNA and increased levels of MUC3 and MUC4 mRNA. Overall, immunoreactive MUC1 mucin was detected in 72% of 33 gastric cancers, and secretory mucin core peptides were expressed in 34% (MUC2), 45% (MUC3), 19% (MUC5), and 57% (MUC6) of these specimens. Coexpression of multiple (three or more) mucin core proteins occurred in 15 of 25 (60%) advanced (stages III and IV) cancers compared with 1 of 8 (12.5%) early (stages I and II) cancers (P < 0.048). We conclude that human gastric epithelium has a unique mucin gene pattern, which becomes markedly altered in preneoplastic and neoplastic specimens. Increased mucin gene heterogeneity in gastric adenocarcinomas is associated with advanced cancer stage.

A microwave method that enhances detection of aberrant p53 expression in formalin-fixed, paraffin-embedded tissues.

OBJECTIVE: Detection of aberrantly accumulated p53 protein by immunohistochemistry may have prognostic significance in many human neoplasms. We wished to identify a technique applicable to formalin-fixed, paraffin-embedded sections that would reliably yield results equivalent to frozen-section immunohistochemistry. DESIGN: We compared the frequency of p53 immunostaining obtained by applying monoclonal antibodies PAb1801, DO7, or DO1, a 1:1 PAb1801-DO7 cocktail, and a 1:1 PAb1801-DO1 cocktail to fresh-frozen and formalin-fixed, paraffin-embedded tissues from 36 lung and upper aerodigestive-tract carcinomas. With the formalin-fixed tissues, we compared pepsin predigestion with microwave irradiation in citrate buffer as means of enhancing the sensitivity of p53 detection. SETTING AND PATIENTS: All tissues were obtained from surgical resections of tumors, from patients who underwent surgery at the Minneapolis Department of Veterans Affairs Medical Center between 1990 and 1992. MAIN OUTCOME MEASURES: The sensitivity of different paraffin section techniques for immunohistochemical detection of accumulated p53 protein was determined in reference to the optimal frozen section method (defined as the method that yielded the greatest number of p53-positive cases in frozen tissue). RESULTS: Microwave antigen retrieval markedly enhanced staining with PAb1801 and DO7 in paraffin sections, as compared with pepsin predigestion and no pretreatment. This technique was 100% sensitive relative to the optimal frozen tissue method. In contrast, staining with DO1 alone was not enhanced by microwaving. CONCLUSIONS: Microwave pretreatment in conjunction with the use of either PAb1801 or DO7 is highly efficacious in the immunohistochemical detection of aberrant p53 expression in formalin-fixed, paraffin-embedded tissues.

The role of tumor necrosis factor-alpha in acute endotoxin-induced hepatotoxicity in ethanol-fed rats.

An in vivo model of ethanol ingestion in rats was used to examine tumor necrosis factor-alpha production after intravenous injection with lipopolysaccharide or saline solution. Four groups of 125-gm male Sprague-Dawley rats were given one of the following four diets: liquid ethanol diet (ethanol, 36% of calories), liquid control diet, chow ad libitum or control liquid diet pair-fed to match calories consumed by ethanol-fed rats. After 6 wk of diet, all rats were injected with 1 mg/kg lipopolysaccharide or 0.9% saline. AST concentrations in the ethanol-lipopolysaccharide group (388 +/- 54 U/ml) were significantly increased compared with those in control-saline, ethanol-saline and control-lipopolysaccharide groups (166 +/- 23, 166 +/- 18, 219 +/- 47; p < 0.01). Serum tumor necrosis factor-alpha concentrations for the ethanol-LPS group (3,990 +/- 624 pg/ml) were increased compared with those in control-saline (87 +/- 18), ethanol-saline (68 +/- 24) and control-LPS (695 +/- 165) groups (p < 0.001). A strong correlation was seen between serum tumor necrosis factor-alpha and AST concentrations (r = 0.91, p < 0.001). Treatment with lipopolysaccharide also increased transcriptional levels of tumor necrosis factor-alpha-specific mRNA from hepatic Kupffer cells isolated from rats fed the long-term ethanol diet by a factor of 3 compared with control rats. From these data, we conclude that long-term ethanol administration sensitized hepatic Kupffer cells to secrete high levels of tumor necrosis factor-alpha after lipopolysaccharide injection. Increased serum tumor necrosis factor-alpha concentrations correlated directly with increased levels of serum transaminase, which may have reflected hepatic injury.

Induction of cytochrome CYPIA1 and formation of toxic metabolites of benzo[a]pyrene by rat aorta: a possible role in atherogenesis.

Cigarette smoking is a leading risk factor for atherosclerosis. Endothelial injury may be the initial event in this process. The carcinogenic metabolites of the polycyclic aromatic hydrocarbons found in cigarette smoke tars could cause this injury. We tested this model by examining the effect of 3-methylcholanthrene administration on aortic polycyclic aromatic hydrocarbon metabolism. Immunoblotting with a monoclonal antibody (mAb 1-7-1) specific for cytochromes CYPIA1 and CYPIA2 showed that aortic microsomes from treated, but not from control, animals contained CYPIA1; the CYPIA1 was primarily in the endothelium. Aortic microsomes from induced animals metabolized benzo[a]pyrene (BaP) to the 7R,8S,9,10-tetrahydrotetrol-, 7,8-dihydrodiol-, 1,6 quinone-, 3,6 quinone-, 6,12 quinone-, 3-hydroxy-, and 9-hydroxy-BaP. mAb 1-7-1 inhibited the formation of the tetrahydrotetrol, the dihydrodiol-BaP, and the 3-hydroxy-BaP but did not inhibit the quinones or the 9-hydroxy-BaP. Arachidonic acid did not affect metabolism. These data suggest that the aortas of induced animals metabolize the BaP in cigarette smoke to carcinogenic and toxic products and that this metabolism may initiate vessel injury and lead to the accelerated atherosclerosis seen in cigarette smokers.

Heterogeneity of mucin gene expression in normal and neoplastic tissues.

To determine the relative expression of distinct mucin genes in normal and neoplastic tissue, antibodies and cDNA probes that recognize the core tandem repeat sequences of membrane-bound (MUC1) and secreted (MUC2 and MUC3) mucins were used for immunohistochemical and RNA Northern and slot-blot analysis. MUC1 mRNA was detected in all epithelial tissues tested. MUC1 core peptide, recognized by monoclonal antibodies 139H2 and DF3, was highly expressed on apical membranes of bronchus, breast, salivary gland, pancreas, prostate, and uterus, and was sparsely expressed in gastric surface cells, gallbladder, small intestine, and colonic epithelium. In contrast, MUC2 and MUC3 gene expression was primarily restricted to the intestinal tract. MUC2 mRNA was highly expressed in normal jejunum, ileum, and colon, compared with very low levels in normal bronchus and gallbladder. MUC3 mRNA was highly expressed in normal jejunum, ileum, colon, and gallbladder. Immunohistochemical studies using antibodies against synthetic MUC2 (anti-MRP) and MUC3 (anti-M3P) peptides indicate that MUC2- and MUC3-producing cells in the gastrointestinal tract are distinct. Goblet cells of the small intestine and colon reacted strongly with anti-MRP, whereas M3P reactivity was restricted to columnar cells of small intestinal villi, surface colonic epithelium, and gallbladder. Mucin protein epitopes and mRNA levels were frequently altered in adenocarcinomas compared to corresponding normal tissues. Alterations included increased expression, aberrant expression, and, less frequently, loss of expression. Increased MUC1 immunoreactivity was observed in most adenocarcinomas of the breast, lung, stomach, pancreas, prostate, and ovary. In addition, with the exception of prostate cancer, focal aberrant expression of MUC2 and MUC3 epitopes was frequently observed. Increased MUC1, MUC2, and MUC3 epitopes were present in colon adenocarcinomas of all histological subtypes, with the greatest increase of MUC2 epitopes observed in colloid (mucinous) colon cancers. MUC2 or MUC3 mRNA levels were increased in colloid colon cancer compared with normal colon, however in well- and moderately well-differentiated colon cancers MUC1, 2 and 3 mRNA levels were decreased. Compared with corresponding normal tissue, MUC1 mRNA levels were increased in breast cancer and well-differentiated lung cancers, and MUC3 mRNA was increased in gastric adenocarcinomas. Normal stomach lacked both MUC2 and MUC3 immunoreactivity and mRNA, however, MUC2 and MUC3 proteins and mRNA were highly expressed in gastric intestinal metaplasia. In conclusion, mucin genes are independently regulated and their expression is organ- and cell type-specific. Furthermore, neoplastic transformation is associated with dys-regulated expression of both membrane-bound and secreted mucin core protein epitopes and may be due to altered mucin mRNA levels and/or altered mucin glycosylation.

Tricholemmal carcinoma: clinicopathologic study of 10 cases.

Tricholemmal carcinoma (TLC) is a cutaneous adnexal tumor with presumed external hair sheath differentiation. In order to better understand the salient features of this neoplasm, we analyzed the histologic and clinical findings in 10 cases of TLC. Eight patients were males, and two were female; they ranged in age from 55-88 years. Each tumor occurred in hair bearing, sun-exposed skin, and involved the scalp, face, trunk, or upper extremities. The lesions were usually slightly raised, pale tan or reddish, and keratotic; were usually present for less than 1 year; and measured 0.4-2.0 cm. All of them were treated by wide local excision; neither recurrence nor metastasis was reported after 11 to 92 months of clinical followup. Histologically, each TLC was composed of a lobular proliferation centered on the pilar apparatus. Cells with glycogen-rich, mucin-negative, clear or pale eosinophilic cytoplasm predominated. Brisk mitotic activity (4-39 mitoses per 10 high power fields) was typical. Involvement of the interfollicular epidermis was invariably noted, with superficial ulceration in seven tumors. Transitional zones between TLC and the adjacent epidermis were not seen, although pagetoid spread occurred in two examples. Invasion of reticular dermis was present in eight cases, with infiltration to mid-dermis in five TLC. All tumors exhibited areas of tricholemmal type keratinization; dyskeratotic cells were noted in six examples. Hyperkeratosis and parakeratosis were variably present as well. Actinic damage was a constant feature. Despite local invasion at diagnosis, the clinical course of TLC was indolent in all cases.

Endobronchial Richter's syndrome. A rare manifestation of chronic lymphocytic leukemia.

Endobronchial involvement in chronic lymphocytic leukemia is rare. This report describes a patient with chronic lymphocytic leukemia and Richter's syndrome in whom bronchial obstruction occurred due to massive peribronchial lymphadenopathy and endobronchial leukemic infiltrates. Endobronchial Richter's transformation has not been previously reported.

S100 protein immunoreactivity in poorly differentiated carcinomas. Immunohistochemical comparison with malignant melanoma.

This study compares the immunoprofiles of 25 cutaneous and mucosal melanomas with those of 400 poorly differentiated carcinomas, using a polyclonal antiserum to S100 and murine monoclonal antibodies to keratin (KER) and epithelial membrane antigen (EMA). All malignant melanomas expressed S100 but lacked reactivity for KER and EMA. Conversely, all of 49 carcinomas (12%) that displayed S100 also exhibited positivity for both epithelial markers. The latter group of tumors included 17 carcinomas of the breast, 16 eccrine sweat gland carcinomas, five high-grade salivary glandular adenocarcinomas, four lung cancers, three pancreatic ductal carcinomas, two serous ovarian carcinomas, one clear cell adenocarcinoma of the bladder, and one uterine cervical squamous carcinoma. None of 32 epithelial neoplasms that lacked both KER and EMA (19 testicular seminomas, four hepatocellular carcinomas, eight adrenocortical carcinomas, and one Merkel's cell carcinoma) contained S100 protein. These results suggest that S100 protein is relatively nonspecific as a single immunodeterminant in the diagnostic separation of melanoma and anaplastic carcinoma. The concomitant use of stains for EMA and KER, however, obviates this problem. Finally, since it is somewhat restricted in distribution, S100 reactivity in a known carcinoma may be of some use in predicting possible primary sources for a metastasis of unknown origin.

Eccrine sweat gland carcinoma: an histologic and immunohistochemical study of 32 cases.

In an attempt to characterize the immunocytochemical attributes of eccrine sweat gland carcinoma, we studied 32 examples of this tumor with antibodies to epithelial membrane antigen (EMA), cytokeratin (CK), carcinoembryonic antigen, S100 protein, alpha-lactalbumin, salivary amylase, blood group isoantigens, beta-2-microglobulin, and Leu M1. All cases expressed EMA and CK, and 28 of 32 cases also displayed at least 2 of the 6 remaining antigens. No significant variations were noted in the immunophenotypes of histologic subtypes of eccrine carcinoma. These results provide an objective means of diagnostic separation between sweat gland carcinoma and other primary malignant cutaneous tumors. However, they do not appear to correlate with the degree of tumoral differentiation, and are of no assistance in the separation of benign and malignant sudoriferous neoplasms. The ability of immunocytochemical techniques to distinguish between primary malignant adnexal cutaneous tumors and metastases to the skin appears unlikely, but remains to be studied further. Also, the use of immunostaining panels is advised in the study of adnexal carcinomas, since no single determinant in isolation is specific for these neoplasms.

Neuromas of the appendix. A light-microscopic, immunohistochemical and electron-microscopic study of 20 cases.

The neural origin and even the existence of appendiceal neuromas have been questioned. We have studied 20 examples, 7 discovered during a prospective examination of 26 consecutive routine appendectomy specimens (for an incidence of 27%), 2 selected from random cases, and 11 discovered in a retrospective review of 11 randomly selected cases of appendices diagnosed as "fibrous obliteration." By light-microscopy, appendiceal neuromas appear as a loose proliferation of spindle cells usually in a myxoid background, frequently with entrapped fat and connective tissue and infiltrated by eosinophils. Seventeen were located centrally in the appendix without nodule formation. One was central with nodularity and two were confined to the mucosa. The spindle cells were positive for S-100 protein and neuron-specific enolase in all cases. In 12, serotonin positive cells entrapped in the proliferation were present. In 5 of 11 cases with apparent uninvolved appendix present in the specimen, the number of serotonin cells in the crypts was greater than in normal appendix controls. Two appendiceal neuromas contained somatostatin positive cells. Stains for vasoactive intestinal polypeptide, substance P, neurotensin, bombesin and gastrin were negative. Ultrastructural examination of one case confirmed the presence of a mixture of Schwann cells and cells containing neurosecretory granules. We conclude that appendiceal neuroma is a rather common entity, and that most cases of so-called fibrous obliteration actually represent appendiceal neuroma.

Nephroblastoma. A comparative immunocytochemical and lectin-histochemical study.

Nephroblastomas (Wilms' tumors) from a dog, a bird, a pig, and a child were subjected to comparative immunocytochemical and lectin-histochemical analysis along with normal renal tissues from the same animals. Primary rabbit and mouse anti-human antibodies directed at intermediate-filament proteins, neuron-specific enolase, S100 protein, and epithelial membrane antigen were employed, as were biotinylated peanut agglutinin, soybean agglutinin, wheat germ agglutinin, and lectins from Dolichos biflorus and Ulex europaeus. The human neoplasm showed positivity for cytokeratin and epithelial membrane antigen and bound peanut, soybean, and wheat germ agglutinins in epithelial areas. Among the animal tumors, the porcine and canine nephroblastomas showed immunoreactivity for cytokeratin and vimentin in epithelial and blastematous areas, respectively. In addition, they were positive for S100 protein in epithelial foci. All of these results were substantiated by staining patterns in nonhuman kidneys. None of the neoplasms or renal tissues showed reactivity to the other antigens that were assessed. In the porcine tumor, endothelial cells bound D biflorus lectin, and epithelial areas were stained by U europaeus lectin. The avian nephroblastoma bound peanut, soybean, and wheat germ agglutinins, while the canine neoplasm showed no lectin-histochemical reactivity. These data appear to reflect limited immunohistological and histochemical similarities between nephroblastomas of different vertebrates.

Concomitant neuropeptide-producing endometrial carcinomas and ileal carcinoid tumors.

The concomitant occurrence of neuropeptide-reactive endometrial carcinoma and ileal carcinoid tumor represents an observation that has been unreported until now. We have seen two patients with this rare combination of tumors. The endometrial carcinomas in these cases manifested focal immunoreactivity for neuron-specific enolase; in addition, one contained rare cells showing positive staining for gastrin, and the other displayed focal content of substance P. The carcinoid tumors seen in each case demonstrated immunocytochemical positivity for neuron-specific enolase and vasoactive intestinal polypeptide, and one also exhibited immunoreactivity for gastrin. Whether this association of neoplasms represents a syndromic complex or a coincidence is a matter of speculation at present.

Adrenocortical carcinoma. An immunohistochemical comparison with renal cell carcinoma.

The diagnosis of adrenocortical carcinoma (ACC) is often difficult, because this tumor may present with direct extension into adjacent renal parenchyma or with metastatic disease. Renal cell carcinoma and other histologically similar tumors are potentially confused with ACC by conventional light microscopy, and their separation from the latter is often impossible without the aid of additional studies. Furthermore, the distinction between adrenal cortical adenoma and ACC may also be problematic. Because of these factors, the authors studied 10 cases each of ACC, adrenocortical adenoma, and renal cell carcinoma (RCC) immunohistochemically, in an attempt to develop objective parameters which may aid in this differential diagnostic dilemma. Nontrypsinized, formalin-fixed, paraffin-embedded specimens were used in all cases, and tissue from the adrenocortical tumors was also studied for intermediate filament content after protease digestion. All 20 nontrypsinized adrenocortical neoplasms were positive for vimentin, but not for cytokeratin, epithelial membrane antigen, or blood group isoantigens. Conversely, each of 10 cases of RCC expressed epithelial membrane antigen, cytokeratin, and blood group isoantigens, but none was immunoreactive for vimentin. Two adrenocortical carcinomas and three adenomas manifested cytokeratin positivity after trypsin digestion. There were no significant differences between the immunostaining profiles of ACC and adrenocortical adenoma, which suggest that this distinction must still rely upon clinical and morphologic criteria.