Causes of thrombophilia yet to be discovered: a personal view

Prediction of genetic risk factors for venous thrombosis might best be left for only wise soothsayers. Nonetheless, based on the principle that hypercoagulability, either systemic or vascular-bed-specific, predisposes to thrombosis, we venture some speculations. Hyperactivity of platelets could be caused by elevated numbers of surface glycoproteins or defective signal transduction pathways. The reported efficacy of aspirin for prevention of venous thrombosis is consistent with the prediction that certain platelet defects may increase the risk of venous thrombosis. Hyperlipidaemia is associated with hypercoagulability, and lipoproteins exhibit procoagulant (e.g. triglyceride-rich particles and oxidized low-density lipoprotein) or anticoagulant (e.g. high-density-lipoprotein's cofactor activity for activated protein C/protein S) activities. This leads to the prediction that defects in lipids and/or lipoproteins may increase the risk for venous thrombosis. Interestingly, statins were recently reported to prevent the occurrence of venous thrombosis in the HERS (Heart and Estrogen/Progestin Replacement) trial. We also predict that new defects in the protein C pathway (e.g. defective endothelial protein C receptor or novel cofactors for activated protein C/protein S) will be discovered. Risk factors affecting the majority of patients will likely involve new single nucleotide polymorphisms (SNPs) like the factor V nt G1691A or prothrombin nt G20210A SNPs. The Human Genome Project will soon accelerate discovery of new SNPs that are risk factors for venous thrombosis.

Plasma lipoproteins, hemostasis and thrombosis

Regulation of hemostasis and thrombosis involves numerous plasma factors that contribute to procoagulant and anticoagulant pathways. Lipid-containing surfaces provide sites where both procoagulant and anticoagulant enzymes, cofactors and substrates are assembled to express their activities. Plasma and lipoproteins can contribute to either procoagulant or anticoagulant reactions. Procoagulant lipids/lipoproteins include triglyceride-rich particles in plasma and oxidized low density lipoprotein (LDL) which can accelerate activation of prothrombin, factor X and factor VII. Potentially anticoagulant lipids and lipoproteins, each of which enhances inactivation of factor Va by activated protein C, include phosphatidylethanolamine, cardiolipin, the neutral glycosphingolipids glucosylceramide and Gb3 ceramide (CD77), and high density lipoprotein (HDL). Remarkably, treatment of hyperlipidemia with statins not only lowers lipids but also provides antithrombotic effects whose mechanisms remain to be clarified. We hypothesize that procoagulant and anticoagulant lipids and lipoproteins in plasma may contribute to a Yin-Yang balance that helps influence the up-regulation and down-regulation of thrombin generation.

Pemphigus foliaceus with prominent neutrophilic pustules

We describe four patients with generalized scaly and pustular skin lesions showing extensive neutrophilic infiltration in the subcorneal region of the epidermis. Immunofluorescence, immunoblot and enzyme-linked immunosorbent assay analyses detected IgG antibodies reacting exclusively with desmoglein 1, the pemphigus foliaceus antigen. This study indicates that pemphigus foliaceus may show prominent neutrophilic pustular skin lesions.

[Standard values of inter-inner canthal, inter-outer canthal, and inter-pupillary distances in normal Japanese infants and children]

PURPOSE AND MATERIALS: We studied inter-inner canthal distance(DIC), inter-outer canthal distance (DOC), and inter-pupillary distance (PD) in 1,006 normal Japanese infants and children to establish the normal ratio of DIC/PD and DOC/DIC for the diagnosis of congenital anomalies such as Waardenburg syndrome.

RESULTS

DIC, DOC, and PD increased significantly from one month after birth to 12 years of age. DIC and DOC were stable but PD increased from 13 years of age to 15 years of age in junior high school. The DIC/PD and DOC/DIC averages were 0.61 and 2.73, respectively, one month after birth and 0.63 and 2.69 at three months after birth. On the other hand, DIC/PD and DOC/DIC were stable at 0.55-0.59 and 2.45 from 8 to 15 years of age.

CONCLUSION

Since there have been no reports on standard values of DIC, DOC and PD in infants, we established the standard values in this study. These values are expected to be very useful in the diagnosis of neural crest cell migration anomalies, such as Waardenburg syndrome.

Prognostic significance of frequent acidophilic nuclear inclusions in adenocarcinoma of the lung with immunohistochemical and ultrastructural studies

BACKGROUND

Adenocarcinoma of the lung occasionally has acidophilic nuclear inclusions (ANIs). Some studies have reported that the incidence of ANIs was higher in well differentiated tumor types and have suggested that adenocarcinoma patients with ANIs might have a more favorable prognosis; however, to the authors' knowledge, statistically significant prognostic findings were not reported. The objective of the current study was to assess the prognostic significance of ANI in patients with pulmonary adenocarcinoma and, moreover, to characterize ANI immunohistochemically and ultrastructurally.

METHODS

Surgically resected tumor specimens from 147 patients with primary pure adenocarcinoma of the lung were examined. Only obvious ANIs surrounded by a clear halo on hematoxylin and eosin-stained slides were counted; the authors classified cases with > or = 10 ANIs per 10 high-power fields (/10 HPF) as frequent-ANI cases, cases with < 10 ANIs/10 HPF as infrequent-ANI cases, and cases without ANIs as non-ANI cases in the current study.

RESULTS

Nineteen frequent-ANI cases (12.9%) and 16 infrequent-ANI cases (10.9%) were found; the remaining 112 cases (76.2%) were considered to be non-ANI cases. The majority of ANIs immunohistochemically contained surfactant apoprotein and ultrastructurally corresponded to invagination of the inner nuclear membrane, showing a tubular or amorphous configuration. Frequent-ANI patients showed significantly better prognosis than the other two groups on both overall univariate analysis and univariate analysis limited to patients with International Union Against Cancer Stage I disease (P = 0.0096 and P = 0.0095, respectively). However, on the multivariate analysis only disease stage was shown to be a significant prognostic factor and frequent-ANI showed borderline significance (P = 0.0956).

CONCLUSIONS

Frequent ANIs appear to be of limited value in clarifying the prognosis of patients with lung adenocarcinoma.

Lung carcinoma with rhabdoid cells: a clinicopathological study and survival analysis of 14 cases

AIMS

We determined the clinicopathological features of primary lung carcinomas with rhabdoid cells by defining the immunophenotype of rhabdoid cells and analysing survival.

METHODS AND RESULTS

Rhabdoid cells are distinctive in having an eccentric nucleus and a large intracytoplasmic inclusion on routinely stained sections. Based on the number of rhabdoid cells, 45 cases of large cell carcinoma were divided into the following three types: lung tumour with a rhabdoid phenotype (LTRP) (n=4), lung carcinoma with a small number of rhabdoid cells (LCSR) (n=10), large cell carcinoma containing no rhabdoid cells (LCNR) (n=31). LTRP is composed of at least 10% rhabdoid cells. In LCSR the percentage of rhabdoid cells is less than 10%. LTRP and LCSR are associated with locally advanced disease. Immunohistochemical stains were positive for epithelial markers in all LTRP and eight LCSR, for neuroendocrine markers in one LTRP and three LCSR. The outcome is worse for patients with LTRP than LCSR or LCNR. LCSR shows a trend close to LCNR. Stage-matched survival analysis, however, revealed no statistically significant difference among the histological subtypes.

CONCLUSIONS

Rhabdoid cells are heterogeneous except for epithelial markers and vimentin positivity. Less than 5% of rhabdoid cells has a negligible effect on prognosis.

Plasma glucosylceramide deficiency as potential risk factor for venous thrombosis and modulator of anticoagulant protein C pathway

To assess the relationship between venous thrombosis and plasma glucosylceramide (GlcCer) or phosphatidylethanolamine (PE), plasma levels of GlcCer and PE were determined for 70 venous thrombosis patients referred for evaluation and 70 healthy blood donors. The mean GlcCer level, but not the PE level, was lower in patients versus controls (4.9 vs 6.5 microg/mL [P =.0007] and 66 vs 71 microg/mL [P =.48], respectively). As a measure of relative risk, the odds ratio for deep vein thrombosis in subjects with GlcCer levels below the 10th percentile of controls was 5.7 (95% CI, 2.3-14). To assess the influence of glycolipids on anticoagulant response to activated protein C (APC):protein S in modified prothrombin time assays, the effects of depleting endogenous plasma GlcCer by glucocerebrosidase treatment or of adding exogenous purified GlcCer or other neutral glycolipids to plasma were tested. Glucocerebrosidase treatment reduced plasma sensitivity to APC:protein S in parallel with GlcCer reduction. Exogenously added GlcCer and the homologous Glc-containing globotriaosylceramide (Gb3Cer), but not galactosylceramide, dose-dependently prolonged clotting times of normal plasma in the presence, but not absence, of APC:protein S, which suggests that GlcCer or Gb3Cer can enhance protein C pathway anticoagulant activity. In studies using purified proteins, inactivation of factor Va by APC:protein S was enhanced by GlcCer alone and by GlcCer in multicomponent vesicles containing phosphatidylserine and phosphatidylcholine. These results suggest that the neutral glycolipids GlcCer and Gb3Cer may directly contribute to the anticoagulant activity of the protein C pathway and that deficiency of plasma GlcCer may be a risk factor for venous thrombosis. (Blood. 2001;97:1907-1914)

Expression of SART3 antigen and induction of CTLs by SART3-derived peptides in breast cancer patients

We recently reported the SART3 tumour-rejection antigen as possessing tumour epitopes capable of inducing HLA-class I-restricted cytotoxic T lymphocytes (CTLs). This study investigated expression of the SART3 antigen in breast cancer to explore an appropriate molecule for use in specific immunotherapy of breast cancer patients. The SART3 antigen was detected in all of the breast cancer cell lines tested, 30 of 40 (75%) breast cancer tissue samples, and 0 of 3 non-tumourous breast tissue samples. SART3 derived peptides at positions 109-118 and 315-323 induced HLA-A24 restricted CTLs that reacted to breast cancer cells from the peripheral blood mononuclear cells (PBMCs) of breast cancer patients. Therefore, the SART3 antigen and its peptides could be an appropriate molecule for use in specific immunotherapy of the majority of HLA-A24-positive breast cancer patients.

Enterovirus RNA replication in cases of dilated cardiomyopathy: light microscopic in situ hybridization and virological analyses of myocardial specimens obtained at partial left ventriculectomy

OBJECTIVE

Recently, attention has been focused on enteroviral infection of the heart in the genesis of dilated cardiomyopathy (DCM). To determine the location of enteroviral RNA in the myocardium, we performed light microscopic in situ hybridization (ISH) and virological analyses of myocardial specimens obtained at partial left ventriculectomy (PLV).

METHODS

Posterolateral walls of the left ventricle from 26 DCM patients were examined. Myocardial specimens were tested for the presence of enteroviral genomes by polymerase chain reaction (PCR). We selected two age-matched groups (10 patients each) in which enteroviruses were either present (EV-plus group) or not (EV-minus group). For both groups, we examined in situ localization of enteroviral RNA in the myocardium by ISH.

RESULTS

In PCR studies, both sense and antisense enteroviral RNA were detected in the myocardium of seven patients in the EV-plus group. The presence of this RNA indicates active viral replication in the myocardium. Five of seven patients who exhibited both sense and antisense enteroviral RNA died early after surgery. On ISH, three patients had evidence of active replication of enteroviral genomes. Viral genomes were present in myocardial lesions, especially in endocardial sites. Viral signals were found in degenerating myocardial cells, interstitial inflammatory cells, and endothelial cells of small vessels. These positive signals were not detected in the myocardium of the EV-negative group.

CONCLUSIONS

We detected both sense and antisense enteroviral RNA in various myocardial lesions. This suggests that active enteroviral replication plays a role in the development of myocardial lesions in DCM patients. Active viral replication appears to be a prognostic factor for DCM after PLV. Further study of active viral replication in myocardial lesions will provide information useful for evaluating different therapeutic strategies for DCM.

Evaluation of viral infection in the myocardium of patients with idiopathic dilated cardiomyopathy

OBJECTIVES

The aim of this study was to evaluate the viral etiology of idiopathic dilated cardiomyopathy (DCM).

BACKGROUND

The demonstration of enteroviral genome in hearts with DCM has reinforced the importance of enteroviruses in the pathogenesis of DCM. However, there is uncertainty about the character and activity of enteroviruses detected in the myocardium. Recently, the association of hepatitis C virus or adenovirus with DCM has been reported.

METHODS

Myocardial specimens from 26 patients with idiopathic DCM, which were obtained at partial left ventriculectomy (PLV), were examined virologically. Strand-specific detection of enteroviral RNA was performed to differentiate active viral replication from latent persistence. Polymerase chain reaction was used to detect genomic sequences of hepatitis C virus, adenovirus, cytomegalovirus, influenza viruses, mumps virus, herpes simplex viruses, varicella-zoster virus and Epstein-Barr virus.

RESULTS

Plus-strand enteroviral RNA was detected in 9 (35%) of the 26 patients. Minus-strand enteroviral RNA was determined in seven (78%) of these nine plus-strand RNA-positive patients. Sequence analysis revealed that the enteroviruses detected were coxsackie B viruses, such as coxsackievirus B3 and B4. However, genetic material from other viruses was not detected. Six (86%) of seven minus-strand enteroviral RNA-positive patients died of cardiac insufficiency within the first six months after PLV.

CONCLUSIONS

Coxsackie B viruses were seen in hearts with idiopathic DCM. Active viral RNA replication appeared to be present in a significant proportion of these cases. Minus-strand coxsackieviral RNA in the myocardium can be a marker for poor clinical outcome after PLV. There was no evidence of persistent infection by other viruses in hearts with DCM.

Increased plasma levels of tissue factor pathway inhibitor-activated factor X complex in patients with disseminated intravascular coagulation

Plasma levels of tissue factor pathway inhibitor (TFPI)-activated factor Xa (FXa) complex were measured in patients with disseminated intravascular coagulation (DIC), pre-DIC, and DIC. Plasma levels of plasmin-plasmin inhibitor complex (PPIC), D-dimer, and soluble fibrin monomer (SFM) were significantly higher in patients with DIC than in those with pre-DIC or non-DIC; the levels of these hemostatic markers were significantly higher in patients with pre-DIC than in those with non-DIC. Plasma levels of thrombin-antithrombin complex (TAT) were significantly higher in patients with DIC or pre-DIC than in those with non-DIC. Plasma levels of tissue factor (TF), total TFPI, free TFPI, and TFPI-Xa complex were significantly higher in patients with DIC than in those with non-DIC. Plasma levels of TFPI-Xa complex were significantly increased in patients with pre-DIC as compared to those with non-DIC; however, plasma free TFPI levels were significantly decreased in patients with pre-DIC as compared to those with non-DIC. These findings suggest that free TFPI might be consumed in the pre-DIC state, thereby confirming the activation of the extrinsic pathway. Plasma levels of TFPI-Xa complex were significantly correlated with TF, free TFPI, and total TFPI. Increased plasma TFPI-Xa complex levels might be useful for the diagnosis of DIC or pre-DIC, particularly that occurring by activation of the extrinsic pathway of blood coagulation.

Hemostatic abnormalities in patients with thrombotic complications on maintenance hemodialysis

Before hemodialysis (HD), plasma levels of tissue factor (TF), free-TF pathway inhibitor (TFPI) and thrombomodulin (TM) were significantly higher in patients with HD than in healthy volunteers. Plasma levels of (T-F) TFPI and plasmin plasmin inhibitor complex (PPIC) were significantly higher in patients with HD than in healthy volunteers. During HD, plasma levels of TF and (T-F) TFPI were not significantly increased, but plasma levels of total TFPI and free TFPI at 1 hour after and at the end of HD were significantly increased, compared with levels before start of HD. Plasma level of PPIC 1 hour after start of HD was significantly higher than before start of HD, and plasma levels of thrombin antithrombin complex (TAT), PPIC, D-dimer, TM, and protein C (PC) at the end of HD were significantly higher than before start of HD. In patients with thrombosis complications, plasma TF levels were significantly higher than in patients without thrombotic complications during HD. Plasma levels of PC were significantly lower in patients with thrombotic complications than in patients without thrombotic complications. There was no significant difference between both groups during HD in hemostatic parameters, with the exception of TF and PC. Hemostatic abnormalities existed in patients with HD; especially, increased TF and decreased PC might cause thrombotic complications.

Refolding of firefly luciferase immobilized on agarose beads

The renaturation yield of the denatured firefly luciferase decreased strongly with increasing protein concentration in a renaturation buffer, because of aggregation. In this study, firefly luciferase was immobilized on agarose beads at a high concentration. Although the protein concentration was extremely high (about 100-fold) compared to that of soluble luciferase, the renaturation yield was comparable with that for the soluble one. Thus, immobilization was shown to be effective for avoiding aggregation of firefly luciferase. It was also shown that the optimum buffer conditions for renaturation of the immobilized luciferase were the same as those for the renaturation in solution. Also, it was indicated that electrostatic interactions between a protein and the matrix have a negative effect on renaturation of the immobilized luciferase since the renaturation yield decreased at acidic pH only for the immobilized luciferase. These novel observations are described in detail in this paper.

Cardiolipin is a normal component of human plasma lipoproteins

Anticardiolipin (anti-CL) antibodies, diagnostic for antiphospholipid antibody syndrome, are associated with increased risks of venous and arterial thrombosis. Because CL selectively enhances activated protein C/protein S-dependent anticoagulant activities in purified systems and because CL is not known to be a normal plasma component, we searched for CL in plasma. Plasma lipid extracts [chloroform/methanol (2:1, vol/vol)] were subjected to analyses by using TLC, analytical HPLC, and MS. A plasma lipid component was purified that was indistinguishable from reference CL (M:1448). When CL in 40 fasting plasma lipid extracts (20 males, 20 females) was quantitated by using HPLC, CL (mean +/- SD) was 14.9 +/- 3.7 microgram/ml (range 9.1 to 24.2) and CL was not correlated with phosphatidylserine (3.8 +/- 1.7 microgram/ml), phosphatidylethanolamine (64 +/- 20 microgram/ml), or choline-containing phospholipid (1,580 +/- 280 microgram/ml). Based on studies of fasting blood donors, CL (>/=94%) was recovered in very low density, low density, and high density lipoproteins (11 +/- 5.3%, 67 +/- 11.0%, and 17 +/- 10%, respectively), showing that the majority of plasma CL (67%) is in low density lipoprotein. Analysis of relative phospholipid contents of lipoproteins indicated that high density lipoprotein is selectively enriched in CL and phosphatidylethanolamine. These results shows that CL is a normal plasma component and suggest that the epitopes of antiphospholipid antibodies could include CL or oxidized CL in lipoproteins or in complexes with plasma proteins (e. g., beta(2)-glycoprotein I, prothrombin, protein C, or protein S) or with platelet or endothelial surface proteins.

[Trans-sternal bilateral thoracotomy for bilateral metastatic lung tumors]

Trans-sternal bilateral thoracotomy has been performed in 4 patients with bilateral metastatic lung tumors. The primary lesion was rectum in one case and the colon in three cases. Two patients were male and 2 were female. Their ages ranged from 63 to 78 years old. An inframammary incision was made with the patient in the supine position, and the chest was entered via the 4th or 5th intercostal space. This procedure provided excellent exposure of the entire mediastinum. Postoperative pain was comparatively severe in the early postoperative period, but was controlled by administering an epidural block. This procedure allows good exposure of the entire thoracic space through a single operative field. We conclude that trans-sternal bilateral thoracotomy is an excellent approach in the patient with bilateral metastatic lung tumors.

Expression of alpha-smooth muscle actin in small bronchioloalveolar adenocarcinoma of the lung: assessment and comparison with noguchi criteria

The Noguchi criteria are useful in assessing the prognosis of patients with small lung adenocarcinoma. Although there is a significant difference in prognosis between type A or B and type C, it is difficult in some cases to distinguish these types accurately by microscopy. In this study, we used immunohistochemistry to examine alpha-smooth muscle actin (alpha-SMA) produced by active fibroblasts in 25 pulmonary adenocarcinomas less than 2 cm in diameter. Eleven of type C (61%) showed positive staining for alpha-SMA, whereas no positive cases were seen in type A or B. The incidence of cancerous blood vessel and lymphatic invasion were significantly higher in alpha-SMA positive cases than in negative cases, and the positive cases showed poorer prognosis. These findings indicate that immunohistochemical detection of alpha-SMA is useful and essential for histological typing by the Noguchi criteria.

A case of interleukin-6-producing malignant fibrous histiocytoma originating in the heart

Primary cardiac malignant fibrous histiocytoma is extremely rare and its pathophysiological characteristics remain largely unknown. We treated a female patient with persistent fever and disseminated intravascular coagulation. Since ultrasonic echocardiography revealed the presence of a cardiac tumor and her serum interleukin-6 level was elevated, we speculated she had a cardiac myxoma. Histological examination of the surgically resected specimen, however, revealed that the tumor was malignant fibrous histiocytoma. Although her disseminated intravascular coagulation and heart failure were transiently improved after operation, local recurrence and systemic metastasis occurred and she died 7 weeks after operation. Using the autopsied specimen, we examined whether the malignant fibrous histiocytoma constitutively synthesized interleukin-6. The interleukin-6 content in the tumor was high, consistent with interleukin-6 production by the tumor. This was confirmed by immunohistochemical analysis. To our knowledge, this is the first report demonstrating interleukin-6 production by a cardiac malignant fibrous histiocytoma.

Increased truncated form of plasma tissue factor pathway inhibitor levels in patients with disseminated intravascular coagulation

To evaluate that the relationship between the truncated form of tissue factor pathway inhibitor (TFPI) and the stage of disseminated intravascular coagulation (DIC), we measured the plasma levels of tissue factor (TF) antigen and the intact and truncated forms of TFPI antigens in 41 patients with DIC, 12 with pre-DIC, and 20 with non-DIC. The plasma TF and total TFPI antigen levels were significantly higher in patients with DIC than in non-DIC patients. Plasma levels of intact TFPI antigen in the pre-DIC groups were significantly lower than in the non-DIC and DIC groups. The truncated form of TFPI antigen levels in DIC patients were significantly increased compared with those in non-DIC and pre-DIC patients. The fact that the intact form of TFPI was decreased in pre-DIC patients compared with that in non-DIC patients, suggests that it is consumed in the pre-DIC state and that hypercoagulability occurs in pre-DIC patients. The increased level of the truncated form of TFPI in DIC patients may be attributed to proteolysis of the intact form of TFPI in these patients. The increased level of the truncated form of TFPI may be a useful index for the diagnosis of DIC.

Ultraviolet light is an environmental factor aggravating facial lesions of adult atopic dermatitis

An increasing number of adult patients with atopic dermatitis (AD) in Japan are distressed by persistent eczematous lesions of the face (so-called atopic red face). Phototests were carried out in 28 patients with the atopic red face to test a possibility that ultraviolet (UV) light could be an aggravating factor. Contact and photocontact dermatitis had been ruled out by repeated patch and photopatch tests. All of the patients had a normal response to a screening dose of UVA (10 J/sq cm) and a normal minimal erythema dose (MED) of UVB. Ten of these patients, however, showed an abnormal papular response to a single or 3-times consecutive UVB radiation above the MED (90 mJ/sq cm).

Prothrombin and its derivatives stimulate motility of melanoma cells

Several studies indicated that activation of the clotting system may promote the growth and the invasive behavior of tumor cells. In the present study, we evaluated the migratory response of various melanoma cell lines to several clotting factors and prothrombin derivatives (thrombin, fragment 1, fragment 2 and kringle 1 fragment). Prothrombin, thrombin and fragment 1 stimulated chemotaxis of the murine (K-1735 M2, X21) and human A375 (SM) melanoma cell lines. Prothrombin and prothrombin fragment 1 showed their maximal chemotactic activity at 0.5 approximately 1 microM. Chemotaxis induced by thrombin was inhibited by hirudin, but not that induced by prothrombin or fragment 1. Other clotting proteins and the fragment 2 and kringle 1 fragment of prothrombin did not elicit chemotactic activity. Checkerboard analysis indicated that motility was directional with a significant chemokinetic component. The K-1735 M2 cells also migrated in a concentration-dependent manner to substratum-bound insoluble prothrombin, thrombin or fragment 1. Ligand binding assays showed that both prothrombin and fragment 1 bound to K-1735 M2 cells with apparent Kds of 0.5 microM. This binding was inhibited by an excess concentration of unlabeled prothrombin and fragment 1 but not by similar concentrations of other prothrombin fragments. These findings suggest that prothrombin and its fragment 1 exert chemotactic activity on melanoma cells by different mechanisms and different binding sites from that induced by thrombin.

Midterm results of thoracoscopic surgery for pulmonary metastases especially from colorectal cancers

Indications for thoracoscopic metastatectomy remain controversial because not all metastatic tumors may be detected without the manual palpation that is possible with thoracotomy. However, the accuracy (92%) of preoperative lung imaging in patients with one or two lesions led us to re-evaluate thoracoscopic metastatectomy with patient survival as the primary end point. Thoracoscopic wedge resection using an endoscopic stapling device or video-assisted thoracic surgery (VATS) lobectomy was performed in patients with one or two pulmonary metastases. Thoracoscopic resection was performed in 27 patients with 22 solitary lesions and 5 patients with two lesions. The primary tumors were colorectal cancer (15), testicular cancer (3), osteosarcoma (2), and seven other histologies. In 5 of 27 patients (18.5%) a thoracoscopic operation was converted to a VATS procedure, which requires minithoracotomy to identify metastasis primary by digital palpation. The 3-year survival rate for colorectal cancer patients who underwent thoracoscopic resection was 56.4%, in comparison to 48.6% in historical control thoracotomy patients (n = 16). There was no statistically significant difference between the two groups. Thoracoscopic resection of one or two colorectal cancer lung metastases results in a survival rate similar to standard thoracotomy, and thereby provides an acceptable alternative to this more invasive approach.