Sensitive detection of tumour cells in effusions by combining cytology and fluorescence in situ hybridisation (FISH)

Diagnosis of malignant cells in effusions is important for staging procedures and resulting therapeutic decisions. Cytodiagnostics in effusions is sometimes difficult since reactive mesothelial cells can mimic malignant cells. We used fluorescence in situ hybridisation (FISH) in single-colour or if appropriate in dual-colour evaluation to detect chromosomal aberrations in effusion cells as markers of malignancy, to raise the diagnostic yield. Cytologic and FISH evaluations – by using probes representing several chromosomes always including chromosomes 11 and 17 – were performed in 358 effusion fluids. Cytology was positive for malignancy in 44.4% of all effusions, whereas FISH was positive in 53.9% (P=0.0001). The combination of cytology and FISH was diagnostic for malignancy in 60.9% of effusions. Diagnostic superiority of FISH was demonstrated in effusions from breast cancer, lung cancer, pancreatic cancer, and in effusions from the entire group of gynaecological and gastrointestinal carcinomas. In transudates (effusion protein <2.5 g dl⁻¹), malignant cells were detectable by cytology, FISH, and combined use of both methods in 18.6, 30, and 37.1% of effusions, respectively, suggesting that cytologic and molecular analysis should be performed also with transudates. In conclusion, FISH in combination with conventional cytology is a highly sensitive and specific diagnostic tool for detecting malignant cells in effusions.

The beta subunit of human chorionic gonadotropin lacks specificity for malignant cells in serous effusions

The cytologic diagnosis of malignancy is frequently straightforward. For difficult cases, multiple immunostains and immunostain panels have been investigated without consensus. beta-human chorionic gonadotropin (hCG) has been reportedly expressed in malignancies, but not in normal tissue. HCG also has been reported as a specific marker of metastases in serous fluids when detected with laboratory assays. We investigated the clinical utility of hCG in this cytologic setting. A total of 97 cases of benign and malignant effusions were studied. Each case was immunostained with monoclonal hCG using the avidin-biotin technique and diaminobenzidine as a chromogen. Additionally, a mucicarmine stain was performed on most cases. Cases were evaluated for hCG expression and mucin in a blinded fashion. After the cases were reviewed, the diagnoses were unblinded and staining patterns were evaluated. Of the 47 benign cases studied, 23 (49%) exhibited immunoreactivity to hCG in at least 5% of mesothelial cells present. In contrast, 28 of 44 (64%) adenocarcionomas exhibited a similar degree of immunostaining. In all, 21 (48%) of the adenocarcinomas were also positive for mucin; five of these mucin-positive cases were negative for hCG. The combination of mucin and hCG detected 33 of 44 (75%) adenocarcinomas. We conclude that hCG lacks the specificity for malignant cells to be of clinical use in effusion cytology.

Comparison of different tests to diagnose feline infectious peritonitis

Clinical data from 488 cats (1979–2000) with histopathologically confirmed feline infectious peritonitis (FIP) and 620 comparable controls were evaluated retrospectively to assess the value of several diagnostic tests frequently used in the evaluation of cats with suspected FIP. Diagnostic utility of serum albumin to globulin ratio for the diagnosis of FIP was greater than of the utility of serum total protein and ‐/‐globulin concentrations. Diagnostic utility of these variables was higher when performed on effusion. On effusion, positive and negative predictive values of Rivalta's test, a test that distinguishes between exudates and transudates (0.86 and 0.97), anti‐coronavirus antibody detection (0.90 and 0.79), and immunofluorescence staining of coronavirus antigen in macrophages (1.00 and 0.57) were investigated. The positive and negative predictive values of presence of anti‐coronavirus antibodies were 0.44 and 0.90, respectively, antibody concentrations (1:1,600) were 0.94 and 0.88, presence of immune complexes measured by a competitive enzyme‐linked immunosorbent assay were 0.67 and 0.84, and detection of viral RNA by serum reverse‐transcrip‐tase polymerase chain reaction (RT‐PCR) were 0.90 and 0.47. Effusion RT‐PCR was performed in 6 cats; it was positive in all 5 cats with FIP and negative in the cat with another disease. Diagnostic assays on the fluid in cats with body effusion had good predictive values. Definitive diagnosis of FIP on the basis of measurement of various variables in serum was not possible. Serum tests can only be used to facilitate the decision for more invasive diagnostic methods.

Sequence confirmation of theEWS-WT1 fusion gene transcript in the peritoneal effusion of a patient with desmoplastic small round cell tumor

Desmoplastic small round cell tumor (DSRCT) is a rare undifferentiated neoplasm. The prognosis is poor, even if therapy is instituted promptly, and thus it is important to differentiate it from other histologically and cytologically similar-looking malignancies of the young adult. We present a case of DSRCT in a 17-yr-old male with disseminated peritoneal disease and peritoneal effusion. The cytology sample showed a malignant small round cell tumor, the classical cytological features of DSRCT, and immunohistochemistry performed in the prepared cell block exhibited an antibody expression profile in keeping with DSRCT. Further material from the effusion was prepared for RNA extraction, following which a reverse-transcriptase polymerase chain reaction (RT-PCR) and sequencing of the t(11;22)(p13;q11 or q12) were carried out. The result showed the presence of the reciprocal translocation and thus confirmed the diagnosis of DSRCT. This case shows how molecular techniques (including sequencing) can be applied to cytology in clarifying and confirming certain difficult diagnosis of undifferentiated neoplasms, DSRCT in this particular case.

GLUT1 antibody staining in thin-layer specimens of benign and malignant body cavity effusions

OBJECTIVE

To determine whether GLUT1 antibody could replace one or more of the currently used antiepithelial antibodies and to assess whether ThinPrep methodology is suited to immunocytochemical (ICC) evaluation.

STUDY DESIGN

In a prospective study of 10 fluids containing malignant cells from cases of proven adenocarcinoma and 10 cytologically benign effusions, multiple slides were prepared by ThinPrep technology for staining with four commercially available antibodies and appropriate isotype-matched negative controls. The antibodies used were GLUT1, CEA, B72.3 and Leu-M1 (CD 15). Tissue sections and ThinPrep slides were used as positive controls. Specimens were batched to ensure similar conditions for all antibody reactions.

RESULTS

Of the 11 cases ultimately proven to be carcinoma, GLUT1 and B72.3 stained 7 each (63.6%), and CEA and Leu-M1 6 each (54.5%). No false positive staining was encountered, but one case chosen as a benign control was shown to contain immunopositive cells by three of the four epithelial markers used; this case was therefore an occult true positive rather than a false positive.

CONCLUSION

In this small but controlled prospective analysis, GLUT1 demonstrated strong positive staining, with sensitivity similar to that of currently used epithelial markers. Using GLUT1 in conjunction with B72.3, no cases of carcinoma were missed. GLUT1 could be used in a panel of antibodies designed to confirm the presence of adenocarcinoma. ThinPrep methodology, which enables multiple slides to be prepared after routine microscopy determines the need for ICC, appears suited to this adjuvant investigation.

Utility of thyroid transcription factor-1 and cytokeratin 7 and 20 immunostaining in the identification of origin in malignant effusions

OBJECTIVE

To estimate the utility of thyroid transcription factor-1 (TTF-1) and the combined cytokeratin 7 (CK7) and 20 (CK20) immunoprofile as a marker for identifying the primary site of metastatic adenocarcinoma in effusions of the serous cavity.

STUDY DESIGN

Formalin-fixed, paraffin-embedded cell block specimens of pleural and peritonealfluid diagnosed as metastatic adenocarcinomas with known sites of origin were used for TTF-1, CK7 and CK20 immunohistochemistry. The primary sites of these cases were lung (16 cases), ovary (15), stomach (9), colon (8) and breast (8) and were confirmed by radiologic and/or histologic evaluation.

RESULTS

The lung adenocarcinomas showed TTF-1 positivity in 81% (13/16) of cases. All nonpulmonary adenocarcinomas lacked TTF-1 staining. The CK7-/CK20+ immunophenotype was seen in 63% of colonic adenocarcinomas and not seen in lung, ovary, stomach or breast adenocarcinomas. The CK7+/CK20- immunophenotype was seen in 100%, 88% and 87% of cases that originated in the lung, breast and ovary, respectively.

CONCLUSION

TTF-7 immunostaining is useful in the differentiation between pulmonary and nonpulmonary origin of adenocarcinomas in malignant effusions. The combination of CK7-/CK20+ immunostaining is useful in identifying colon adenocarcinomas.

Use of a panel of markers in the differential diagnosis of adenocarcinoma and reactive mesothelial cells in fluid cytology

To evaluate the use of a panel of markers to differentiate adenocarcinoma and the reactive/inflammatory process in fluid cytology, we stained 29 formalin-fixed, paraffin-embedded cell blocks of effusion fluid from patients with metastatic adenocarcinoma and 24 cell blocks from patients with benign effusion with mucicarmine and antibodies to carcinoembryonic antigen (CEA), B72.3, and calretinin. Positive staining with CEA, B72.3, and mucicarmine was seen in 22 (76%), 20 (69%), and 18 (62%) adenocarcinoma cases, respectively. All except 1 adenocarcinoma was negative for calretinin. No benign cases were positive for B72.3 and mucicarmine. In 1 benign case, scattered epithelial cells demonstrated weak positivity for CEA. The majority of combinations were 100% specific for adenocarcinoma. The highest sensitivity (86%) for adenocarcinomas was achieved with the staining combination of negative for calretinin and positive for any adenocarcinoma marker (CEA, B72.3, or mucicarmine). The use of a panel of markers that recognize adenocarcinoma and mesothelial cells is useful in the differential diagnosis between metastatic adenocarcinoma and the reactive/inflammatory process. The profile of positive staining with at least one of the adenocarcinoma markers and negative calretinin staining is highly specific and sensitive for identifying adenocarcinoma in fluid cytology.

Accuracy of emergency department bedside ultrasonography

OBJECTIVES

To determine which focused ultrasound examinations can be interpreted accurately by emergency physicians who have limited training and experience. To determine whether image quality and/or the operator's level of confidence in the findings correlates with accurate scan interpretation.

METHODS

A prospective sample of consenting adult emergency department patients with the conditions was selected for study. Scans were performed by emergency physicians who had attended a 3-day focused ultrasound examinations instruction course. All scans were videotaped and subsequently reviewed by a radiologist. Accuracy was determined by comparing the emergency physicians scan interpretation with preselected gold standards. Chi-squared tests were employed to determine if the individual performing the scan, the type of scan, patient's body habitus, image quality and/or operator confidence were reliable predictors of accuracy.

RESULTS

Between September 1997 and January 1999, 221 scans were studied. Accuracy varied widely depending on the type of scan performed: aortic scans were 100% accurate whereas renal scans had 68% accuracy. On bivariate analyses, there was little variation in the various operators' levels of proficiency and accuracy of interpretation was not associated with patient body habitus, image quality or operator confidence.

CONCLUSIONS

Neophytes can accurately perform and interpret aortic scans; additional training and/or experience appear to be necessary to achieve proficiency in conducting most of the other scans studied. Inexperienced operators are unable to discern whether their scan interpretations will prove accurate.

Aggressive uterine sarcoma with rhabdoid features: diagnosis by peritoneal fluid cytology and absence of INI1 gene mutation

We report a primary uterine sarcoma with classic histologic, immunohistochemical, and ultrastructural features of a malignant extrarenal rhabdoid tumor (MERT). It arose in a 71-year-old woman who presented with postmenopausal bleeding, ascites, and a right pelvic mass. Malignant cells with rhabdoid morphology were identified by cytologic examination of the peritoneal fluid. Exploratory laparotomy revealed a 10-cm right adnexal mass and disseminated peritoneal tumor. Pathologic study showed diffuse expansion of the endometrial stroma by rhabdoid-like cells with transmural infiltration of the myometrium and extensive involvement of uterine serosa and right ovary by tumor. Neoplastic cells were immunoreactive for vimentin, cytokeratin, and epithelial membrane antigen, and cytoplasmic whorls of intermediate filaments were observed by electron microscopy. Fluorescence in situ hybridization (FISH) studies with chromosome 22-specific probes showed no loss of the INI1 gene, and no coding sequence mutation was identified.

Hyponatremia and hyperkalemia associated with peritoneal effusion in four cats

Four cats with considerable peritoneal effusion and corresponding hyponatremia and hyperkalemia were evaluated. The Na:K ratio in all cats was < 25, which is suggestive of adrenal insufficiency. An ACTH stimulation test was performed on 3 cats for evaluation of adrenal gland function. Serum cortisol and aldosterone concentrations did not support a diagnosis of adrenal gland insufficiency. In 1 cat, histologic evaluation of the adrenal glands at necropsy also failed to support a diagnosis of hypoadrenocorticism. On the basis of these findings, and because hyponatremia and hyperkalemia could not be readily explained by another cause, the electrolyte abnormalities were presumed to be secondary to peritoneal effusion.

Ascitic fluid cytology of adenosarcoma of the ovary: a case report

Extrauterine adenosarcoma is very rare and originates in the ovary, adnexa, or myometrium. Cytologic study of ascites is very important to determine clinical staging of malignant ovarian tumors and provide adequate therapy for recurrence. The cytomorphologic features of adenosarcoma have been only rarely described. A 77-yr-old woman visited a hospital with a complaint of lower abdominal pain for 1 mo. A tumor originating from the right adnexa in the pelvis, and involving the rectum, was found in surgery. In the ascitic fluid cytology, a few dispersed tumor cells with large cytoplasm and nuclei were oval-shaped, with nuclear invagination. The chromatin was finely granular; one or two nucleoli were conspicuous. To our knowledge, this is the fifteenth reported case of adenosarcoma of the ovary, and there have been no prior reports describing the cytological features of ascitic fluid cells in adenosarcoma of the ovary.

Cytologic clue of so-called nodular histiocytic hyperplasia of the pleura

So-called "nodular histiocytic hyperplasia" (NHH) is a benign histiocytic lesion caused by mechanical irritation, inflammation, and tumor. Frequently, it has been confused with mesothelial lesions and other malignant neoplasms. The diagnostic clue is proliferating cells in the lesion showing diffuse, strong immunoreactivity against the histiocytic marker, CD68. Recently, we encountered a case of so-called NHH of the pleura and confused it with various malignant neoplasms on histologic examination. An 80-yr-old Korean female presented with ascites, pleural effusions, and nodules on the pleural base. Both ascites and pleural effusion tapping smears displayed moderate cellularity, vaguely nodular cellular aggregates mainly composed of mononuclear cells with bland morphology, entrapped mesothelial cells, and background lymphocytes. Pleural biopsy demonstrated vaguely nodular, compact cellular aggregates of reactive histiocytes which were immunoreactive against CD68. Based on our case, cytologic examination as well as immunohistochemical study should be stressed in the case of so-called NHH. They can provide us more credible morphologic clues to reach a more accurate diagnosis than histologic examination alone, and we can avoid invasive procedures or unnecessary therapies to patients. To our best knowledge, this is the first report describing the cytologic features of so-called NHH in the English-language literature.

Gene expression analysis of the catalytic subunit of human telomerase (hEST2) in the differential diagnosis of serous effusions

Diagnostic accuracy in effusion cytology based on morphologic examination is not always satisfactory. Therefore, various diagnostic adjuncts such as immunocytochemistry or deoxyribonucleic acid cytometry are employed in this diagnostic field. Recently, demonstration of telomerase activity has been proposed as a possible marker for malignancy. In this study a seminested reverse transcription-polymerase chain reaction (RT-PCR) strategy for expression analysis of the catalytic subunit of human telomerase (hEST2) was used in 58 serous effusions. RT-PCR results correlated with cytologic diagnoses in 14 of 17 malignant effusions. In eight effusions cytologically suspicious for malignancy, PCR results were in accordance with the clinical follow-up. However, hEST2 RT-PCR was also positive in six of 15 cytologically benign effusions that consisted predominantly of inflammatory and mesothelial cells. Using the telomeric repeat amplification protocol, it could be demonstrated that cultured, proliferating benign mesothelial cells may present a weak telomerase activity, as is known in other benign cells including activated lymphocytes. In conclusion, the simple and rapid method of hEST2 RT-PCR serves to support the cytologic diagnosis of malignancy, but false-positive PCR results resulting from activated lymphocytes and proliferating mesothelial cells must be considered.

Detection of malignant effusions: comparison of a telomerase assay and cytologic examination

Telomerase is inactive in most somatic cells, but has been found to be reactivated in a majority of cancers. Our principal goal was to test whether the presence of telomerase activity concurred with positive cytology, and was thus of potential use in detecting cancer cells in effusions. The telomeric repeat amplification protocol (TRAP) assay and cytological examination were performed in a blinded fashion on 91 unselected effusions, for which laboratory processing was done according to standard procedures. In our series, 30% (27/91) of samples were found to be malignant by cytology. Of these, 19 (70%) were also positive in the TRAP assay. Of the 8 telomerase-negative cytology-positive samples, RNA integrity was generally poor, indicating suboptimal sample conservation for molecular analysis. Negative cytology in the presence of telomerase activity was observed in 17 effusions. Of these, 11 were from patients with advanced cancer, and thus a diagnosis of malignant effusion should be suspected. The TRAP assay for telomerase activity holds promise in the analysis of effusions, but its routine use as an adjunct to cytology awaits further confirmation of its positive predictive value.

Characterizing subpopulations of neoplastic cells in serous effusions. The role of immunocytochemistry

OBJECTIVE

To analyze the role of immunochemistry in serous effusions.

STUDY DESIGN

We analyzed cell blocks of 18 pleural and 18 peritoneal effusions diagnosed as malignant (18), benign (14) and suspicious (4). They were immunostained by the avidin-biotin complex method with a panel of four monoclonal antibodies--CEA, Ber-EP4, LeuM1 (CD15) and p53--and, for lectins (Ulex europaeus) UEA-l, ConA and ConBr.

RESULTS

Seventeen of the 18 cases of adenocarcinoma were positive for CEA (95%), 12 (66.6%) for Ber-EP4, 11 (61%) for CD15 and 11 (61%) for p53. Twelve of the 18 (66.6%) were positive for UEA-1, CEA, Ber-EP4 and CD15. UEA-1 did not react with mesothelial cells. p53 Gave a positive reaction in only one case, reactive mesothelial cells. ConA and ConBr reacted indiscriminately with benign and malignant cells; thus, it was not useful in distinguishing between these cells.

CONCLUSION

In this context no antibody used alone is reliable for corroborating a diagnosis, but the selective use of a small panel of three markers (CEA, Ber-EP4 and LeuM1) can be very useful in solving diagnostic difficulties in the cytodiagnosis of serous effusions.

Serum-effusion albumin gradient in dogs with transudative abdominal effusion

A prospective clinical study in dogs with transudative abdominal effusions examined the clinical usefulness of the serum albumin-effusion albumin (SA-EA) gradient. In humans, the SA-EA gradient facilitates classification of abdominal effusion, with a gradient > or = 1.1 indicating the presence of portal hypertension. Gradient values proved useful for predicting therapeutic response to sodium restriction and diuresis in humans. Of 49 dogs evaluated, 25 had hepatobiliary disease (group 1) and 24 had other nonhepatobiliary conditions (group 2). Portal hypertension was clinically suspected in 24 of 25 dogs in group 1 and in 15 of 24 dogs in group 2. A broad range of SA-EA gradients was found. A gradient > or = 1.1 was found in 22 of 25 (88.0%) dogs with liver disease and in 14 of 24 (58.3%) dogs with other disorders. The median SA-EA gradient was higher in group 1 than in group 2, with values of 1.4 (range, 0.7-3.1) and 1.1 (range, 0.3-2.6), respectively (P < .04). Considerable overlapping of SA-EA gradients occurred between groups and among dogs with diverse conditions such that gradient values could not distinguish dogs with hepatobiliary disease from dogs with other conditions. The overall diagnostic accuracy of the SA-EA gradient in predicting portal hypertension in dogs with and without hepatobiliary disease (69.4%) exceeded that of hypoalbuminemia (57.1%). These findings suggest that portal hypertension is a predominant force in formation of transudative abdominal effusion in dogs with hepatobiliary disease and in dogs with other disorders. Whether the SA-EA gradient can be used to guide therapeutic mobilization of effusion in dogs remains to be proved.

[Burkitt's lymphoma occurring as a primary lymphomatous effusion]

A 39-year-old man was admitted with massive ascites. Specimens of ascitic fluid contained numerous cells with a FAB-L3 appearance, and small noncleaved cell lymphoma morphology. These cells expressed CD10, CD19, CD20, CD38, CD45, HLA-DR, and IgM antigens, and were positive for IgM and c-myc protein in cytoplasmic immunostaining tests. Clonal rearrangements of IgH and c-myc genes were detected by Southern blot analysis. No mass lesions were found by physical examination, and systemic computed photography did not reveal enlargement of lymph nodes, spleen, or liver. Bone marrow aspiration showed no infiltration of malignant cells. Ga scintigraphy indicated hot lesions only in the abdomen. These findings suggested that Burkitt's lymphoma had developed in the peritoneal cavity as a primary lymphomatous effusion. Chemotherapy with methotrexate, cyclophosphamide, vincristine, doxorubicin, etoposide, and dexamethasone was effective, and the patient has been free from the disease for 1 year since completion of consolidation treatment with autologous peripheral blood stem cell transplantation.

Telomerase enzyme activity as a diagnostic tool to distinguish effusions of malignant and benign origin

Telomerase enzyme activity is high in populations of cells that are dividing, and is low or undetectable in quiescent cell populations. Activation of telomerase in tissues that normally lack the capacity for self-renewal is strongly correlated with neoplasia. Telomerase activity can be detected in samples containing very small numbers of cells and studies of human patients suggest that measurement of telomerase activity may be useful for the evaluation of samples that can be obtained in a minimally invasive manner. This study compares the presence or absence of telomerase activity with cytologic evaluation of body cavity effusions, to determine if neoplasia is the underlying cause for the effusion in dogs and cats. Detection of telomerase in effusions was no more sensitive than cytologic evaluation for the identification of underlying neoplasia, and was less specific (telomerase assay: sensitivity = 50%, specificity = 83%; cytology: sensitivity = 50%, specificity = 100%). We conclude that although the telomerase assay may constitute a useful adjunctive test for the diagnosis of neoplasia in some dogs and cats with body cavity effusions, the results of this assay are not sufficiently reliable to be used as a sole diagnostic test.

Diagnostic accuracy of effusion cytology

The aim of this investigation was to report on the diagnostic accuracy of conventional effusion cytology. Cytological diagnoses of 300 pleural effusions and 300 ascites were compared with clinical and/or histological follow-ups of the respective patients. Sensitivity of our cytological diagnoses on pleural effusions was 50.0%, specificity 97.0%, positive predictive value 95.7%, and negative predictive value 86.4%. Sensitivity in ascitic effusions was 62.4%, specificity 98.0%, positive predictive value 100.0%, and negative predictive value 88.3%; 5.8% of diagnoses for pleural and 4.4% for peritoneal effusions were suspicious or doubtful. The overall false-positive rate was 0.5%, while the false-negative rate was 31.5%. False-negative results were due to sampling errors in 71% of pleural and 73% of peritoneal effusions and to screening errors in 29% and 27%, respectively. Our data and those from the literature show that diagnostic accuracy of effusion cytology is still unsatisfactory and should be improved. Therefore, the use of different adjuvant methods is recommended.

Thoracic and abdominal blastomycosis in a horse

A 5-year-old Quarter Horse mare was examined because of lethargy, fever, and weight loss of 1 month's duration. Thoracic auscultation revealed decreased lung sounds cranioventrally. Thoracic ultrasonography revealed bilateral anechoic areas with hyperechoic strands, consistent with pleural effusion and fibrin tags. A large amount of free fluid was evident during abdominal ultrasonography. Abnormalities included anemia, hyperproteinemia, hyperglobulinemia, hyperfibrinogenemia, and hypoalbuminemia. Thoracic radiography revealed alveolar infiltrates in the cranial and caudoventral lung fields. A cavitary mass, consistent with an abscess, could be seen caudodorsal to the crura of the diaphragm. Ultrasonographic evaluation of this area revealed a hypoechoic mass with septations. Bilateral thoracocentesis was performed. Bacterial culture of the pleural fluid did not yield growth, but Blastomyces dermatitidis was isolated from pleural fluid, abdominal fluid, and an aspirate of the abscess. The mare was euthanatized, and a diagnosis of thoracic and abdominal blastomycosis was confirmed at necropsy.

Differential diagnostic significance of the paucity of HLA-I antigens on metastatic breast carcinoma cells in effusions

Distinction between benign reactive mesothelial cells and metastatic breast adenocarcinoma cells in effusions from patients with a known prior history of breast cancer is not the easiest task in diagnostic pathology. Here, we report the usefulness of testing the expression of class I HLA antigens (HLA A, B, C) in this respect. Cytospins were prepared from effusions of patients without the history of breast cancer (5 cases) and from effusions of patients with infiltrating ductal carcinoma (11 cases). Three effusions from cancerous patients were not malignant cytologically. The expression of HLA-A, B, C, HLA-DR and beta2-microglobulin as well as the macrophage antigen, CD14, was evaluated by immunocytochemistry. In 10 of 11 effusions the cytologically malignant cells expressed very weak or undetectable HLA-A,B,C as compared to the mesothelial cells and macrophages. The paucity of expression of HLA-A, B, C was detectable in those 3 cases where a definitive cytological diagnosis of malignancy could not be established. In contrast, mesothelial cells and macrophages from all samples were uniformly and strongly positive for both HLA-A, B, C and beta2-microglobulin. We conclude that the paucity of HLA-I antigens provides a marker helpful in distinguishing metastatic breast carcinoma cells from reactive mesothelial cells in effusions.

Peritoneal effusion in cats: 65 cases (1981-1997)

OBJECTIVE

To determine signalment, diagnoses, presence of effusions in multiple sites, and outcome in cats with peritoneal effusion.

DESIGN

Retrospective case series.

ANIMALS

65 cats.

PROCEDURE

Medical records from 1981 to 1997 were reviewed to obtain information on cats with peritoneal effusion identified on physical examination, radiographs, abdominal ultrasonograms, or at necropsy.

RESULTS

Conditions most commonly associated with peritoneal effusion in cats, in order of frequency, were cardiovascular disease, neoplasia, hepatic disease, renal disease, feline infectious peritonitis, peritonitis attributable to other causes, and urinary tract trauma. Dilated cardiomyopathy (DCM) was the most common disease associated with peritoneal effusion; however, DCM was diagnosed in most of these cats before taurine deficiency was found to be a primary cause of this form of cardiomyopathy in cats. Neoplasia was the most common cause after 1987. Right-sided congestive heart failure was the most commonly associated disorder in cats < 1 year old, whereas neoplastic disease was more common with increasing age. Most effusions were detected during the initial physical examination and were modified transudates. Peritoneal effusion was commonly accompanied by fluid accumulation elsewhere, particularly pleural effusion. The prognosis for a cat with abdominal effusion in this study was poor (mean survival time, 21 days; range, 1 to 350 days; median, 2.5 days).

CLINICAL IMPLICATIONS

The primary differential diagnosis for peritoneal effusion in cats is neoplastic disease in older cats and right-sided heart failure in kittens. Diseases associated with peritoneal effusion generally have poor prognoses.

Static DNA cytometry as a diagnostic aid in effusion cytology: II. DNA aneuploidy for identification of neoplastic cells in equivocal effusions

OBJECTIVE

The sensitivity of conventional cytology for identification of neoplastic cells in effusions is unsatisfactory, about 58%. The rate of diagnostically equivocal effusions in routine cytology is about 6%. DNA aneuploidy has previously been proven to be a sensitive and specific marker for the identification of tumor cells in effusions. In the present study we determined if malignancy can be identified in cytologically equivocal cells in effusions using DNA aneuploidy as a marker, thus decreasing the rate of cytologically equivocal diagnoses in effusions.

STUDY DESIGN

One hundred cytologically equivocal effusions of the serous cavities were obtained from routine diagnostic material. Nuclear DNA content was measured after Feulgen staining using a TV image analysis system. Data were correlated with patient follow-up.

RESULTS

DNA aneuploidy was assumed if abnormal DNA stemlines, a coefficient of variation of the first DNA stemline > or = 10% or cells > 9c were observed. The sensitivity of DNA aneuploidy for the identification of malignancy was 55.9%. Specificity of DNA nonaneuploidy for benignity was 94.1%. The positive predictive value of the marker DNA aneuploidy for the occurrence of malignant cells was 97.9% since all but one DNA aneuploid case showed malignancy in follow-up.

CONCLUSION

Image cytometry applying DNA aneuploidy as a parameter is able to detect the occurrence of malignant cells in cytologically equivocal effusions in about every second case. Thus, this method is able to increase diagnostic accuracy of conventional effusion cytology by decreasing the rate of diagnostically equivocal effusions.

Static DNA cytometry as a diagnostic aid in effusion cytology: I. DNA aneuploidy for identification and differentiation of primary and secondary tumors of the serous membranes

OBJECTIVE

To determine whether DNA aneuploidy is a sensitive and specific marker for the identification of tumor cells in effusions and whether the pattern of DNA aneuploidy can provide important information for the differential diagnosis of primary and secondary tumors of the serous membranes.

STUDY DESIGN

One hundred eight malignant mesotheliomas as well as 102 metastatic carcinomas of the serous membranes were obtained from routine cytologic and histologic material. One hundred reactive effusions were investigated as controls. Nuclear DNA contents were measured after Feulgen staining using a TV image analysis system.

RESULTS

DNA aneuploidy was assumed if abnormal DNA stemlines, a coefficient of variation of the first DNA stemline > or = 10%, or cells > 9c were observed. On this basis the prevalence of DNA aneuploidy in mesotheliomas was 83% for cytologic and 84% for histologic material. In effusions of metastatic carcinomas it was 100%. None of the 100 reactive effusions revealed DNA aneuploidy (prevalence, 0%). Positive predictive value for mesotheliomas was 100%; negative predictive value was 88% for cytologic and 82% for histologic material. Positive predictive value for metastatic carcinomas was 100%; negative predictive value was 100%. Seventy-two percent of the mesotheliomas revealed their greatest stemline within the range 1.80c-2.20c, whereas none of the metastatic carcinomas showed this stemline position.

CONCLUSION

DNA image cytometry might be a very sensitive and highly specific, additional tool for identification of neoplastic cells in effusions as well as for the differential diagnosis of mesothelioma vs. metastatic carcinoma of the serous membranes.

Comparison of conventional microscopy and digitized imaging for diagnosis in serous effusions

OBJECTIVE

To compare diagnoses made from conventional microscopy and digitized imaging in preparation for teleconsultation cytopathology services that are affordable and efficient.

STUDY DESIGN

One hundred six consecutive serous effusions received in the cytopathology laboratory of a general hospital in Porto Alegre, RS, Brazil, were studied. The diagnoses by the senior cytopathologist at the conventional microscope were considered the standard and identified 61 cases negative and 45 positive for malignant cells (40 epithelial and 5 nonepithelial). The same pathologist digitized 461 selected fields for analysis by a second experienced cytopathologist (observer A) and a senior cytotechnologist (observer B) without knowledge of the standard diagnoses. Ten cases were studied in daily sessions of one hour each. The diagnoses were negative for malignant cells, positive for malignant cells (epithelial) and positive for malignant cells (nonepithelial).

RESULTS

The following kappa values were found: 0.91 (observer A and observer B versus standard) and 0.86 (observer A versus observer B).

CONCLUSION

Remote digitized imaging diagnosis in serous effusions is possible and has a high degree of concordance with diagnosis by conventional microscopy. Similar studies involving a larger group of cytopathologists and cytotechnologists should be done to identify interobserver variability.

DNA ploidy and proliferating cell nuclear antigen image analysis of peritoneal and pleural effusions. A possible diagnostic role

OBJECTIVE

To determine the role of DNA and proliferating cell nuclear antigen (PCNA) image analysis (IA) in enhancing the diagnostic sensitivity of conventional cytology (CC).

STUDY DESIGN

The histopathologic and clinical data on 87 consecutive pleural and peritoneal effusions were used to evaluate the accuracy of CC and DNA IA results.

RESULTS

CC showed a sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of 65%, 100%, 100% and 62%, respectively. Aneuploidy peaks were seen in 49 cases; 47 of them were true positives. Thirty of 38 diploid cases were true negatives. The sensitivity, specificity, PPV and NPV were 85%, 94%, 96% and 80%, respectively. There were positive correlations between DNA ploidy profile and PCNA proliferative index (PI), (R = .697) and significant differences in PCNA PI between malignant and benign effusions (P < .001).

CONCLUSION

The DNA IA PI by PCNA can be used as a complementary diagnostic tool with CC in cytologically inconclusive cases.

Effusive-constrictive pericardial disease secondary to osseous metaplasia of the pericardium in a dog

Osseous metaplasia of the pericardium causing effusive-constrictive pericardial disease has not, to our knowledge, been reported in dogs. Clinical signs of right-sided congestive heart failure prompted examination of the dog of this report. Documented causes of constrictive pericardial disease in dogs include trauma and actinomycotic, mycobacterial, and fungal infections. These causes were ruled out in this dog. Immune-mediated disorders, as have been reported in people, also were considered unlikely on the basis of test results. It was concluded that this dog had idiopathic osseous metaplasia of the pericardium and pleura. Signs of right-sided congestive heart failure resolved after subtotal pericardiectomy was performed.

Malignant mesothelioma: immunohistochemistry and DNA ploidy analysis as methods to differentiate mesothelioma from benign reactive mesothelial cell proliferation and adenocarcinoma in pleural and peritoneal effusions

OBJECTIVE

To determine whether malignant mesotheliomas can be differentiated from adenocarcinomas and benign reactive mesothelial cells in pleural and peritoneal fluids using immunohistochemical analysis in conjunction with DNA ploidy analysis.

DESIGN

Sixteen cases of malignant mesothelioma, including epithelial, sarcomatous, and biphasic types, were collected. DNA analysis using flow cytometry and/or image analysis was performed on paraffin-embedded tissue from 15 of the mesothelioma cases, as well as on cytospin cell preparations from samples of pleural and peritoneal fluids from cases with either cytologically proven adenocarcinoma (seven cases) or benign reactive mesothelial cells (seven cases). Immunohistochemical studies were done in 15 mesotheliomas, 5 adenocarcinomas, and 4 benign reactive mesothelial cell effusions.

RESULTS

All malignant mesotheliomas tested (100%) stained positively for prekeratin, whereas stains for carcinoembryonic antigen, B72.3, Leu-M1, and Ber-EP4 were negative. Stains vimentin, epithelial membrane antigen, and CA125 were positive in 75%, 75%, and 25% of cases tested, respectively. Benign reactive mesothelial cell cases stained similarly. Adenocarcinomas were more likely to react positively with B72.3, Ber-EP4, and carcinoembryonic antigen, and negatively with vimentin. DNA analysis showed that all benign cases were diploid, while all adenocarcinomas were nondiploid. Fifty-three percent of the malignant mesotheliomas were nondiploid. Sensitivity for detection of nondiploidy was greater for image analysis than for flow cytometry (100% vs 75%).

CONCLUSIONS

B72.3, Ber-EP4, carcinoembryonic antigen, and vimentin are useful immunohistochemical markers in differentiating malignant mesotheliomas from adenocarcinomas, whereas immunohistochemistry does not reliably distinguish malignant from benign hyperplastic mesothelial cells. The addition of DNA ploidy studies is useful for differentiating the latter two groups.

[Pancreatic and extrapancreatic fluid collections following acute and chronic pancreatitis]

Intra- or extrapancreatic liquid collections are common complications for acute and chronic pancreatitis, with variable morphologic features and possible evolution toward complications. A total of 31 liquid collections (pseudocysts, ascites and/ or enzymatic pleurisy) in 22 patients are presented. The study assems the etiology, the diagnostic methods and the treatment of the liquid collections. The preferred surgical treatment is either cysto-digestive anastomosis or distal pancreatic resections. Also some new therapeutic modalities are analyzed percutaneous or endoscopic drainage.

The value of adenosine deaminase (ADA) determination in the diagnosis of tuberculous ascites

In order to evaluate the role of the determination of adenosine deaminase activity (ADA) in ascitic fluid for the diagnosis of tuberculosis, 44 patients were studied. Based on biochemical, cytological, histopathological and microbiological tests, the patients were divided into 5 groups: G1-tuberculous ascites (n = 8); G2-malignant ascites (n = 13); G3-spontaneous bacterial peritonitis (n = 6); G4-pancreatic ascites (n = 2); G5-miscelaneous ascites (n = 15). ADA concentration were significantly higher in G1 (133.50 +/- 24.74 U/l) compared to the other groups (G2 = 41.85 +/- 52.07 U/l; G3 = 10.63 +/- 5.87 U/l; G4 = 18.00 +/- 7.07 U/l; G5 = 11.23 +/- 7.66 U/l). At a cut-off value of > 31 U/l, the sensitivity, specificity and positive and negative predictive values were 100%, 92%, 72% and 100%, respectively. ADA concentrations as high as in tuberculous ascites were only found in two malignant ascites caused by lymphoma. We conclude that ADA determination in ascitic fluid is a useful and reliable screening test for diagnosing tuberculous ascites. Values of ADA higher than 31 U/l indicate more invasive methods to confirm the diagnosis of tuberculosis.

A prospective study of emergent abdominal sonography after blunt trauma

In North America, the role of emergent abdominal sonography [ultrasonography (US)] after blunt trauma requires further definition. The purpose of this prospective study was to compare US to the gold standards, diagnostic peritoneal lavage (DPL), and computed tomography (CT), in a population of adults after blunt trauma. In 206 adults who required either CT or DPL to assess possible abdominal injury, US was performed, before DPL or CT, and was aimed at the detection of intraperitoneal fluid. The mean Injury Severity Score and Glasgow Coma Scale score were 24.0 and 11.9, respectively. One hundred thirty-seven patients (67%) had CT and 69 (33%) had DPL. The positive and negative predictive values of US for intraperitoneal fluid were 90% and 97%, respectively. The sensitivity, specificity, and accuracy of US for free fluid were 81%, 98%, and 96%, respectively. Of the six false-negative USs, only one required surgery. The US examinations required 2.6 +/- 1.4 min. Emergent abdominal sonography is an accurate, rapid test for the presence of intraperitoneal fluid in adult blunt trauma victims and in these patients may prove valuable as a screening test for abdominal injury.

Neural networks as an aid in the diagnosis of lymphocyte-rich effusions

Neural network (NN) technology was applied to digital image analysis data for 112 Papanicolaou-fixed and -stained smears of lymphocyte-rich effusions (LREs). The smears were analyzed with an inexpensive image analysis system assembled in our laboratory. Several models were developed using backpropagation NN development software in an effort to optimize classification of the LREs as reactive lymphocytosis or malignant lymphoma and to analyze the effects of various parameters on classification rates. The greatest specificity and sensitivity of LRE classification were achieved with NN models that consisted of 7 input neurons, including 5 morphometric and 2 densitometric variables, 10 hidden-layer neurons and 1 output neuron. This NN architecture with a sigmoidal transfer function provided a true cross-validation rate of 89.3% of testing data, with a sensitivity of 76.9%, specificity of 93.0% and shrinkage of 10.7%. The same NN architecture with a step transfer function provided a true cross-validation rate of 95.3%, sensitivity of 85.7%, specificity of 97.6% and shrinkage of 0%. The effects of various parameters, such as network size, shrinkage and ratio of sample size to input layer size, on NN accuracy are discussed.

Cytogenetic analysis of effusions from malignant mesothelioma. A diagnostic adjunct to cytology

Most patients with malignant mesothelioma (MM) present with an effusion, but distinguishing malignant from reactive mesothelial cells by conventional cytology may be difficult. We investigated the possibility of identifying clonal cytogenetic aberrations in pleural or peritoneal fluid from 10 patients with a clinical suspicion of MM. Direct metaphase harvests and short-term cultures were performed on fresh fluid. Clonal cytogenetic aberrations indicative of malignancy, with findings previously reported in association with mesothelioma, were found in all patients; these included del(1p), del(3p) and del(22q). Cytologic examination of the effusions showed malignant cells consistent with MM in 5 patients and atypical mesothelial cells suggestive of MM in 4. In one case the cytology of several samples of pleural fluid was within normal limits. Subsequent histology confirmed the diagnosis of MM in 9 of the 10 patients; medical complications precluded tissue biopsy in the 10th. We conclude that the cytogenetic analysis of effusions may be a useful and reliable adjunct to cytology in the diagnosis of MM.

Role of immunoperoxidase staining in serous effusions

Immunoreactivity with monoclonal antibodies against epithelial membrane antigen, vimentin, keratin-squamous epithelium, keratin-nonsquamous epithelium and with polyclonal antibodies against keratin, involucrin, S-100 protein, desmin and varies; is directly proportional to-1 antitrypsin was done in 30 pleural and peritoneal effusion fluids; 15 each of benign and malignant origin using the avidin-biotin-peroxidase complex (ABC) technique to differentiate between the mesothelial cells and the adenocarcinoma cells. In the present study we have demonstrated that desmin and S-100 protein are distributed in the cancer cells and the mesothelial cells of the effusion fluids. Neither EMA nor keratin has the specific reactive pattern which could lead to the differentiation of the mesothelial cells from the cancer cells, but vimentin and keratin could be used for the diagnosis of the mesothelial cells since they had maximum reactivities compared to the cancer cells.

MR imaging of pleural and peritoneal effusion

The purpose of this study was to assess the efficacy of MR imaging in predicting the quality of ascites and pleural effusion. MR examinations of 20 patients with different benign or malignant diseases accompanied with ascites or pleural effusion were retrospectively studied. Results were compared with histopathological findings. On T1- and T2-weighted images, the MR intensity of the effusion depended mainly on the concentration of protein, whereas on gradient echo images, it depended mainly on the concentration of blood. MR examination was useful in non-invasively differentiating exudative or hemorrhagic effusion from serous effusion. Knowledge or inference of the quality of effusion can direct MR interpretation and may improve diagnostic accuracy.

Ancillary tests for assessment of the ruminant digestive system

This article reviews the ancillary tests that are available to evaluate disease and function of the gastrointestinal system. Procedures and tests such as abdominocentesis and peritoneal fluid cytology; rumen fluid analysis; abomasal pH and pepsinogen; upper digestive tract endoscopy; ultrasonography and radiology; hematologic and biochemical assessments; cytology, culture, and histopathology of aspirates; serology, liver function tests and biopsy; exploratory laparotomy; fecal examination; and microbiology are described.

AUA1: new immunocytochemical marker for detecting epithelial cells in body cavity fluids

Further to detailed genetic and biochemical characterisation of AUA1 as a surface glycoprotein present on epithelial cells, the antibody against AUA1 was used as an immunocytochemical marker of epithelial cells in body cavity fluids in an attempt to improve the diagnosis made on routine staining. AUA1 was initially tested in 144 morphologically clear cut effusions. It was positive in 46 of 52 (88%) carcinomas and negative in 82 of 84 (98%) benign effusions, including technically inadequate or poorly cellular preparations. There were no false positive results. AUA1 was subsequently used more selectively--that is, in 42 of 175 (24%) of morphologically difficult fluids. AUA1 provided essential diagnostic information in 15 of 42 (36%) and confirmed diagnosis in 17 of 42 (40%), thus enabling accurate diagnosis in a further 32 of 42 (76%) of the difficult cases. The total diagnostic accuracy was therefore 94.3%. AUA1 is a reliable immunocytochemical marker for detecting epithelial cells in body fluids. Its use improves diagnostic accuracy of morphological assessment in difficult cases.

Detection of a soluble antigen defined by monoclonal antibody 83D4 in serous effusions associated with breast carcinoma

Monoclonal antibody (MoAb) 83D4 was generated by immunization with cell suspensions obtained from sections of formol-fixed paraffin embedded human breast cancer. It recognized an antigen expressed in breast carcinomas but not in normal breast tissue. Pleural and ascitic fluids from 66 patients were studied by an 83D4 heterologous sandwich radioimmunoassay (SRIA) using solid-phase immobilized wheat germ agglutinin to detect the 83D4 soluble antigen. Using a cutoff level of 5 units/ml of 83D4 antigen, higher values were found in 22 of 27 breast cancer-associated effusions (mean = 10.72 +/- 6.80 units/ml). The 20 nonmalignant effusion fluids tested showed lower values (mean = 1.16 +/- 1.49 units/ml, P less than 0.001). The antigen was undetectable or present in low levels in effusions from patients with hematologic malignancies. When SRIA results were compared with conventional cytologic diagnosis in breast-cancer effusions, elevated levels of 83D4 soluble antigen were found in all patients (8 of 8) in whom malignant cells had been detected, in 4 of 8 patients with the diagnosis of "suspected malignancy," and in 10 of 11 patients with negative cytologic findings. Using an immunoglucosidase method on cell smears of various origins, MoAb 83D4 stained metastatic cells of breast and ovary carcinomas but did not reactive with mesothelial cells and other normal or malignant cell types. These results suggest that quantitation of the 83D4 soluble antigen may be used to improve the diagnosis of cancer in serous effusions.

Ultrasonically guided percutaneous drainage of abdominal fluid collections: a long-term study of its therapeutic efficacy

Fifty patients underwent ultrasonically guided percutaneous drainage (US-GPD) either with needle aspiration or catheter drainage. The procedures resulted in 70% complete recovery, 20% partial success and 10% of failures. The same patients were followed with clinical examination and sonography for a mean time of 36.3 months (minimum follow-up: 12 months). During the follow up period, 10 relapses occurred and one patient, considered for surgery after partial percutaneous treatment of a pyogenic liver abscess, recovered completely under conservative treatment. An analysis of the factors potentially related to the recurrence was made. It was found that one-step needle aspiration of abdominal abscesses and percutaneous treatment of chronic pancreatic pseudocysts are more prone to relapses. We conclude that US-GPD is an efficacious therapy for abdominal fluid collections, but an adequate drainage technique and a careful selection of the patients is crucial to avoid the possibility of relapse.

[The enhancement phenomenon of serous cavity effusions]

The enhancement of ascites following a high dose of contrast medium has been recently described. The CT behavior of 26 peritoneal, pleural or pericardial effusions has been studied in 23 patients after the administration of a high dose of urographic contrast medium. The effusions were enhanced in all patients but one. No difference between malignant and non-malignant effusions could be observed with ionic and non-ionic contrast medium. Low molecular weight of the urographic contrast medium (600-800 daltons) can explain the free passage of the solute through peritoneum, pleura, and pericardium. The knowledge of such a phenomenon is mandatory to avoid misdiagnosing hematic effusion or urinary-peritoneal fistula.

[Prospective evaluation of the role of abdominal echocardiography in the treatment of seriously traumatized patients]

The reliability of abdominal ultrasonography (US) in a clinical algorithm for emergency management of blunt trauma was evaluated prospectively. From November 1, 1987 to December 31, 1988, of 111 severe trauma victims admitted to our ICU, 63 were screened according to protocol by US for peritoneal fluid and splenic and/or hepatic injuries. The mean age was 49.6 years. The mean ISS and APACHE II Score was 26.9 and 13.7 respectively. The sensitivity of US for detection of peritoneal fluid was 95%, specificity 97.6%, positive predictive value 95%, negative predictive value 97.6% with a prevalence of 31.7%. For hepatic and splenic injuries instead the results were not as good as for abdominal fluid. Twelve patients underwent laparotomy and 6 with abdominal injuries were successfully treated nonoperatively with serial US examinations. Overall mortality was 12 (19%). No patients died for delayed or missed diagnosis of abdominal injury.

Distribution of silver-stained interphase nucleolar organizer regions as a parameter to distinguish neoplastic from nonneoplastic reactive cells in human effusions

The distribution of interphasic nucleolar organizer regions (NORs) was studied in cytologic preparations of human serous effusions in order to differentiate malignant cells from nonmalignant reactive cells. The study was carried out on 80 cases of metastatic adenocarcinoma, 10 cases of mesothelioma, 10 reactive pleural effusions and 5 peritoneal washings. Visualization of NORs at the light microscopic level was obtained using a silver-staining technique for acidic proteins selectively associated with NORs. The morphologic data were also statistically evaluated by means of an automated image analyzer. The quantity of silver-stained NORs was higher in cancer cells (both mesothelioma and adenocarcinoma) than in reactive mesothelial cells. Moreover, NORs were more irregularly distributed within the nucleoli and were more variably sized in cancer cells than in reactive mesothelial cells.

Evaluation of pleural and peritoneal effusions

Certain diseases cause an increase in the amount of fluid present in the pleural and/or peritoneal cavity (an effusion). Uroperitoneum subsequent to kidney, ureter, bladder, or urethra rupture also can cause an increased amount of fluid in the abdomen. Evaluation of fluid samples often is helpful in identifying the mechanism causing the effusion and, occasionally, results in a specific diagnosis. The TP, TNCC, and general cytologic examination can be performed easily, quickly, and inexpensively in-house. The TP and TNCC are used to classify effusions as transudates, modified transudates, or exudates. Transudates usually are caused by hypoalbuminemia, but also can be caused by leakage of fluid from efferent intestinal lymphatics. Cytology and culture usually are not rewarding in the evaluation of transudates. Modified transudates usually are caused by increased vascular permeability or increased intrahepatic hydrostatic pressure. Cytologic and radiographic examinations often are helpful in evaluating patients with modified transudates, while cultures usually are unrewarding. The exudate class encompasses the inflammatory exudates (septic or nonseptic), neoplastic exudates, and chylous effusions. Inflammatory exudates have a high TP and predominantly contain inflammatory cells. They may be septic or nonseptic. When septic, degeneration neutrophils often, but not always, are found. Cultures often are needed to determine whether sepsis is present, to identify the specific organism, and to determine the best therapy. Neoplastic exudates may contain numerous neoplastic cells. If there is concern that the cells are dysplastic instead of neoplastic, the cytology preparation should be referred to a consultant. Chylous effusions usually contain many small lymphocytes with a variable number of neutrophils and macrophages. In chronic chylous effusions, however, neutrophils and/or macrophages may predominate. Chylous effusions usually are differentiated easily from pseudochylous effusions by cytology. Comparison of fluid and serum triglyceride and cholesterol concentrations can be used to differentiate chylous and pseudochylous effusions when differentiation cannot be accomplished by cytology.