Faculty Bibliography

Simian Virus 40 (SV 40) was recently implicated in the pathogenesis of malignant mesothelioma. The oncogenic capacity of SV-40 is a function of a nuclear protein, the large T antigen (Tag). SV-40 Tag DNA sequences are detected by the polymerase chain reaction in 40-80% of malignant mesothelial proliferations. However, the role of immunohistochemistry (IHC) in demonstrating the nuclear localization of Tag is controversial. We sought to determine the clinical utility of SV-40 Tag IHC in pleural effusion cytology as an ancillary tool in the cytologic diagnosis of malignant mesothelioma (MM). Formalin-fixed, paraffin-embedded cell block sections from 100 pleural effusions (32 MMs, 25 benign reactive, 43 metastatic adenocarcinomas) were immunostained for the SV-40 anti-Tag, using two primary monoclonal SV-40 Tag antibodies: clone Pab 416 and clone Pab 101. Despite strong and consistent immunoreactivity in positive controls, no nuclear immunostaining was observed in any case. We believe the small sample size in cytology cell block sections, the low viral copy number in infected cells, and the effect of formalin fixation may have resulted in absence of immunoreactivity. The role of SV-40 Tag IHC in diagnostic cytopathology remains unclear unless further studies reliably show its detection

Tubular adenocarcinoma is an invasive mammary adenocarcinoma associated with an excellent prognosis and a low incidence of axillary metastases. However, identification of tubular adenocarcinoma by fine-needle aspiration (FNA) biopsy has proven difficult. One hundred five patients with documented 'pure' tubular adenocarcinoma were diagnosed at Tisch Hospital from August of 1992 to December of 1998. Twenty-one of these patients had an FNA before excision. We reviewed the smears of these cases and compared them with cases of fibroadenoma and fibrocystic change to identify criteria for diagnosis. Moderately to highly cellular smears with angular cellular clusters with sharp borders and oval cells outlining these clusters, dispersed single cells with minimal atypia, and the absence or paucity of dispersed bare oval nuclei in the background were features that suggest a diagnosis of tubular adenocarcinoma in our study. Attention to these features in combination with appropriate mammographic findings should preclude a false-negative diagnosis in the majority of cases of tubular adenocarcinoma diagnosed by aspiration biopsy. We point to the presence of the peripheral perpendicular cells in the characteristic tubular arrays as an important clue to the diagnosis of tubular adenocarcinoma

Fibroadenoma (FA) is a common benign breast lesion frequently sampled by fine-needle aspiration biopsy (FNAB). Although the cytologic diagnosis is straightforward in most cases, cellular discohesion and atypia in FAs may lead to falsely atypical or positive FNAB diagnoses. Conversely, some adenocarcinomas mimic a fibroadenomatous pattern on FNAB, resulting in a false-negative diagnosis. We reviewed the cytologic and histologic findings in 25 cases with a preoperative FNAB diagnosis of FA, wherein excision was recommended based on atypia. Our aim was to analyze the spectrum of changes causing under- or overdiagnosis in such cases. The smears were assessed for cellularity, cellular discohesion, presence of dissociated intact cells and nucleoli, nuclear pleomorphism, oval bare nuclei, and stromal fragments. The histologic findings were correlated with FNAB features. At excision, 88% of FAs classified as atypical on FNAB were benign (FA with ductal hyperplasia and lactational change, myxoid FA, and other fibroepithelial lesions). Differentiating myxoid FA from colloid carcinoma was difficult due to the abundance of extracellular mucin in which the dissociated epithelial cells were floating. Two (8%) cases were carcinomas on excision; the reasons for underdiagnosis in one case reflected sampling, and in the other, interpretative error. There was one (4%) benign phyllodes tumor which lacked stromal fragments and single stromal cells on FNAB smears. The lesion was called atypical, based on the epithelial discohesion on the smears. We conclude that the majority of FAs with atypia on FNAB are benign lesions. Considering the grave consequences of a false-positive cytologic diagnosis, we recommend a conservative approach in interpreting FNAB smears which overall display a fibroadenomatous pattern

OBJECTIVE: To evaluate the overall cytologic characteristics of diffuse alveolar damage (DAD) in bronchoalveolar lavage (BAL) specimens in search of features that could be useful in cytologic diagnosis. STUDY DESIGN: We evaluated BAL samples from patients with DAD obtained simultaneously with transbronchial biopsies (n = 8) or open lung biopsies (n = 2) or within 24 hours of autopsy (n = 2). The material was processed routinely for cytologic and histologic evaluation. RESULTS: The smears were moderately to highly cellular. All cases had large numbers of alveolar macrophages and/or desquamated alveolar cells. The epithelial component displayed various degrees of nuclear atypia. Some epithelial clusters were three-dimensional, with peripheral cells showing clear cytoplasm, protruding outwards and resembling hobnails. Other aggregates appeared two-dimensional, as sheets of cells with flattened and dense cytoplasm (squamotized). Both types of cell clusters were often associated with dense, basophilic or amphophilic, amorphous extracellular material. Counterparts of all the cytologic features were observed in the histologic material, including atypia of the alveolar lining with hobnailing, squamotization, amorphous extracellular material and hyaline membranes. CONCLUSION: The cytologic features of BAL represent a constellation of alveolar cell injury. Based on these features, DAD can be correctly diagnosed or suggested in BAL samples in the appropriate clinical setting

Human polyoma virus (PV) interstitial nephritis occurs in immunosuppressed patients after reactivation of latent virus in renal epithelium. Currently, there is neither general consensus about the incidence of clinically significant PV infection in renal transplants nor conclusive evidence determining its significance in the long-term graft outcome. We evaluated 601 renal transplant biopsy specimens (from 365 patients) by routine light microscopy and immunoperoxidase stains with antibody against SV40 (which cross reacts with PV). We also examined urine samples from 200 patients (100 obtained concurrently with a renal biopsy in patients presenting with acute graft dysfunction and 100 from patients with stable graft function). Electron microscopic evaluation was performed in 50 renal biopsy specimens and in 23% of all urine samples. PV was identified in 1.8% biopsy specimens (1.9% of patients). PV interstitial nephritis showed the typical viral cytopathic changes in tubular epithelial cells associated with marked tubular damage and a disproportionately mild degree of tubulitis. There was no difference in the incidence of PV in the urine of patients with acutely deteriorating versus stable renal function (18% and 19%, respectively); however, urines with large numbers of infected cells (> 10/cytospin) and inflammatory changes in the sediments corresponded invariably to patients with acute allograft dysfunction (8 of 8), and in most cases to biopsy specimens showing PV interstitial nephritis (7 of 8). Based on these findings, urine samples seem to be the most sensitive and cost-effective screening method for PV infection; only urine samples with inflamed sediments and abundant infected cells correlate with clinically significant disease. In these cases, examination of a renal biopsy is indicated. Immunohistochemical stains are useful to confirm the presence of PV but do not increase the sensitivity of diagnosis of PV if this is not already suspected on routine light microscopy. In our material, immunostains were helpful ruling out the presence of PV in a small number of biopsy specimens (2%) that showed markedly reactive tubular cells resembling PV infection. Most patients with PV interstitial nephritis responded to decreased immunosuppression; however, the decay in graft function (based on creatinine slopes) was significantly more rapid in these patients than in matched controls. Evidence of PV infection should be systematically sought in renal biopsy specimens and urine samples from renal allograft recipients

Most Non-Hodgkin's lymphomas(NHL) can be accurately diagnosed and classified based on morphologic and immunophenotypic findings on cytologic specimens. Immunophenotyping can be accomplished via immunocytochemistry (IC) or flow cytometry (FC). We reviewed our experience with 98 cytology specimens (70 fine-needle aspirates [FNA] and 28 effusions) that were submitted for immunophenotyping utilizing both IC and FC between January 1992 and December 1997 for the diagnosis of NHL. Eighty-five percent of the cases were immunophenotyped by both techniques. Among these there were only two discrepancies between IC and FC, yielding a 98% correlation rate. Of the 98 cases, 11% could not be immunophenotyped by FC and 4% could not be immunophenotyped by IC. The advantage of IC is the preservation of cytomorphology, which results in the requirement for a lower number of neoplastic cells and a limited, targeted panel of antibodies. This is especially useful in predominantly necrotic lymphomas in which only a few well-preserved neoplastic cells may be present, rendering the specimen inadequate for immunophenotyping by FC. The advantages of FC are in the detection of a small population of monoclonal cells in a background of reactive cells (particularly useful in effusion samples in which the predominant cell population is often reactive T lymphocytes), increased diagnostic precision through evaluation of objective parameters, and the use of multiple markers with dual labelling. We conclude that IC and FC are both excellent methods for immunophenotyping of cytology specimens and can be used interchangeably depending on the institutional expertise and availability

The distinction between reactive mesothelial cells (RMC), malignant mesothelioma (MM), and metastatic adenocarcinoma (ACA) in pleural effusions may be impossible based on morphology alone. E-cadherin, N-cadherin, and calretinin are newly described immunocytochemical markers which can potentially be utilized for facilitating this distinction. E-cadherin and N-cadherin are calcium-dependent intercellular adhesion molecules expressed in epithelial cells and mesenchymal/mesothelial cells, respectively. The differential expression of E-cadherins in epithelial cells and N-cadherins in mesothelial cells has been utilized to differentiate reactive mesothelial cells, MMs and ACAs. Calretinin is a calcium-binding protein within the family of EF-hand proteins. It is abundantly expressed in peripheral and central nervous tissues, and has been shown to consistently immunoreact with mesothelial cells. We studied cell block sections from 77 pleural effusions (22 RMC, 26 MM, and 29 ACA) to investigate the potential immunocytochemical use of anti-E-cadherin, anti-N-cadherin, and anti-calretinin antibodies for differentiating between RMC, MM, and ACA in pleural effusions. A modified avidin-biotin peroxidase complex (ABC) method was used. E-cadherin immunostaining was observed in 14% of RMC, 46% of MMs, and 97% of ACAs. A distinct membrane staining pattern was seen in ACAs. The pattern of staining was cytoplasmic in all reactive RMC and varied from membrane to cytoplasmic in MMs. Anti-N-cadherin immunoreacted with 77% of RMC, 35% of MMs, and 48% of ACAs. Twenty-seven percent of RMC, 58% of MMs, and 31% of ACAs immunoreacted with anti-calretinin. Based on these results, we conclude that anti-E-cadherin is a potentially useful marker in the distinction of ACA cells from RMC. However, it is not as useful for the distinction of ACA and MM. Anti-N-cadherin and anti-calretinin did not reliably distinguish between reactive mesothelial, MM, and ACA cells in pleural effusions

To determine the origin and nature of mucinlike material in fine-needle aspiration (FNA) smears of the breast in noncancerous breast lesions, we studied breast FNA smears from four patients. All smears contained epithelial cells floating in a mucinlike background, which raised suspicion for mucinous (colloid) carcinoma. Mucicarmine stain was performed on one smear from each case. Subsequent tissue biopsy specimens were studied using mucicarmine, periodic acid-Schiff with and without diastase, and alcian blue stains at pH 2.7 and 0.9 on selected tissue sections. Correlation of the cytologic and histologic findings of each lesion was performed. The mucinlike background in all four FNA smears stained strongly with mucicarmine. Corresponding biopsy specimens revealed pseudoangiomatous hyperplasia in the first case, fibroadenoma and atypical ductal hyperplasia in the second, benign phyllodes tumor in the third, and fibroadenoma in the fourth. Each lesion in cases 1 to 3 was associated closely with fibrocystic changes. In case 4, cystic changes were located within the fibroadenoma. On tissue sections of all four cases, the cyst contents and 10% to 50% of normal lobule and duct contents stained with mucicarmine, indicating that the cyst contents were the most probable source of mucin in the FNA smears. The presence of pools of mucicarmine-positive material in FNA smears of the breast is not an exclusive feature of mucinous carcinoma; mucicarmine-positive mucin can arise from benign cystic changes as well as from normal lobules and ducts

Adenovirus (ADV) is increasingly recognized as a cause of morbidity and mortality in transplant recipients, but ADV pneumonitis has rarely been reported after lung transplantation. The few reported instances of ADV pneumonitis occurred mostly in children immediately after lung transplantation suggesting 'primary' infection. We report a fatal case of ADV pneumonitis occurring in an adult, 4 years after unilateral lung transplantation, in whom the premortem diagnosis was not determined. Autopsy revealed severe necrotizing bronchitis, bronchiolitis, and interstitial pneumonitis. Characteristic smudgy intranuclear inclusions, immunohistochemistry for viral protein, in situ hybridization for viral genome, and postmortem lung cultures established ADV as the etiologic agent. ADV can cause fatal, occult respiratory infection in adult lung transplant recipients, remote from transplant surgery

OBJECTIVE: To compare the relative strengths of two factors involved in making an accurate differentiation between functional and epithelial ovarian cysts, along with their combination: (1) the cytologist's level of experience in interpreting ovarian cytology, (2) the use of the tumor markers carcinoembryonic antigen (CEA) and CA-125 in cyst fluid, and (3) a combination of (1) and (2). STUDY DESIGN: Papanicolaou-stained sediments from fluid aspirated from 31 resected ovarian cysts (6 functional and 25 epithelial) were blindly and independently evaluated by five pathologists with varying experience in ovarian cytology. Cyst fluid supernatant was used for CEA, enzyme-linked immunosorbent assay, and CA-125 radioimmunoassay; CEA levels > 5 ng/mL or CA-125 > 5,000 U/mL were considered elevated. Cysts were categorized cytologically and histologically as functional or epithelial and by tumor markers as 'neither elevated' or 'either or both elevated' (EBE). RESULTS: The agreement of histologic diagnosis with each pathologist's cytologic diagnosis ranged from 53% to 84% (53%, 71%, 83%, 82%, 84%), corresponding to increasing level of experience. The percentage of agreement with EBE was 77%, whereas combined experienced pathologist's diagnosis and EBE was 87%. Kappa equaled .45 for experienced cytopathologist's diagnosis or EBE alone. Kappa equaled .53 when the pathologist or EBE diagnosed an epithelial cyst, indicating results unlikely to occur by chance. CONCLUSION: The distinction of functional from epithelial ovarian cysts is best achieved by combining measurement of the tumor markers CEA and CA-125 with a high level of cytopathology experience