Comparison of ThinPrep and conventional preparations on fine needle aspiration cytology material

OBJECTIVE: To compare the various cytologic features on ThinPrep 2000 (TP) (Cytyc Corporation, Marlborough, Massachusetts, U.S.A.) and conventional preparation (CP) specimens from fine needle aspiration cytology (FNAC) material by a semiquantitative scoring system. STUDY DESIGN: In this prospective study a total of 71 consecutive cases were included. In each case, two passes were performed. The first pass was used for conventional preparations, with direct smears made and fixed immediately in 95% alcohol for Papanicolaou stain. For TP preparation a second pass produced material for processing in the ThinPrep 2000. The TP and CP slides were studied independently by two observers and representative slides of CP and TP compared for cellularity, background blood and necrotic cell debris, cell architecture, informative background, presence of monolayer cells, and nuclear and cytoplasmic details by a semiquantitative scoring system. Statistical analysis was performed by Wilcoxon's signed rank test on an SPSS program (Chicago, Illinois, U.S.A.). RESULTS: TP preparations contained adequate diagnostic cells in all cases and were tangibly superior to CP preparations concerning monolayer cells, absence of blood and necrosis, and preservation of nuclear and cytoplasmic detail (statistically significant, Wilcoxon's signed rank test, P < .000). CONCLUSION: TP preparations are superior to conventional preparations with regard to clear background, monolayer cell preparation and cell preservation. It is easier and less time consuming to screen and interpret TP preparations because the cells are limited to smaller areas on clear backgrounds, with excellent cellular preservation. However, TP preparations are more expensive than CP and require some experience for interpretation.     

Diagnosis of metastatic tumors in cerebrospinal fluid samples using thin-layer cytology

OBJECTIVE: To evaluate the application of ThinPrep liquid-based cytology (LBC) and present our experience using LBC in the diagnosis of metastatic tumors in cerebrospinal fluid (CSF) samples. STUDY DESIGN: We examined 38 cytologic specimens of CSF, processed by ThinPrep technique. Of these, 18 presented with a previously diagnosed primary malignancy. Various immunocytochemical markers were performed. RESULTS: ThinPrep technology provided preservation of cytomorphologic features, high cellularity per slide and clear background. Analysis revealed 8 breast carcinomas, 5 lung carcinomas, 4 lymphomas, 3 adenocarcinomas of the gastrointestinal tract, 1 squamous cell carcinoma of uterine cervix and 1 urinary bladder carcinoma. Fifteen samples were negative for malignancy. CONCLUSION: CSF cytology is the only examination that verifies the presence of malignancy. Thin monolayer technology is suggested as an appropriate diagnostic method for metastatic tumors in CSF in everyday routine and seems to be a valuable tool for further management and planning of treatment.     

Liquid-based vs. conventional smears in fine needle aspiration of bone and soft tissue tumors

OBJECTIVE: To compare the accuracy of fine needle aspiration cytology of bone and soft tissue tumors utilizing ThinPrep (TP) (Cytyc Corporation, Boxborough, Massachusetts, U.S.A.) vs. conventional smears (CS). STUDY DESIGN: Fine needle aspiration cytology from bone and soft tissue tumors was processed and assessed for cellularity, nuclear and cytoplasmic preservation, cellular architecture and stromal background with both the TP liquid-based smear technique and conventional methods. RESULTS: An accurate diagnosis was made in 13% of TP cases as compared to 64% in CS cases. CONCLUSION: CS of fine needle aspiration sample is far superior to TP in diagnosing tumors of bone and soft tissues. Preservation of cytoplasmic features and cellular architecture was superior in conventionally prepared smears.     

Evaluation of thin-layer methods in urine cytology

Conventional cytospin smears prepared from urinary tract specimens were compared with two new thin layer techniques, i.e. ThinPrep and AutoCyte PREP. Cellularity, cell preservation, background features, detection rate, screening time and ease of preparation were evaluated. Thin-layer techniques when applied to urine cytology were found to improve cell yield and cell preservation, and reduce background artefact. The reporting rate for abnormal urothelial cells was comparable to conventional cytospin smears, as was screening time. Laboratory staff found the methodologies to be practicable and easily incorporated into a large routine diagnostic service. We conclude that a one-slide thin-layer urine preparation is comparable to four cytospin slides in the detection of urothelial abnormalities, and that both ThinPrep and AutoCyte PREP have comparable features.     

Efficacy of fine needle capillary sampling in the diagnosis of stage III and IV cervical carcinoma

OBJECTIVE: To test the sensitivity of fine needle capillary sampling (FNCS) as compared to scrape cytology in cervical carcinoma, stage III and IV, and to study the quality of material obtained by FNCS. STUDY DESIGN: Prospective. In 48 cases of cervical carcinoma, clinically stage III and IV, FNCS was done along with scrape cytology. The results were compared, considering histopathology as the gold standard. The quality of material obtained by both methods was compared using the parameters background, cellularity and cellular preservation. RESULTS: FNCS had a sensitivity of 87.5% as against 62.5% for scrape cytology. Material obtained by FNCS had a cleaner background and better cellularity and morphologic preservation. CONCLUSION: FNCS is superior to scrape cytology for the diagnosis of stage III and IV cervical carcinoma.     

Liquid-based cytology findings of glassy cell carcinoma of the cervix. Report of a case with histologic correlation and molecular analysis

BACKGROUND: Glassy cell carcinoma is a rare form of poorly differentiated carcinoma of the cervix with no obvious squamous or glandular differentiation. Its liquid-based cytology findings have not been described before. CASE: A 46-year-old Filipina presented with vaginal bleeding due to a bulky cervical tumor. The liquid-based cytology preparation was of moderate cellularity and contained small clusters of polygonal to elongated tumor cells admixed with amphophilic, granular, necrotic debris. The malignant cells possessed round to oval nuclei; a thin nuclear membrane; finely dispersed chromatin; prominent, solitary nucleoli; abundant, cyanophilic cytoplasm; and discrete cell borders. Occasional tumor cells showed phagocytosis of polymorphs. The background contained a mixed population of inflammatory cells. Eosinophils, though present, were not readily identified in the cytologic specimen. There was no evidence of dyskeratosis, cytoplasmic vacuolation or koilocytosis. Histologic and ultrastructural examination of the tumor biopsy showed classic features of glassy cell carcinoma. Molecular analysis using polymerase chain reaction and restriction fragment length polymorphism revealed the presence of human papillomavirus (HPV) DNA in the liquid-based cytology sample. The HPV genotype, however, did not belong to any of the commonly encountered prototypes. CONCLUSION: Glassy cell carcinoma of the cervix may show distinct, though subtle, cytomorphologic features in liquid-based preparations. The findings, however, are slightly different from those in conventional cervical smears. Awareness of this rare entity is important, as glassy cell carcinoma is often associated with more aggressive clinical behavior.     

Cell blocks from scraping of cytology smear: comparison with conventional cell block

OBJECTIVE: To compare cytomorphology preservation and immunohistochemistry results between conventional cell blocks (CCB) and cytoscrape cell blocks (SCB). STUDY DESIGN: Fine needle aspiration (FNAC) was done in 17 consecutive cases. Air-dried smears for May-Grünwald-Giemsa stain and wet-fixed smear for hematoxylin-eosin (H-E) stain were prepared. Simultaneously another pass was made in each case for preparation of material for CCB. One of the H-E-stained smears was spared for SCB. SCB was compared with CCB for cell morphology. Immunostaining was performed both cell blocks, as well as on FNA smears in 8 cases. Results were evaluated for intensity of staining and percentage of cells showing positivity. RESULTS: CCB and SCB sections showed adequate cellularity in all cases. Morphologic preservation was good in SCB sections. There was good architectural and nuclear preservation in all cases of SCB. Immunostaining results showed better and clear intensity of staining with little background in all cell block cases. CONCLUSION: SCB is a valuable technique in cell blocks from stained FNA smears. The cytomorphologic details are equally good in SCB and CCB. Additional panels of immunostaining can be done on SCB for better diagnosis and classification, particularly in cases in which repeat FNA is not possible.     

Comparison of conventional Papanicolaou smear and SurePath® liquid-based cytology in the Copenhagen population screening programme for cervical cancer

OBJECTIVE: To compare diagnostic performance of conventional Papanicolaou smear with SurePath liquid-based cytology in a population screening programme. METHODS: A retrospective comparison was performed on data from two 18-month periods of the screening programme for cervical cancer in the municipality of Copenhagen with conventional Papanicolaou technique (n = 82,116) and liquid-based cytology (n = 84,414). RESULTS: After the conversion to liquid-based cytology the percentage of unsatisfactory samples decreased from 2.3% to 0.3% (P < 0.001), whereas the number of normal cervical samples lacking an endocervical component increased from 8.5% to 8.9% (P < 0.005). The percentage of samples with atypical cells and cells suspicious for malignancy increased from 3% to 4.2% (P < 0.001) and from 1.9% to 2.4% (P < 0.001), respectively. The subsequent histological follow-up showed normal findings decreased from 70.5% to 68.9% and from 28.0% to 26.1%, respectively. However, in relation to the entire screening populations, there was an increase of normal findings from 2.12% to 2.89% after primary atypical diagnosis and from 0.53% to 0.62% after diagnosis of suspicious cells after conversion to the liquid-based technique. CONCLUSIONS: This study showed the number of unsatisfactory samples to be significantly reduced with the liquid-based technique. The data suggest that there is an increased detection rate of cervical precancerous lesions with liquid-based cytology, but the number of false positive tests is still high. The specificity of the two tests seems similar, but this cannot be ascertained exactly, because of the fact that follow-up of negative cases is unavailable.     

Performance of monolayered cervical smears in a gynecology outpatient setting in Kuwait

OBJECTIVE: To compare ThinPrep (TP) Papanicolaou smears (Cytyc Corp., Box-borough, Massachusetts, U.S.A.) with matching conventional Papanicolaou (CP) smears for specimen adequacy, cytologic quality, diagnostic accuracy and screening time. STUDY DESIGN: In this prospective study of 1,024 women a split-sample, matched-pair design in favor of CP slides based on single-blind criteria was followed with a smear on a glass slide for CP and the remaining material collected in Preserv-Cyt solution (Cytyc) for a TP smear. A Cytobrush (Medscand, Hollywood, Florida, U.S.A.) was used for smear preparation for CP. TP smears were processed in ThinPrep 2000 (Cytyc). Smears were stained with Papanicolaou stain and were interpreted according to the Bethesda system. RESULTS: The number of satisfactory but limited (SBL) cases with TP were 77 (7.5%) as compared to 127 (12.4%) with the CP method. This reduction in SBL smears with the TP method and consequent increase in satisfactory smears were highly significant (P < .001) by McNemar's test. As regards unsatisfactory smears in discordant pairs, although the number of unsatisfactory smears was higher with TP (41 cases) as against CP (27 cases), the difference was not statistically significant (P < .05). The split-sample method showed a high correlation between the CP and TP diagnoses. TP smears had a significant advantage over CP smears in the reduction in the number of ASCUS and AGUS cases (14 vs. 29) (P < .05) and increased the pickup rate of LSIL, 6 vs. 1. Time taken to screen the TP smears was half that of CP smears. No cases of LSIL or HSIL were missed on TP smears. CONCLUSION: The liquid-based processor significantly improved the adequacy and quality of smears, resulting in fewer recall cases for SBL smears, leading to more definitive diagnoses in atypical cases, increasing the pickup rate of LSILs and reducing the screening time. A machine handling multiple specimens automatically would decrease cost and be an asset to a cytopathology laboratory.     

New red blood cell lysing fixative for use in fine needle aspiration and fluid cytology

OBJECTIVE: To describe a new red blood cell (RBC) lysing fixative, Devine's lysing solution (DLS), that increases the diagnostic utility of fine needle aspiration (FNA) and fluid cytology. STUDY DESIGN: Twenty bloody FNA cases were fixed with either DLS or 95% ethanol, and the ability to render a diagnosis on these materials was analyzed. DLS was compared to the red cell lysing fixative CytoRich Red (CRR) (TriPath Care Technologies, Burlington, North Carolina, U.S.A.) in its ability to lyse RBCs by mixing human RBCs with the U266 multiple myeloma cell line. DLS was compared to CRR in its ability to suitably preserve materials for Papanicolaou and immunocytochemical analysis. RESULTS: Comparison of DLS with 95% ethanol fixation in 20 bloody FNA cases prepared in duplicate showed that DLS reduced from 17 to 3 the number of cases that had RBCs obscuring > or = 25% of the diagnostic material. In 3 cases, DLS enabled the rendering of a definitive diagnosis of malignancy, which could not be made on the ethanol-fixed material. DLS was compared to CRR, and both fixatives were similarly effective at lysing RBCs, preserving the cellular morphology of diagnostic cells in FNA and fluid cytology, and preserving cells for use in immunocytochemistry. CONCLUSIONS: DLS increases the visualization of diagnostic cellular material when compared to ethanol fixation. DLS is comparable to CRR in RBC lysing ability, diagnostic cell preservation and preservation of materials for immunocytochemistry.     

Enhancing recovery of endocervical component on gynecologic cytology specimens processed by thin-layer technology

OBJECTIVE: To address the causes and report the corrective measures required for resolving the initial problem of high rates of cervical vaginal cytology specimens reported as having no endocervical component on SurePath (AutoCyte, Inc., Burlington, North Carolina, U.S.A.) liquid-based, thin-layer technology at an academic center cytology laboratory. STUDY DESIGN: Analysis of 511 cases lacking endocervical/transformation zone component out of 9,221 SurePath thin-layer gynecologic specimens processed in a one-year period. The study encompassed a review of sample collection techniques by physicians and nurses, specimen processing, cytologic features of endocervical/squamous metaplastic cells processed by the SurePath method and statistical analysis of endocervical cell recovery rates after implementation of corrective measures. RESULTS: Absence of endocervical/transformation zone component varied from an initial 18% in the first month to an average of 5.3% after corrective actions were implemented. Current rates of SurePath thin-layer specimens having no endocervical component are lower than those for conventional smears. CONCLUSION: Since SurePath was only recently introduced to the market, there are no previously published data addressing how to optimize the recovery of endocervical component on liquid-based, thin-layer specimens processed by this methodology.     

Processing liquid-based gynecologic specimens: comparison of the available techniques.

OBJECTIVE: To develop a cytopreparation protocol suitable for satisfactory processing by the AutoCyte PREP System with the gynecologic specimens collected in PreservCyt fluid for the ThinPrep machine. STUDY DESIGN: The residue of a number of gynecologic specimens collected in PreservCyt and processed by ThinPrep were processed by AutoCyte PREP. Some modifications were made in the cytopreparatory protocol in order to obtain satisfactory specimens. RESULTS: The ThinPrep and AutoCyte PREP specimens were examined independently. The results were comparable, with a high degree of concordance between the two techniques. CONCLUSION: Gynecologic specimens collected in PreservCyt and following the ThinPrep specimen collection protocol can be processed using the AutoCyte PREP System. Minor protocol modifications provided comparable diagnostic material. Additional studies are needed to explore the feasibility of this approach and fulfill the various U.S. regulatory agency requirements for the liquid-based Pap test.     

Cytologic diagnosis of pulmonary nocardiosis: a report of 3 cases

BACKGROUND: Nocardiosis is an uncommon infection and presents as an opportunistic infection in an immunocompromised host. Pulmonary infection by Nocardia may be difficult to diagnose based on clinical and radiologic features, as these are not specific. Sputum examination, bronchoalveolar lavage and transthoracic ultrasound/computed tomography-guided fine needle aspiration cytology offer a simple means of procuring material for diagnostic evaluation. Very few articles have described the morphologic appearance of this uncommon pathogen in cytologic material. CASES: Three cases occurred in patients with an underlying immunocompromised state. Patient 1 was on steroid therapy for nephrotic syndrome, patient 2 was on immunosuppressant therapy after renal transplantation, and patient 3 was HIV positive. A diagnosis of pulmonary nocardiosis was suspected on Papanicolaou stain. Modified Ziehl-Neelsen stain and silver methanamine stains were useful in confirming the diagnosis. CONCLUSION: A high index of suspicion for nocardiosis must be maintained while assessing cytologic material in immunosuppressed individuals as it may be masked by the intense inflammatory exudate associated with this infection. A meticulous search may reveal the presence of delicate, thin, faintly stained, branching filaments of Nocardia on routine Papanicolaou stain. Special stains and culture studies are useful in confirming the diagnosis.     

Cytodiagnosis of eumycotic mycetoma: a case report

BACKGROUND: Mycetoma is a late-stage clinical manifestation of a subcutaneous infection produced by bacteria (actinomycetoma) or fungi (eumycetoma). Only a few articles have described the morphologic appearance of this uncommon pathology on cytology. The distinction between eumycetoma and actinomycetoma in fine needle aspiration cytology (FNAC) is as accurate as in histopathology, as demonstrated in the present case. CASE: A 30-year-old man presented with a large swelling on his left foot with a discharging sinus. FNAC of the swelling yielded pus-like material. Initial Papanicolaou and Giemsa stains showed the presence of septate, branching fungal hyphae and black granules against the inflammatory background. The presence of fungus was confirmed by PAS stain. The species was identified as Exophiala jeanselmei on fungal culture. CONCLUSION: Mycotic mycetoma can be accurately diagnosed by FNAC, which is a simple, inexpensive and rapid technique when there is a high index of suspicion. Special stains and culture studies are helpful in confirmation of diagnosis and species identification.     

Salivary gland fine needle aspiration using the ThinPrep technique: diagnostic accuracy, cytologic artifacts and pitfalls

OBJECTIVE: To retrospectively assess the diagnostic accuracy, cytologic features and pitfalls of ThinPrep (TP) (Cytyc Corporation, Marlborough, Massachusetts, U.S.A.) versus conventional (smear) preparation (CP) in salivary gland fine needle aspiration biopsies (FNABs) and second, to evaluate the reproducibility of the cytomorphologic criteria used in the evaluation of FNABs prepared by CP versus TP. STUDY DESIGN: All salivary gland fine needle aspiration biopsies (SGFNABs) between January 1996 and June 1999 were retrieved from the cytology files of the University of Michigan Hospital. Histologic correlation was identified when available. Two cytopathologists reevaluated the slides for artifacts, cellular preservation, background material, cellularity, and cytoplasmic and nuclear details. RESULTS: Seventy-four of the 134 (55%) cases identified had histologic follow-up. Fifty (68%) cases were processed by TP and 24 (32%) by CP. FNAB processed by TP and CP correctly identified malignancy in 14 and 9 cases, respectively. There were three (4%) false negative cases. These included two acinic cell carcinomas and one mucoepidermoid carcinoma. There were 37 true negative cases (24 TP and 13 CP) and one false positive case of cellular pleomorphic adenoma (cytologic interpretation, mucoepidermoid carcinoma). All discrepant cases were processed using the TP method. The overall specificity and sensitivity were 98% and 88%, respectively. However, specificity and sensitivity for TP-processed SGFNABs were 96% and 82% as compared to a 100% specificity and sensitivity for CP. Additionally, there were 10 (14%) nondiagnostic cases, 8 of which were processed by TP. Cytologic artifacts associated with TP included diminished/distorted extracellular and stromal elements, cellular shrinkage and tissue fragmentation CONCLUSION: The diagnostic accuracy of TP-processed SGFNABs approaches that of the CP. However, there are several artifacts that may lead to erroneous diagnoses. Additional studies, that depend on real-life clinical samples processed by TP are suggested to modify current diagnostic criteria.     

Skin imprint cytology in the diagnosis of cutaneous T-cell lymphomas. A preliminary report

A study was undertaken to evaluate the utility of the skin imprint technique and the Papanicolaou stain in the diagnosis of cutaneous T-cell lymphomas (CTCL), to better characterize cytologic findings in CTCL and to establish criteria for the cytologic diagnosis of CTCL. Differential cell counts of 17 specimens, including 12 cases of CTCL and 5 of benign skin infiltrates, were performed. There appear to be some significant differences between the groups in terms of cellularity, number of cerebriform mononuclear cells and presence of mitotic figures. The skin imprint technique, using Papanicolaou staining, seems to facilitate recognition of diagnostically important cells. The usefulness of skin imprint cytology resides in its potential for diagnosing early lesions of CTCL when diagnosis by other methods may be difficult.     

A comparison of variability in Papanicolaou and liquid-based cytology inadequacy rates using Shewhart control charts

OBJECTIVE: To use Shewhart control charts to compare variability in inadequacy rates from Papanicolaou (Pap) and liquid-based cytology (LBC). DESIGN: Retrospective analysis of quality assurance data. SETTING: Eleven Welsh cytology laboratories. METHODS: Shewhart 'p' charts were plotted for proportions of slides reported as inadequate. Charts were compared for statistical control. MAIN OUTCOME MEASURES: Evidence of statistical control in the processes. RESULTS: Control charts allowed easy interpretation of patterns in the data. Variability in inadequacy rates was much lower for LBC than for Pap cytology. CONCLUSION: Monitoring inadequate rates with Shewhart charts provides more information than tabular monitoring reports, assisting in quality improvement. With respect to inadequacy rates, LBC is less variable than Pap cytology.     

Determination of liquid-based cervical cytology specimen adequacy using cellular light scatter and flow cytometry.

BACKGROUND: The majority of cervical cytology specimens are being collected in liquid-based preservatives (LBP). However, the assessment of specimen adequacy, as mandated by The Bethesda System (TBS), is still being performed at the time of slide review. We present a rapid, flow cytometric method for assessing specimen adequacy. METHODS: Three LBPs were compared for cell-surface antigen preservation. A three-color antibody panel was used to confirm the light scatter profile of specific cells in a liquid-based cervical cytology specimen. Using forward and orthogonal light scatter alone, we were able to assess the adequacy of liquid-based cytology specimens in all LBPs tested. RESULTS: The number of polymorphonuclear neutrophils (PMNs), endocervical (columnar) cells, ectocervical (squamous) cells, and debris in 120 liquid-based cervical cytology samples was quantified in less than 10 min. Using cutoffs of > 20% PMNs, < 1.0% endocervical cells, < 1.0% ectocervical cells, and < 500 total cells per milliliter, light scatter correlated with microscopic determination of adequacy with a correlation coefficient of 0.99. CONCLUSIONS: This rapid method allows the quantitative determination of cervical cytology adequacy in liquid-based cytology preparations prior to the preparation of slides for morphologic assessment.     

Papanicolaou stain: Is it economical to switch to rapid, economical, acetic acid, papanicolaou stain?

OBJECTIVE: To standardize an inexpensive and rapid Papanicolaou staining technique with limited ethanol usage. STUDY DESIGN: Smears from 200 patients were collected (2 per patient) and fixed in methanol. Half were subjected to conventional Papanicolaou and half to stain ing with rapid, economical, acetic acid Papanicolaou (REAP) stain. In REAP, pre-OG6 and post-OG6 and post-EA36 ethanol baths were replaced by 1% acetic acid and Scott's tap water with tap water. Hematoxylin was preheated to 60 degrees C. Final dehydration was with methanol. REAP smears were compared with Papanicolaou smears for optimal cytoplasmic and nuclear staining, stain preservation, cost and turnaround time. RESULTS: With the REAP method, cytoplasmic and nuclear staining was optimal in 181 and 192 cases, respectively. The staining time was considerably reduced, to 3 minutes, and the cost per smear was reduced to one fourth. The staining quality remained good in all the smears for > 2 years. CONCLUSION: REAP is a rapid, cost-effective alternative to Papanicolaou stain. Though low stain penetration in large cell clusters is a limitation, final interpretation was not compromised.     

Fine needle aspiration of pancreatic cystic epithelial neoplasms.

Pancreatic cystic epithelial neoplasms present diagnostic challenges in cytology. An accurate diagnosis is important since the prognosis and treatment may vary. We report the cytologic features in fine needle aspirates of four cases of cystic neoplasms of the pancreas (two micro-cystic adenomas, one mucinous cystic neoplasm and one mucinous cystadenocarcinoma). Smears were evaluated as to their cellularity, content and predominant cell type. Aspirates from the microcystic adenomas yielded hypocellular material with rare strips of cuboidal cells having bland nuclei and pale cytoplasm. No mucinous material was identified in the background, but the cells stained positively with periodic acid-Schiff stain. Smears from the mucinous cystic neoplasm were moderately cellular and contained abundant mucinous material. The columnar epithelial cells were arranged in tight sheets, clusters and strips. Most cells had benign nuclear features with focal mild nuclear atypia. Key cytologic findings noted in the mucinous cystadenocarcinoma were moderate cellularity, loose clusters of cells, single cells, overt malignant nuclear features and occasional signet ring cells. Pancreatic pseudocysts can be distinguished from pancreatic cystic epithelial neoplasms by the predominance of histiocytes and inflammatory cells and absence or paucity of epithelial cells. To differentiate microcystic adenomas from mucinous cystic neoplasms, the above criteria coupled with periodic acid-Schiff and mucin staining should effectively differentiate these diagnostic entities.