PD-1 expression on CD8+ T cells regulates their differentiation within lung allografts and is critical for tolerance induction.

Immunological requirements for rejection and tolerance induction differ between various organs. While memory CD8+ T cells are considered a barrier to immunosuppression-mediated acceptance of most tissues and organs, tolerance induction after lung transplantation is critically dependent on central memory CD8+ T lymphocytes. Here we demonstrate that costimulation blockade-mediated tolerance after lung transplantation is dependent on programmed cell death 1 (PD-1) expression on CD8+ T cells. In the absence of PD-1 expression, CD8+ T cells form prolonged interactions with graft-infiltrating CD11c+ cells; their differentiation is skewed towards an effector memory phenotype and grafts are rejected acutely. These findings extend the notion that requirements for tolerance induction after lung transplantation differ from other organs. Thus, immunosuppressive strategies for lung transplant recipients need to be tailored based on the unique immunological properties of this organ.

Ex vivo sentinel lymph node mapping in laparoscopic resection of colon cancer.

AIM: The study examined the feasibility and potential benefit of ex vivo sentinel lymph node (SLN) mapping, including multilevel sectioning (MLS) and immunohistochemistry (IHC) in colon cancer patients undergoing laparoscopic colectomy. The secondary goals were (i) to identify patient and tumour characteristics that might influence the success of the SLN technique, (ii) to investigate the extent of lymphadenectomy required to encompass tumour-positive nonsentinel lymph nodes (NSLN) and (iii) to ascertain the association of SLN status with oncological outcomes. METHOD: SLN mapping was performed after specimen extraction using 1% Isosulfan blue. The SLNs were analysed with H&E staining after MLS, and if negative, IHC was performed. NSLNs were grouped by distance either greater than or less than 4 cm from the tumour. RESULTS: Seventy-one patients completed the study between 2003 and 2007. Using H&E with MLS, the accuracy of SLN mapping was 76%, sensitivity was 52% and the false-negative rate was 48%. Excluding patients with clinically positive lymph nodes resulted in a significant improvement in accuracy to 81% and decreased the false-negative rate to 30%. Furthermore, as the only positive NSLN > 4 cm from the tumour was grossly positive, SLN mapping with a 4-cm mesenteric cuff would have given 100% sensitivity in patients without macroscopically involved nodes. CONCLUSIONS: SLN mapping may be of value in selected patients. It may be possible to accurately stage patients with a 4-cm cuff of mesentery, although further validation of this proposal is required.

Allelic loss and the progression of breast cancer.

To study genetic changes and the evolution of breast cancer, we assayed for loss of heterozygosity (LOH) in 12 sets of synchronous carcinoma in situ (CIS) and invasive cancer, compared to normal control DNA. Microsatellite markers were used, which map to each nonacrocentric autosomal arm. Eight tumor sets demonstrated LOH of the same allele in both concurrent invasive cancer and ductal CIS, for a total of 18 chromosomal loci. Three of nine tumor sets showed LOH on 11p. In two of these sets, LOH was seen on 11p only in the invasive tumor, not the corresponding CIS. One of these tumors also exhibited allelic loss in the invasive tumor for 4 loci, all of which were retained in the noninvasive tumor. For two tumor sets, LOH was mirrored in matched ductal CIS, invasive tumor, and lymph node metastasis. The maintenance of LOH for certain loci throughout the stages of breast cancer suggests clonality of the cancer cells.

Allelic loss on a chromosome 17 in ductal carcinoma in situ of the breast.

Multiple tumor suppressor genes are implicated in the oncogenesis and progression of invasive carcinoma of the breast. To investigate the chronology of genetic changes we studied loss of heterozygosity on chromosome 17 in ductal carcinoma in situ, a preinvasive breast cancer. A microdissection technique was used to separate tumor from normal stromal cells prior to DNA extraction and loss of heterozygosity was assayed mainly using simple sequence repeat polymorphism markers and the polymerase chain reaction. Loss of heterozygosity on 17p was observed in 8 of 28 tumors (29%) when compared with normal control DNA, whereas no loss was seen on 17q, suggesting that at least one locus on 17p is involved early in the development of breast cancer.

Allelotyping of ductal carcinoma in situ of the breast: deletion of loci on 8p, 13q, 16q, 17p and 17q.

In order to determine which tumor suppressor loci are involved in preinvasive breast cancer, we have assayed for loss of heterozygosity (LOH) in ductal carcinoma in situ (DCIS). Areas of DCIS were microdissected from archival paraffin-embedded tissue. DNA was extracted, and LOH was determined by PCR of microsatellite markers that map to 39 autosomal arms. Either uninvolved lymph node or white cell DNA was used as normal control. A total of 61 samples of DCIS were assayed. The average number of informative tumors examined for each marker was 19 (range, 8-48). The median fractional allelic loss was 0.037. The highest percentage of LOH was shown for loci on 8p (18.7%), 13q (18%), 16q (28.6%), 17p (37.5%), and 17q (15.9%). LOH on 18q was found in 10.7% of informative tumors. Fractional allelic loss was associated with LOH on 17p, with high nuclear grade and with the comedo subtype of DCIS. LOH on 17p correlated with LOH on 17q and on 13q. Additional markers were used for 16q and 17p to determine the smallest common region of deletion. These data provide evidence that tumor suppressor loci that map to these regions are involved in the oncogenesis of breast cancer before progression to the invasive phenotype. Our findings provide additional support that multiple loci on 17p and 16q are involved in the development of breast cancer.

Inhibition of inducible nitric oxide synthase ameliorates functional and histological changes of acute lung allograft rejection.

BACKGROUND: We recently demonstrated that inhibition of inducible nitric oxide synthase (iNOS) ameliorated severe acute lung allograft rejection. This study used a rat lung transplant model to determine (1) the time course and cellular localization of iNOS expression during the histological progression of unmodified acute rejection and (2) whether inhibition of iNOS prevented impaired gas exchange function of the allograft lung and/or ameliorated the histological changes of acute rejection. METHODS AND RESULTS: iNOS mRNA and enzyme activity were expressed in allograft lungs during mild, moderate, and severe acute rejection, but not in normal, isograft, or allograft lungs before histological changes of mild acute rejection. iNOS expression in allografts resulted in elevated serum nitrite/nitrate levels, indicative of increased in vivo nitric oxide (NO) production. In situ hybridization demonstrated iNOS mRNA expression in infiltrating inflammatory cells, but not in allograft parenchymal cells. Allografts had significantly impaired gas exchange, which was prevented with the selective iNOS inhibitor aminoguanidine (PaO2 of 566+/-19, 76+/-22, and 504+/-105 mmHg for isograft, allograft, and aminoguanidine-treated allograft, respectively; P<0.0002). Aminoguanidine also significantly improved the histological rejection scores. CONCLUSIONS: (1) iNOS expression and increased NO production occurred during the early stages of acute rejection, persisted throughout the unmodified rejection process, and localized to infiltrating inflammatory cells, but not allograft parenchymal cells; (2) aminoguanidine ameliorated the histological and functional changes of acute rejection; and (3) increased NO production, detected by the presence of iNOS mRNA, protein, or noninvasively by measuring serum nitrite/nitrate levels, may serve as an early marker of acute allograft rejection.

Epstein-Barr virus DNA in peripheral blood leukocytes of patients with posttransplant lymphoproliferative disease.

We tested the hypotheses that Epstein-Barr virus (EBV) DNA levels in peripheral blood leukocytes (PBL) of transplant recipients with posttransplant lymphoproliferative disease (PTLD) (1) exceed those of patients without PTLD, (2) rise with or before clinical detection of the disease, and (3) fall with effective therapy. Using the polymerase chain reaction (PCR) and an endpoint dilution technique, we compared EBV DNA levels in sequential specimens from 5 patients with PTLD, 16 solid organ transplant recipients without PTLD, and 5 young adults with primary infectious mononucleosis (IM), and in single specimens from 21 healthy seropositive subjects. EBV DNA levels in the first two groups rose with induction of immunosuppression despite prophylactic acyclovir. Markedly elevated levels of EBV DNA were seen in 4 of 5 patients with PTLD at or before clinical diagnosis. The peak levels in these patients exceeded those of transplant recipients without PTLD (P = 0.02) and healthy adults with IM (P = 0.02). EBV DNA levels fell dramatically with effective therapy. Four of 21 healthy seropositive subjects demonstrated low levels of EBV DNA, similar to levels seen late in the course of patients with IM. We conclude that a semiquantitative PCR assay for EBV DNA in PBL can assist in the detection of PTLD and in monitoring the effect of therapy.

Ruptured pulmonary infarction: a rare, fatal complication of thromboembolic disease.

We describe 2 men, ages 69 and 49 years, who experienced fatal rupture of pulmonary infarcts. Both patients had documented prior thromboembolic events and subsequently had abrupt deterioration in cardiorespiratory function. Autopsies showed massive unilateral hemothorax in both patients. Rupture of a pulmonary infarct may occur spontaneously or iatrogenically due to aggressive anticoagulation. This may be difficult to distinguish from secondary hemothorax with an intact pleura, but rupture typically has a considerably more rapid clinical evolution. Treatment should include immediate withdrawal of thrombolytic or anticoagulant medications and evacuation of the pleural space. Surgical intervention can be considered, although the utility of that approach must await prospective trials.

Inflammatory sarcomatoid carcinoma of the lung: report of three cases and clinicopathologic comparison with inflammatory pseudotumors in adult patients.

Although the capacity for some pulmonary carcinomas to mimic sarcomas is well recognized, their potential resemblance to selected benign lesions of the lung is currently underappreciated. The authors herein report three examples of sarcomatoid bronchogenic carcinoma with a deceptively bland appearance and an investment of reactive inflammation, such that they resembled pseudotumors histologically. These lesions occurred in two men and one woman who were 44, 61, and 63 years old, respectively, at diagnosis. All patients presented with a productive cough, hemoptysis, or chest pain. Their pulmonary masses were irregularly marginated radiographically, and ranged in size from 2.5 to 5.5 cm. Two were treated with lobectomy, and one underwent a wedge excision, followed by radiotherapy to the thorax. Despite these measures, each patient with inflammatory sarcomatoid carcinoma (ISC) died of disease or is likely to do so. Microscopically, ISCs were composed of uniform spindle cell proliferations with only modest nuclear pleomorphism, limited mitotic activity, and an arrangement in fascicles, storiform configurations, or haphazard arrays. Lymphocytes and plasma cells were interspersed throughout each of them, and keloidal stromal collagen was apparent internally in two examples. Two of the neoplasms also invaded pulmonary blood vessels or bronchi. A comparison group of 10 adults with pulmonary inflammatory pseudotumors (IPs) of the fibrous histiocytoma type shared several clinical attributes with ISC and showed closely similar histological features, except that the IPs lacked mitoses and invasiveness, and contained xanthoma cells or multinucleated elements in some cases in this series. Immunohistochemical analyses showed consistent dissimilarities between ISC and IP; keratin and epithelial membrane antigen were present in ISC but not IP, whereas actin was observed only in the proliferating spindle cells of IP. In summary, the potential clinicopathologic overlap between ISC and IP suggests that caution should be exercised in the separation of these two lesions. In particular, it is unwise to attempt to make this distinction in an intraoperative frozen section setting.

Expression of bcl-2 protein in stage T1N0M0 non-small cell lung carcinoma.

The bcl-2 gene product (bcl-2 protein, BCLP) prevents apoptotic cell death. Via a 14;18 chromosomal translocation, BCLP is overexpressed in most follicular lymphomas as well as some other non-Hodgkin's lymphomas, and it has also been documented in other nonlymphomatous malignancies. To address the possible prognostic value of this marker in predefined subsets of non-small cell lung carcinoma (NSCLC), the authors studied 126 T1N0M0 cases seen between the years 1986 to 1991 at our institution. Patients were treated by lobectomy (105 cases) or wedge excision (21 cases) with negative margins; neuroendocrine carcinomas of all grades were specifically excluded. The mean follow-up period was 39 months. Immunostaining for BCLP was done using a monoclonal antibody (clone no. 124; DAKO, Carpinteria, CA), and the avidin-biotin-peroxidase complex (ABC) technique. The study cases included 73 adenocarcinomas (ACs) as well as 40 squamous cell (SCC), five adenosquamous (ASC), and eight large cell/poorly differentiated (LCC) carcinomas. As assessed with the Kaplan-Meier method, overall survival was 64% at 5 years (66% AC vs 59% SC). BCLP was detected in 47 of 126 cases (37%) including 32 AC (44%), 10 SCC 925%), two ASC (40%), and three LCC (38%). No significant difference in 5-year survival was noted in a comparison of all cases with BCLP expression (63%) and those without (59%). There was, however, a significant difference in the survival of grade 1 BCLP(+) cases, when compared with grade 2 or 3 BCLP(+) cases (P = .01). A nonstatistically significant trend toward increased survival was observed in BCLP(+) SCC cases (66% 5-year survival in BCLP[+] vs 45% in BCLP[-] [P = .11]). Proportional hazards analysis failed to disclose significant independent risk factors. These data suggest that bcl-2 protein immunoreactivity has limited prognostic value in the pathological evaluation of NSCLC.

Adenovirus-mediated gene transfer of human interleukin 10 ameliorates reperfusion injury of rat lung isografts.

OBJECTIVE: The objective of this study was to examine the feasibility of human interleukin 10 gene transfer into rat lung isografts and to investigate the effect of gene transfer on subsequent ischemia-reperfusion injury. METHODS: Male F344 rats were divided into 4 groups and underwent left lung isotransplantation. Twenty-four hours before harvest, 5 x 10E9 pfu (group I, n = 6) or 1 x 10E10 pfu (group II, n = 7) of AdRSVhIL-10 was intravenously administered to donor rats. In group I-C (n = 6) and group II-C (n = 6), serving as controls, 5 x 10E9 pfu and 1 x 10E10 pfu of AdCMVLacZ were administered, respectively. Grafts were preserved for 18 hours at 4 degrees C before implantation and assessed 24 hours after reperfusion. Transgene expression of human interleukin 10 was assessed by both reverse transcriptase-polymerase chain reaction and immunohistochemistry. Graft inducible nitric oxide synthase, tumor necrosis factor alpha, intercellular adhesion molecule-1, growth-regulated gene product/cytokine-induced neutrophil chemoattractant-1, and monocyte chemotactic protein-1 mRNA expression were assessed by reverse transcriptase-polymerase chain reaction. Isograft gas exchange, exhaled nitric oxide, and myeloperoxidase activity were also analyzed. RESULTS: Dose-dependent transgene expression was detected by reverse transcriptase-polymerase chain reaction and immunohistochemistry. Arterial PO (2) in groups I (164.72 +/- 85.3 mm Hg) and II (153.19 +/- 113 mm Hg) was significantly higher than in groups I-C (82.37 +/- 19.1 mm Hg) and II-C (77.95 +/- 33.4 mm Hg) (P =.022 and P =.031, respectively). Arterial PCO (2) in group I (33.40 +/- 6.80 mm Hg) was significantly lower than in group I-C (51.23 +/- 11.9 mm Hg) (P =.0096). Myeloperoxidase activity in group II (0.083 +/- 0.031 DeltaOD. min(-1). mg(-1)) was significantly lower than in group II-C (0.117 +/- 0.028 DeltaOD. min(-1). mg(-1)) (P =.044). The inducible nitric oxide synthase mRNA expression in group II (0.627 +/- 0.28) was significantly lower than in group II-C (1.125 +/- 0.63) (P =. 039). CONCLUSION: Adenovirus-mediated human interleukin 10 gene transfer in vivo into lung isografts ameliorates subsequent ischemia-reperfusion injury. This results in improved graft gas exchange, reduced neutrophil sequestration, and down-regulation of graft inducible nitric oxide synthase mRNA expression.

Lipid-mediated ex vivo gene transfer of viral interleukin 10 in rat lung allotransplantation.

BACKGROUND: Recent studies suggest that viral interleukin 10 suppresses alloimmune response in transplantation and that cationic lipids are one of the most promising nonviral vehicles for gene therapy. The aim of this study was to examine the effect of ex vivo lipid-mediated viral IL10 gene transfer into rat lung allografts on subsequent rejection. METHODS: Male F344 rats (RT1lvl) underwent left lung transplantation with allografts from Brown Norway rats (RT1n). Allografts were transvascularly transfected 15 minutes after harvest with 5 mL of 1:20-diluted (group 1, n = 7) or 1:40-diluted (group 2, n = 6) GL67-pCMVievIL-10 complex. Group 3 (n = 7), serving as the control group, received 1:40-diluted GL67-pCF1-chloramphenicol acetyltransferase complex. All allografts were preserved for 3 hours at 10 degrees C before transplantation. In all groups recipients were killed on postoperative day 5. Transgene expression of viral interleukin 10 was assessed by means of both reverse transcriptase-polymerase chain reaction and immunohistochemistry. Histologic rejection score, allograft gas exchange, exhaled nitric oxide level, and allograft cytokine mRNA expression were also assessed. RESULTS: Dose-dependent transgene expression of viral interleukin 10 was detected by means of both reverse transcriptase-polymerase chain reaction and immunohistochemistry. Allograft gas exchange (PaO2) in groups 1 (114.06 +/- 61.1 mm Hg) and 2 (108.58 +/- 35.7 mm Hg) was significantly better than that in group 3 (66.4 +/- 8.22 mm Hg; P =.020 and P =.023, respectively). The vascular rejection score in group 1 was significantly lower than that in group 3 (P =.032, Kruskal-Wallis test). Exhaled nitric oxide levels in group 2 (5.150 +/- 6.38 ppb) were significantly lower than those in group 3 (13.517 +/- 10.4 ppb; P =.039). Allograft interleukin 2 mRNA expression levels in group 1 (1.123 +/- 0.23 relative units) were significantly lower than those in group 3 (1.753 +/- 0.71 relative units; P =.038 vs group 3). CONCLUSIONS: Lipid-mediated ex vivo viral IL10 gene transfer into rat lung allografts improved graft gas exchange, reduced histologic rejection scores, downregulated graft interleukin 2 mRNA expression, and reduced exhaled nitric oxide levels by postoperative day 5. These results suggest a therapeutic potential of graft viral IL10 gene transfer as an effective immunosuppressive strategy against lung allograft rejection.

Inhibition of inducible nitric oxide synthase ameliorates rat lung allograft rejection.

Recently, the inducible isoform of nitric oxide synthase has been shown to be an important immunomodulation molecule in allograft rejection. We have observed the production of nitric oxide during rejection and the effect of nitric oxide synthase inhibition on allograft rejection in a rat lung transplant model. Rat left lung allotransplants were performed in two strain combinations: brown Norway-to-F344 (major histocompatibility complex incompatible); and Lewis-to-F344 (minor loci incompatible) as severe and mild rejection models respectively. Syngeneic F344-to-F344 transplants were performed as a negative control. Nitric oxide production during rejection was determined by measuring the recipient's serum nitrite/nitrate levels as a stable end product of nitric oxide. The progression of rejection was evaluated radiographically and the grade of rejection was determined histologically. After operation, recipients of allotransplantation were randomly divided into two groups and received either aminoguanidine (200 mg/kg, intraperitoneal every 6 hours), a potent inducible nitric oxide synthase inhibitor, or normal saline treatment. The levels of serum nitrite and nitrate in recipients increased in the early phase of rejection in both allotransplant combinations. However, in the terminal phase of rejection, the serum nitrite/nitrate level decreased significantly compared with the peak level in the brown Norway-to-F344 recipients. The serum nitrite/nitrate levels in the syngeneic transplant recipients were normal during the entire observation period. In aminoguanidine-treated animals, serum nitrite/nitrate levels remained normal in both allograft combinations. Significant suppression of rejection in aminoguanidine-treated recipients was observed histologically and radiographically in comparison with untreated recipients in the brown Norway-to-F344 combinations. In the Lewis-to-F344 combination, aminoguanidine treatment significantly ameliorated histologic rejection but did not affect radiologic appearance. We therefore conclude nitric oxide is produced during early allograft rejection and may prove to be a marker and mediator of early rejection. The inhibition of inducible nitric oxide synthase results in significant reduction in rat lung allograft rejection.

Expression of intercellular and vascular cell adhesion molecules and class II major histocompatibility antigens in human lungs: lack of influence by conditions of organ preservation.

BACKGROUND: The expression of intercellular adhesion molecule-1, vascular cell adhesion molecule-1, and class II major histocompatibility complex antigens was studied in control lung tissue and preserved human donor lungs. The three controls were represented by wedge biopsy specimens taken from non-neoplastic lung surrounding bronchogenic carcinomas. METHODS: Nine lungs were harvested from six brain-dead donors, flushed with Euro-Collins solution or low potassium-dextran-glucose solution, and stored at 1 degree C or 10 degrees C. Samples of the latter organs were taken at the time of surgical harvest (baseline) and after 2, 12, 24, and 48 hours of preservation time. Immunostains with monoclonal antibodies against intercellular adhesion molecule-1, vascular cell adhesion molecule-1, and class II major histocompatibility complex molecules were performed on all samples, and the relative presence of these determinants was evaluated. RESULTS: In both the controls and preserved lungs, intercellular adhesion molecule-1 expression was intense in the septal capillary endothelium and alveolar pneumocytes, but essentially absent in bronchial epithelium. Vascular cell adhesion molecule-1 was moderately to strongly labeled in the endothelia of large and small blood vessels of all types, and it was not seen in other cell types. Class II major histocompatibility complex antigens were variably observed in pulmonary epithelial cells, but they were not expressed by endothelia. There appeared to be no significant difference in the immunohistologic density of intercellular adhesion molecule-1 or vascular cell adhesion molecule-1 immunostaining in allografts at the specified time points of preservation; this conclusion was confirmed by Western blot analysis. Similar findings pertained to staining results for human leukocyte DR antigens. There was likewise no significant difference in the expression of the three analytes when donor lungs perfused with Euro-Collins solution versus low potassium-dextran-glucose solution were compared; this was also true of organs preserved at 1 degree C versus 10 degrees C. CONCLUSIONS: These results suggest that, in the immediate post-harvest period, modulations in the expression of intercellular adhesion molecule-1, vascular cell adhesion molecule-1, or class II major histocompatibility complex antigens in pulmonary allografts are not attributable to the influences of preservation conditions.

Sarcomatoid carcinomas of the lung: a clinicopathologic review.

Sarcomatoid carcinomas (SC) of the lung are the most common pulmonary neoplasms that exhibit a composition by spindled or pleomorphic tumor cells. As such, many of them may be confused easily with true sarcomas diagnostically unless special immunohistological or ultrastructural analyses are performed. Reactivity is expected for keratin, epithelial membrane antigen, or collagen type IV in the sarcomalike elements in SC, although it may be focal. Electron microscopy often shows the presence of junctional complexes between tumor cells, with or without pericellular basal lamina and cytoplasmic skeins of intermediate filaments. Current terminological preferences are such that several formerly used terms--including "spindle-cell carcinoma," "pulmonary blastoma," "squamous cell carcinoma with pseudosarcomatous stroma," "pseudosarcoma," and "carcinosarcoma"--are now encompassed by the more generic designation of "sarcomatoid carcinoma." The clinical course of patients with this neoplasm is aggressive, with an overall 5-year survival rate approximating 20%.

Neuroendocrine neoplasms of the lung.

Neuroendocrine tumors of the lung continue to be difficult nosologic and diagnostic problems, centering on the time-honored terms of "carcinoid," "atypical carcinoid," and "small cell carcinoma." Problems that are encountered in the classification of such neoplasms revolve around the differing criteria that have been advanced for their definition and variable application of such criteria in common practice. This review considers the epithelial and nonepithelial lesions of the lung that may demonstrate neuroendocrine and neuroectodermal differentiation. A proposal is made for a simplified system of classifying the epithelial tumors, dividing them into 3 grades with appended descriptive modifiers.

Genital angiomyofibroblastoma. Comparison with aggressive angiomyxoma and other myxoid neoplasms of skin and soft tissue.

Angiomyofibroblastoma (AMFB) of the genital region is a relatively recently described tumor of the superficial soft tissues with a marked preference for female patients. Three cases of AMFB were reviewed, two of which involved adult men. To further elucidate the pathologic features of AMFB, these three cases were compared with 10 cases of aggressive angiomyxoma (AA), a salient diagnostic alternative, and 28 cases of other myxoid tumors that may show morphologic similarities to these neoplasms. Conventional histologic and immunohistochemical features of AMFBs were compared with those of AA, myxoid leiomyoma, myxoid leiomyosarcoma, myxoid liposarcoma, myxoid malignant fibrous histiocytoma, myxoid neurofibroma, and myxoid malignant peripheral nerve sheath tumor. The ultrastructure of two of the three AMFBs also was analyzed. Genital AMFBs were circumscribed, partially myxoid proliferations that demonstrated considerable variation in cellular density. Neoplastic elements were bland cytologically and showed both fusiform and epithelioid profiles, with a tendency to concentrate around intralesional blood vessels. Mitotic activity and necrosis were absent, and the vessels assumed an arborizing configuration and were venule or capillary sized. In contrast, all other tumor types evaluated were infiltrative, cytologically atypical, or both. All AMFBs showed immunoreactivity for vimentin, desmin, actin, and estrogen receptor protein. These results were shared by most examples of AA and smooth muscle tumors as well, but were not seen in any other neoplasms in this study. Electron microscopic findings in cases of AMFB supported the presence of myofibroblastic differentiation in the tumor cells. These results indicate that conventional morphologic analysis is paramount in the recognition of genital AMFB but that immunohistology may be helpful in a limited context in excluding other differential diagnoses. They also support the conclusion that AMFB, AA, and superficial smooth muscle tumors have similar morphotypes and immunohistologic attributes regardless of their origin in men or women.

Lymphoid lesions of the gastrointestinal tract: a histologic, immunophenotypic, and genotypic analysis of 49 cases.

The diagnosis of gastrointestinal (GI) lymphoid infiltrates can be challenging when based only on conventional microscopic assessment. When marked cytologic atypia is present, a diagnosis of malignant neoplasm is readily made; however, the distinction between a low-grade malignant neoplasm and a reactive process is much more difficult. If unfixed tissue is available, immunohistologic or genotypic methods that are usually aimed at defining B-lymphocytic monotypism can be applied. However, paraffin-embedded tissue has generally been deemed unsuitable for these techniques. We assessed the value of a panel of immunohistochemical stains and a seminested polymerase chain reaction (PCR) for the analysis of lymphoid infiltrates in routinely processed GI biopsy specimens from 49 archival cases, including morphologically benign, indeterminate, and overtly malignant lesions. Clinical outcome was used as the retrospective diagnostic standard; end points were death (of lymphomatous disease or otherwise) and clinical evidence of lymphoma. According to light microscopic criteria, 19 cases were classified as benign, 17 as malignant, and 13 as atypical. Immunophenotyping correctly identified 28 of 31 benign and 14 of 18 malignant lesions (7 cases had an indeterminate immunoprofile). Genotypic analysis correctly identified 12 of 18 malignant and 29 of 31 benign lesions, but spurious monoclonal bands were produced by PCR amplification of 2 of the latter 31 cases. No single technique exists for correct categorization of all paraffin-embedded specimens of GI lymphoid infiltrates. We recommend a sequential approach to the use of available diagnostic modalities.

False-positive interpretations of carcinoma in exfoliative respiratory cytology. Report of two cases and a review of underlying disorders.

The false-positive interpretation of malignancy is a potential pitfall of exfoliative respiratory tract cytopathology. However, the underlying causes of this problem are still relatively under-recognized. The authors herein present two additional examples in which bronchial brushing and washing specimens were misinterpreted as showing carcinoma of the lung. The first case concerned a patient with a granulomatous mass that simulated a malignancy on chest radiographs and was the apparent cause of atypical bronchial squamous metaplasia (ABSM). Exfoliated cells from the latter process were thought to explain the false-positive cytologic result in that instance. In the second case, a large-cell angiocentric T-cell lymphoma replaced the lower lobe of the left lung. It was likewise associated with ABSM as the cause of a mistaken diagnosis of carcinoma in exfoliative respiratory cytology specimens, representing the first instance of such an association of which the authors are aware. Repeated evaluation of all bronchial cytology samples by several experienced pathologists yielded no reliable observations that might have been used to avoid an erroneous interpretation in either case. A review is provided of the spectrum of underlying conditions that may be associated with false-positive respiratory cytology results.

Homologous carcinomas of the breasts, skin, and salivary glands. A histologic and immunohistochemical comparison of ductal mammary carcinoma, ductal sweat gland carcinoma, and salivary duct carcinoma.

Morphologic mimicry among human malignant neoplasms is a well-known phenomenon in surgical pathology; both undifferentiated and "committed" neoplasms may exhibit this trait. One particularly common group of histologic simulants includes ductal carcinomas of the breasts, the cutaneous appendages, and the salivary glands. One hundred three tumors in this structural cluster were analyzed microscopically and immunohistologically to codify points of potential pathologic similarity and difference. All the lesions were typified by irregularly permeative clusters and cords of atypical polygonal cells with variable luminal differentiation. A proportion of primary neoplasms in each site demonstrated in situ ductal components; in the absence of the latter elements, however, it was not possible to make topography-related morphologic distinctions among them. Immunostains for gross cystic disease fluid protein-15 (GCDFP-15), carcinoembryonic antigen, S100 protein, c-erbB-2 oncoprotein, estrogen receptor protein, and progesterone receptor protein also showed largely overlapping phenotypes in each of the three tumor categories, with selected exceptions. These differences were elucidated through paired chi 2 analysis and included a statistically significant infrequency of GCDFP-15 in eccrine sweat gland carcinomas, a paucity of carcinoembryonic antigen in breast cancers, and an absence of estrogen receptor protein in salivary duct carcinomas. Such findings may be useful in predefined differential diagnostic settings involving the distinction between primary and metastatic ductal cancers of the breasts, skin, and salivary glands. Nevertheless, because of the striking homologies between such tumors at structural and protein-synthetic levels of comparison, it is mandatory that all available clinicopathologic information be used in this context.