Dan M McKeon

University of Minnesota Medical Center, Fairview, Minneapolis, Minnesota, United States

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Publications (7)21.55 Total impact

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    ABSTRACT: The introduction of liquid-based Papanicolaou (Pap) tests (LBPTs) has reduced the incidence of unsatisfactory Pap tests (UPTs), but little is known about their causes and significance, especially in the case of SurePath LBPTs. All unsatisfactory LBPTs from January 1, 2003 to December 31, 2006 were retrieved. The characteristics of patients, providers, and LBPTs; the reason for UPTs; and any cytologic or histologic follow-up within 24 months were recorded. Negative Pap tests that were evaluated immediately after a UPT served as a control group. Of 243,006 Pap tests (95.5% SurePath LBPTs), 0.23% were unsatisfactory. Scant cellularity was the primary cause of SurePath UPT. Women in this UPT group were older, had more diagnostic Pap tests taken, less frequently were taking contraceptives or were pregnant, and were more likely to be menopausal or posthysterectomy. The 278 women who had UPTs had significantly higher rates of follow-up Pap tests (65.1% vs 22.2%), abnormal Pap tests (5.4% vs 1.4%), biopsies (10% vs 1%), and abnormal biopsies (5% vs 1%) than the 284 women in the control group, including 7 women with cervical intraepithelial neoplasia 1 (CIN-1), 1 woman with CIN-2, 4 women with CIN-3, and 2 women with endometrial hyperplasia. The UPT rates varied little between provider groups (physicians vs nonphysicians and gynecologists vs nongynecologists). The frequency of UPTs in a predominantly SurePath LBPT-screened population was very low and was caused mainly by low cellularity. Similar to conventional Pap smears, unsatisfactory SurePath LBPTs had a higher risk of significant histologic abnormalities on follow-up than negative satisfactory Pap tests and could have benefited from a repeat Pap test or other evaluation, according to current management guidelines.
    Cancer 03/2009; 117(1):15-26. · 5.20 Impact Factor
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    ABSTRACT: Apart from several subjective criteria, ASCUS and LSIL are defined by nuclear enlargement of 2.5x to 3x and > or = 3x the area of a normal intermediate squamous cell nucleus, respectively. The aim of this study was to assess the ability of observers with various degrees of experience to estimate nuclear area ratios. Forty-five participants (5 anatomic pathologists, 5 cytopathologists, 2 cytopathology fellows, 16 pathology residents, 8 cytotechnologists, 6 medical students, and 3 cytopreparatory staff members) judged the area ratios of pairs of squamous cell nuclei imaged at x100 objective magnification. For Test 1 (T1), participants chose between 5 preset area ratios (1.0x to 1.4x, 1.5x to 1.9x, 2.0x to 2.4x, 2.5x to 2.9x, 3.0x to 3.4x) for 15 pairs of cells with ratios falling in the middle of these intervals. One week after T1, an instructional tutorial was given and T1 was repeated in different order of cell pairs as Test 2 (T2). The kappa values for all participants were 0.30 for T1 and 0.39 for T2. Accurate responses were given in 50.5% in T1 and 53.5% in T2. Both T1 and T2 responses failed to differentiate between area ratios corresponding to ASCUS and LSIL. There were no differences in accuracy according to sex, experience, or expertise in cytopathology. The overall accuracy of participants in estimating nuclear area ratios was low, especially for ratios in the range of ASCUS versus LSIL, with only minimal improvement after an instructional tutorial. Nuclear area ratio estimation may, therefore, contribute to the well-known substantial variability in ASCUS rates and ASC/squamous intraepithelial lesion ratios.
    Cancer 10/2008; 114(5):287-93. · 5.20 Impact Factor
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    ABSTRACT: The Bethesda 2001 (B2001) classification system raised the threshold for reporting atypical squamous cells. The category of Atypical Squamous Cells of Undetermined Significance (ASCUS)-favor reactive has been eliminated with a recommendation for cytologists to judiciously downgrade those Papanicolaou (Pap) tests that would formerly have been in this category to Negative for Intraepithelial Lesion or Malignancy (NILM). The effect of this change on sensitivity and specificity of the Pap test is not yet known. A total of 535 consecutive SurePath Pap tests interpreted as ASCUS during a period from March 1 through December 31, 2001, with follow-up polymerase chain reaction(PCR)-based human papilloma virus (HPV) testing, were independently reviewed by 3 pathologists and 1 cytotechnologist who reinterpreted these tests according to Bethesda 2001 criteria. Follow-up HPV and biopsy results were compiled for a 5-year period. By consensus of the 4 observers, 169 (32%) of the ASCUS cases were downgraded to NILM. These cases showed a lower rate of underlying high-risk HPV infection (11% vs 30%) and cervical intraepithelial neoplasia of grades 2 to 3 (CIN 2/3) (5% vs 10%) on follow-up than those tests that were reinterpreted as ASCUS or higher. Nine women with follow-up CIN 2/3 would have had the Pap test interpreted as NILM instead of ASCUS under Bethesda 2001 (20% of all CIN 2/3 found). Individual reviewers downgraded 29% to 42% Pap tests to NILM including those of 5 to 10 women with follow-up CIN 2/3. The ASCUS threshold established by B2001 prevents a sizeable subset of women from having follow-up for ASC. However, as a consequence, a few women with CIN 2/3 are downgraded to NILM. The cost savings thus achieved must be weighed against the lost opportunities to detect CIN 2/3.
    Cancer 07/2008; 114(3):171-9. · 5.20 Impact Factor
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    ABSTRACT: Thymic carcinoid tumors (well-differentiated neuroendocrine carcinomas) are uncommon anterior mediastinal neoplasms. These tumors are frequently accompanied by other endocrinopathies as part of a multiple endocrine neoplasia type I syndrome (MEN type I) and by paraneoplastic Cushing's syndrome and have a poor prognosis. We present the case of a 24-year-old man who presented for follow-up of thymic carcinoid with extensive bony metastases. He had recently completed radiotherapy to lesions involving his skull and mandible. An ultrasound-guided left-sided diagnostic and therapeutic thoracentesis was performed yielding 1 l of cloudy yellow fluid. The cytologic fluid preparations consisted of large "cannonballs" and atypical cell groups with salt and pepper nuclear chromatin. A panel of immunohistochemical stains were performed on the cell block material, and the atypical cells were positive for cytokeratin, synaptophysin, and chromogranin, but not for TTF1. These findings were consistent with metastatic well-differentiated neuroendocrine carcinoma (carcinoid tumor). This is the first reported case of a carcinoid tumor manifesting as large, spherical, smoothly contoured cell aggregates ("cannonballs") in a pleural fluid. Despite its rarity, a metastatic carcinoid tumor should be considered when "cannonballs" are found in effusions.
    Diagnostic Cytopathology 06/2008; 36(5):333-7. · 1.49 Impact Factor
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    ABSTRACT: A review of our institution's Papanicolaou test records over an 11-yr period showed that liquid-based Papanicolaou tests (LBPTs) had a significantly higher frequency of diagnoses of Herpes simplex virus (HSV)-related cellular changes compared to conventional Papanicolaou smears (77/302,841, 0.026% vs. 56/376,173, 0.015%, P = 0.002). To investigate the accuracy of the diagnosis of HSV by LBPT, we performed conventional polymerase chain reaction (PCR) on the residual samples from 258 prospectively collected LBPT and real-time PCR using a different primer set on a subset of 40 LBPT. Conventional PCR was positive in 22 of 22 cases diagnosed of HSV, 1 of 2 cases diagnosed as suspicious for HSV, and none of 234 LBPT without a cytologic HSV diagnosis. Real-time PCR was positive in 8 of 8 cases diagnosed as HSV and none of the 32 controls. We conclude that LBPT allows an increased detection of HSV that is highly accurate.
    Diagnostic Cytopathology 03/2008; 36(2):94-103. · 1.49 Impact Factor
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    ABSTRACT: We investigated the morphological features of Trichomonas vaginalis in liquid-based Papanicolaou (Pap) (LBP) tests, in order to assess the impact of this new slide preparation system on recognition of T. vaginalis organisms. We reviewed 88 LBP test slides previously interpreted as showing T. vaginalis and assessed morphological characteristics of the organisms and the presence of secondary features. Eighty-six of 88 slides showed, at least focally, organisms with cytoplasmic granules, nuclei, and flagella allowing for confident recognition of T. vaginalis. Compared with 58 controls, cases of T. vaginalis were more likely to have squamous cells with perinuclear halos, "ghost cells," and coccobacilli. The lack of a "dirty" background or cytolysis allowed a more straightforward identification of the organisms. We concluded that T. vaginalis organisms are morphologically distinct in LBP tests, which may lead to an increased specificity when they are identified in such tests.
    Diagnostic Cytopathology 06/2005; 32(5):253-9. · 1.49 Impact Factor
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    ABSTRACT: Papanicolaou (Pap) test discrepancy rates between cytotechnologists (CTs) and cytopathologists (CPs) are often kept to evaluate the performance of individual CTs. This is based on the unproven assumption that the CP's diagnoses are more likely to be correct. We investigated this assumption using data from our discrepancy files and comparing them to follow-up histology. All Pap test discrepancies were noted between January 1, 2001-December 31, 2001. Surgical pathology files were then searched for follow-up histology within 9 mo of the Pap test. Histologic diagnoses were compared with the previous CT and CP diagnoses, and then judged regarding accuracy. In total, 63,376 Pap tests were evaluated between January 1, 2001-December 31, 2001. There were 795 discrepancies throughout this period (1.25%). One hundred and sixty-six cases with discrepancies had follow-up histology within 9 mo of the Pap test (20.9%). Of downgraded cases (103), CPs were more correct in 51 cases (49.5%), whereas CTs were more correct in 52 cases (50.5%). Of upgraded cases (63), CPs were more correct in 19 cases (30.2%), whereas CTs were more correct in 44 cases (69.8%). Our results suggest that CPs are not more likely to be correct than CTs when there is a discrepancy with the diagnosis of a Pap test, especially when CPs upgrade CT diagnoses. This suggests that discrepancy data may be helpful for evaluating the performance of both CPs and CTs. It may also be of educational use for both CPs and CTs to know the follow-up histology in these cases.
    Diagnostic Cytopathology 09/2003; 29(2):111-5. · 1.49 Impact Factor

Publication Stats

25 Citations
21.55 Total Impact Points

Top Journals

Institutions

  • 2005–2009
    • University of Minnesota Medical Center, Fairview
      Minneapolis, Minnesota, United States
  • 2003–2009
    • University of Minnesota Twin Cities
      • Department of Laboratory Medicine and Pathology
      Minneapolis, MN, United States