Pulmonary tumor thrombotic microangiopathy

Pulmonary tumor thrombotic microangiopathy caused by metastatic ovarian high-grade serous carcinoma: a case report and literature review

BACKGROUND

Pulmonary tumor thrombotic microangiopathy (PTTM) is a rare entity with poor prognosis, and often diagnosed postmortem. PTTM is resulting from tumor emboli induced activation of coagulation cascade, fibrin clot formation and fibrocellular intimal proliferation in pulmonary microvasculature.

CASE

The patient was a 65-year-old female, with past medical history of ovarian high-grade serous carcinoma, presented with chest pain and shortness of breath. The chest computed tomography (CT) revealed innumerable new lung nodules as well as small hazy and patchy opacities compared to the chest CT 2 months before current presentation. She developed progressive respiratory failure and expired. A lung-restricted autopsy showed diffuse subcentimetric nodules in bilateral lungs grossly. Microscopic examination revealed the lung parenchyma demonstrated numerous tumor emboli consisting of pleomorphic tumor cells with varying degrees of fibrin deposition and fibrocellular intimal proliferation in the pulmonary arterioles, small arteries, and capillaries in the alveolar septa. Immunohistochemistry confirmed the ovarian origin of the tumor cells. The findings were consistent with PTTM secondary to metastasis of ovarian high-grade serous carcinoma. Literature review of PTTM caused by ovarian cancer was conducted.

CONCLUSION

PTTM is a fatal entity with rare association with primary ovarian malignancy. This case study demonstrates the clinicopathological features of PTTM associated with high-grade serous carcinoma, and it will be the second case of PTTM with this association in the literature.

Pulmonary tumor thrombotic microangiopathy in occult early gastric cancer that was undetectable on upper endoscopy: a case report and review of similar cases

Background

Pulmonary tumor thrombotic microangiopathy (PTTM), a rare manifestation of metastatic cancer with poor prognosis, is characterized by subacute/acute fatal pulmonary hypertension. The main cause of PTTM is gastric cancer, and cases of early gastric cancer confirmed using autopsy have been reported. Moreover, several cases of early gastric cancer that are undetectable on endoscopy or macroscopic postmortem examination have been reported.

Case presentation

A previously healthy 50-year-old man presented with progressive dyspnea and cough for 1 month. Echocardiography suggested pulmonary hypertension. Computed tomography revealed diffuse lymphadenopathy, whereas blood work revealed an elevation in several serum tumor marker levels. Despite normal upper endoscopic findings, a presumptive diagnosis of PTTM due to gastric cancer was made based on pathological findings of cervical lymph node biopsy, which indicated signet ring cell carcinoma. Imatinib and tegafur/gimeracil/oteracil plus oxaliplatin therapy were started on day 7. The patient’s condition was initially stable. However, his symptoms suddenly progressed, and the patient died on day 8. Macroscopic postmortem examination revealed no abnormal gastric wall findings. Microscopically, PTTM was confirmed, and multiple serial sections of the stomach revealed early gastric cancer.

Conclusions

Despite normal endoscopic findings, micro-occult gastric cancer can lead to PTTM. Physicians should be aware of this disease presentation. Taking prompt action is needed when PTTM is suspected, even if the patient appears stable.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-021-02009-8.

A Long-term Survival Case of Pulmonary Tumor Thrombotic Microangiopathy due to Gastric Cancer Confirmed by the Early Diagnosis based on a Transbronchial Lung Biopsy

Pulmonary tumor thrombotic microangiopathy (PTTM) is an acute, progressive, and fatal disease. PTTM manifests as subacute respiratory failure with pulmonary hypertension, progressive right-sided heart failure, and sudden death. An antemortem diagnosis of PTTM is very difficult to obtain, and many patients die within several weeks. We herein report a case of PTTM diagnosed based on a transbronchial lung biopsy. In this case, we finally diagnosed PTTM due to gastric cancer because of its histological identity. The patient was administered chemotherapy, including angiogenesis inhibitors, against gastric cancer at an early age and survived for a long time.

Clinical Characteristics of Heart Failure from Case Reports Presented at the Regional Meeting of the Japanese Society of Internal Medicine

Objective To examine case reports presented at the Regional Meeting of the Japanese Society of Internal Medicine in order to clarify the underlying disease and prognosis of heart failure, which is often caused by non-cardiovascular diseases. Methods We examined 49,693 case reports from the Japanese Society of Internal Medicine database. A total of 2,893 reports were included after excluding 46,022 reports that did not include the term "heart failure" and 778 reports with no indications of symptoms of heart failure. We assessed each patient's basal disease, and according to the abstracts, we reported their prognosis as dead or alive. Results Of the 2,893 reports included, 1,952 (67.5%) and 941 (32.5%) had cardiovascular and non-cardiovascular diseases as the causes, respectively; these cases were attributed to 725 different diseases, 196 (27.0%) and 529 (73.0%) of which were cardiovascular and non-cardiovascular diseases, respectively. In addition, 91 different side effects were identified. The percentage of cases of heart failure-related mortality was significantly higher among the patients with non-cardiovascular diseases than in those with cardiovascular diseases (17.8% vs. 10.8%; p <0.001). Of the diseases reported as causes of heart failure in more than 10 reports, pulmonary tumor thrombotic microangiopathy (87%), multiple myeloma (50%), and amyloidosis (47%) accounted for the highest percentages of heart failure-related mortality. Conclusion Because heart failure is often caused by non-cardiovascular diseases, a broad study of case reports on internal medicine is important for cardiologists.

Pulmonary tumor thrombotic microangiopathy: a systematic review

Pulmonary tumor thrombotic microangiopathy (PTTM) is a fatal disease process in which pulmonary hypertension (PH) develops in the setting of malignancy. The purpose of this study is to present a detailed analysis of cases of PTTM reported in literature in the hopes of achieving more ante-mortem diagnoses. We conducted a systematic review of currently published and available cases of PTTM by searching the term “pulmonary tumor thrombotic microangiopathy” on the Pubmed.gov database. Seventy-nine publications were included consisting of 160 unique cases of PTTM. The most commonly reported malignancy was gastric adenocarcinoma (94 cases, 59%). Cough and dyspnea were reported in 61 (85%) and 102 (94%) cases, respectively. Hypoxemia was reported in 96 cases (95%). Elevation in D-dimer was noted in 36 cases (95%), presence of anemia in 32 cases (84%), and thrombocytopenia in 30 cases (77%). Common findings on chest computed tomography (CT) included ground-glass opacities (GGO) in 28 cases (82%) and nodules in 24 cases (86%). PH on echocardiography was noted in 59 cases (89%) with an average right ventricular systolic pressure of 71 mmHg. Common features of PTTM that are reported across the published literature include presence of dyspnea and cough, hypoxemia, with abnormal CT findings of GGO, nodules, and mediastinal/hilar lymphadenopathy, and PH. PTTM is a universally fatal disease process and this analysis provides a detailed examination of all the available published data that may help clinicians establish an earlier diagnosis of PTTM.

Gastric adenocarcinoma revealed by atypical pulmonary lymphangitic carcinomatosis

Pulmonary lymphangitic carcinomatosis (PLC) is a well-known form of tumour metastasis to the pulmonary lymphatic system or to the adjacent interstitial tissue resulting in thickening of the bronchovascular bundle and septa. Another type of tumour metastasis to the lung involves the pulmonary vascular system and is known as pulmonary tumour thrombotic microangiopathy (PTTM). In this article, we will describe the unusual case of a young Chinese woman with gastric adenocarcinoma revealed by atypical radiographic lesions consistent with both PLC and PTTM. We will discuss the existing evidence and hypotheses about the pathophysiology of both conditions.

[Pulmonary tumor thrombotic microangiopathy]

Pulmonary tumor thrombotic microangiopathy syndrome is a rare clinicopathological entity in which tumor cell micro-emboli in the pulmonary microcirculation induced thrombotic microangiopathy. This can cause respiratory failure, and acute or sub-acute right heart failure. Histological features include micro tumor emboli in the small arteries and arterioles of the lung associated with thrombus formation and fibro-cellular and fibro-muscular intimal proliferation. The diagnosis is however extremely difficult to make before death. Thus, most of the observations reported are based on autopsy data. Very rare diagnostic observations made before death suggest the potential effectiveness of chemotherapy. Many details remain to be elucidated, interdisciplinary research is a priority with close collaboration between pathologists and clinicians to better understand this, often fatal, syndrome. It may be that the use of targeted therapies will improve the very poor prognosis allowing survival of several weeks or months after diagnosis.

The Case of a Zebra That Was Misdiagnosed as a Horse: Pulmonary Tumor Thrombotic Microangiopathy, a New Paraneoplastic Syndrome, Mimicking PD-1-Induced Pneumonitis

A case report of a 47-year-old woman with triple-negative breast cancer on a clinical trial called PRIMETIME (NCT02518958) who received the anti-PD-1 inhibitor nivolumab and the experimental anticancer agent RRx-001 is presented. Although initially diagnosed and treated for anti-PD-1-induced pneumonitis, clinical and radiological abnormalities triggered further investigation, leading to the diagnosis of pulmonary tumor thrombotic microangiopathy (PTTM). This example highlights the importance of exercising due diligence in determining immune-related adverse events and suggests that PD-1-induced pneumonitis should be a diagnosis of exclusion rather than a diagnosis by default. A case history and review of the literature are presented for PTTM, which we propose to define as a paraneoplastic syndrome.

Pulmonary tumor thrombotic microangiopathy: the challenge of the antemortem diagnosis

Pulmonary tumor thrombotic microangiopathy (PTTM) is known as a rare and severe cancer-related pulmonary complication. Nowadays, fewer than 80 cases have been reported in the literature and very few cases have been diagnosed antemortem. We describe an autopsy case of PTTM associated with cancer of unknown origin. A 56-year-old male patient came to our attention due to a 2-day history of dyspnea. Analysis of the clinical context in combination with laboratory and imaging tests led us to suspect acute pulmonary thromboembolism. However, the computed tomography pulmonary angiogram was negative for thromboembolism; on the contrary it revealed multiple lymphadenopathy. Microscopic pulmonary tumor embolism was suspected and a lymph node biopsy was planned. However, the patient's condition progressively worsened; death occurred 3 days after admission. After autopsy, histologically extensive neoplastic emboli involved the small pulmonary arteries and arterioles, often admixed with fibrin thrombi. The involved and noninvolved arteries also demonstrated fibrocellular intimal proliferation causing marked luminal stenosis and occlusion. These pathological features were characteristic of PTTM, which should be distinguished from microscopic tumor embolism and should be considered in the differential diagnosis of acute/subacute cor pulmonale and pulmonary hypertension in cancer as well as in noncancer patients. We propose a review of the literature and an algorithm to improve PTTM antemortem diagnosis.

Pulmonary tumour thrombotic microangiopathy as a cause of new-onset pulmonary hypertension in a patient with metastatic low-grade serous ovarian cancer

A 78-year-old woman with metastatic low-grade serous ovarian cancer presented with rapidly progressive exertional dyspnoea and hypoxia, and was found to have new-onset severe pulmonary hypertension (PH) by right heart catheterisation. A diagnosis of pulmonary tumour thrombotic microangiopathy (PTTM) was made at autopsy. PTTM is a rare complication of advanced cancer that often presents as rapidly progressive PH or acute hypoxic respiratory failure. Widespread tumour cell emboli in the pulmonary arteries and arterioles are hypothesised to induce fibrocellular subintimal proliferation and microthrombi, leading to increased pulmonary vascular resistance and PH. PTTM arising from serous ovarian cancer is exceedingly rare, with only two previously reported cases. A discussion of the pathophysiology, diagnosis and management of PTTM is presented.

The diagnostic challenge of pulmonary tumour thrombotic microangiopathy as a presentation for metastatic gastric cancer: a case report and review of the literature

Background

Pulmonary tumour thrombotic microangiopathy (PTTM) is a rare complication of metastatic cancer with a distinct histological appearance which presents with dyspnoea and pulmonary arterial hypertension and leads to death in hours to days. It is a challenging diagnosis to make ante mortem, in part due to the rapid clinical decline. Herein, we report a case of a young woman initially felt to have pulmonary sarcoidosis but who then died eight days later from what was found at post mortem to be PTTM.

Case presentation

A 41 year old Caucasian woman presented with progressive dyspnoea. Computed tomography of her thorax showed diffuse tiny centrilobular nodules in a tree-in-bud appearance along with small volume mediastinal lymphadenopathy. A presumptive diagnosis of pulmonary sarcoidosis was made; bronchoscopy with transbronchial lung biopsy was arranged to confirm the diagnosis. However, she rapidly deteriorated and died eight days later. Post mortem examination revealed metastatic poorly differentiated gastric adenocarcinoma with PTTM being the final cause of death.

Conclusion

This case demonstrates the diagnostic difficulties in such a rare and rapidly fatal oncological complication; a greater awareness amongst clinicians may help make a positive diagnosis in the short window of time available. Little is known about its pathogenesis, and even less about optimal management strategies. We review the literature to demonstrate the clinical characteristics that might provide clues towards an ante mortem diagnosis, and highlight how imatinib may provide the key to treating PTTM.

The Potential Role of Inflammation Associated with Interaction between Osteopontin and CD44 in a Case of Pulmonary Tumor Thrombotic Microangiopathy Caused by Breast Cancer

Pulmonary tumor thrombotic microangiopathy (PTTM) is a rare and fatal cancer-related complication. We herein present a case of PTTM that diagnosed antemortem by lung scintigraphy and pulmonary microvascular cytology. The patient was treated with steroid pulse therapy. Although her symptoms temporarily improved, she died of respiratory failure. An autopsy showed PTTM, and an immunohistochemical analysis revealed the expression of osteopontin and CD44 in macrophages that had migrated into the PTTM lesions. These findings suggest that inflammation associated with the interaction between osteopontin and CD44 may play an important role in PTTM.

Fatal acute right heart failure in gastric cancer patients

Pulmonary tumor thrombotic microangiopathy (PTTM) is a rare condition causing pulmonary artery hypertension and acute right heart failure in patients with cancer. However, chest computer tomography shows negative finding of pulmonary thromboembolism. Serum D-dimer level may be elevated. Echocardiography reveals a dilated right ventricle and feature of pulmonary artery hypertension. Establishing this diagnosis can be very difficult, and most cases are diagnosed during autopsy, although a history of cancer may be a predictor. PTTM should be considered in all patients with apparent pulmonary artery hypertension and elevated D-dimer level, particularly when the patient is known to have an underlying malignancy, especially adenocarcinoma and most of all, the clinical manifestation is very rapidly progressive.

Cisplatin and short-term 5-Fluorouracil infusion for paraneoplastic microangiopathic hemolytic anemia in gastric cancer: a case report and review of the literature

Microangiopathic hemolytic anemia is a rare paraneoplastic syndrome accompanying adenocarcinoma of the stomach. We report on a patient presenting with anemia due to a combination of severe hemolysis and tumour bleeding, where the combination of cisplatin and 5-fluorouracil in a short course infusional regimen led to a complete response of the hematologic abnormalities in the first line setting. Relapse was successfully treated with second line docetaxel; however the response was relatively short-lived. Overall survival was 16 months from diagnosis, which compares favourably to the survival of other reported cases. The chemotherapy regimens used in previously reported similar cases are reviewed. We suggest that a regimen based on bolus 5-fluorouracil, possibly with a platinum, should be investigated as a possible regimen of choice.

A case report of pulmonary tumor thrombotic microangiopathy (PTTM) caused by esophageal squamous cell carcinoma

A 67-year-old male was referred to our hospital after being diagnosed with esophageal squamous cell carcinoma of the middle thoracic esophagus. The clinical stage was T1b(sm)N4M1 cStage IVb, so he was admitted to our hospital for systemic chemotherapy. He had sustained fever and a dry cough. Chest computed tomography showed the presence of irregular shadows, and unidentified respiratory insufficiency had progressed. A transbronchial lung biopsy revealed a pulmonary artery tumor embolus of esophageal squamous cell carcinoma. He developed DIC and died of respiratory failure on the 19th hospital day. The postmortem autopsy detected pulmonary tumor thrombotic microangiopathy accompanied by esophageal squamous cell carcinoma.

Pulmonary tumor thrombotic microangiopathy: a clinical analysis of 30 autopsy cases

OBJECTIVE

Pulmonary tumor thrombotic microangiopathy (PTTM) is a unique, rare and fatal form of pulmonary arterial tumor embolism. The aim of this study was to evaluate the clinical characteristics and pathological and immunohistochemical findings of PTTM.

METHODS

Autopsy records dated between January 1983 and May 2008 in our hospital were reviewed, and those of patients who died from pulmonary tumor embolism resulting from malignant neoplasm were retrieved. The relevant tissue slides were reevaluated and examined immunohistochemically to confirm the diagnosis.

RESULTS

Among 2,215 consecutive autopsy cases of carcinoma, 30 patients (1.4%) were diagnosed with definitive PTTM. The common symptom was progressive dyspnea. A hypercoagulative state was observed in all measured cases (n = 21). The chest computed tomography findings (n = 6) included consolidation, ground-glass opacity, small nodules and a tree-in-bud appearance. Perfusion scans were performed in seven patients, six of whom demonstrated multiple small defects. The median survival time after the initiation of oxygen supplementation was nine days. The most frequent primary site was the stomach (n = 18 ; 60%) , and the most frequent histological type was adenocarcinoma (28/30 ; 93.3%) . The immunohistochemical findings for tumor cells located within the tumor emboli were positive for vascular endothelial growth factor (28/29 ; 96.6%) and tissue factor (29/29 ; 100%).

CONCLUSION

Clinicians should suspect PTTM in cancer patients who exhibit acute worsening respiratory insufficiency accompanied by a hypercoagulative state without embolism in major pulmonary arteries. The PTTM patients evaluated in our study had very poor prognoses. Vascular endothelial growth factor and tissue factor may play important roles in PTTM.

Pulmonary tumor thrombotic microangiopathy in patients with low-grade ovarian serous neoplasm: a clinicopathologic review of 2 cases of a previously unknown association

Pulmonary tumor thrombotic microangiopathy (PTTM) is a rare complication occurring during tumor dissemination that can lead to severe, commonly unrecognized pulmonary hypertension, right-sided heart failure, and sudden death. Histologically, it is characterized by tumor microthrombi within small arteries and arterioles and associated fibrocellular and fibromuscular intimal proliferation. Gastric adenocarcinoma is the most common tumor type with this association. Of gynecologic malignancies, a single case of ovarian clear cell carcinoma has been linked to PTTM. We report 2 patients who underwent surgery with a preoperative diagnosis of pelvic mass. After surgery, the patients had unexplained progressive respiratory failure that led to their death. Autopsy revealed typical features of PTTM with tumor lymphangitic spread and microscopic tumor emboli within the lung arteries. In both cases, the primary tumor was an ovarian serous neoplasm of low malignant potential with widespread dissemination, 1 with microinvasion and progression to low-grade serous carcinoma. In this last case, mutational analysis for KRAS and BRAF genes was performed to confirm the association between the ovarian and the extraovarian tumor and rule out other primary tumors more commonly associated with this disease. PTTM is a distinct pathologic entity with very few cases reported in the literature, especially involving ovarian tumors. We report 2 cases of low-grade ovarian serous neoplasm, not previously reported with this association.

Cancer-related microangiopathic hemolytic anemia: clinical and laboratory features in 168 reported cases

Cancer-related microangiopathic hemolytic anemia (CR-MAHA) is a paraneoplastic syndrome characterized by Coombs-negative hemolytic anemia with schistocytes and thrombocytopenia. We reviewed and analyzed all cases of CR-MAHA reported since 1979 (the time of the last published review on this topic) according to predefined criteria. We found 154 cases associated with solid cancer and 14 with lymphoma. Among the solid cancers, gastric, breast, prostate, lung, and cancer of unknown primary (CUP) were most common; 91.8% of cancers were metastatic, and in 19.4% of solid cancers CR-MAHA did not occur until recurrence of cancer. Lymphoma cases included Hodgkin disease, angiotropic lymphoma, diffuse large cell lymphoma, and myeloma. Evaluation of the clinical and laboratory findings revealed that only a minority of cases presented with the features of thrombotic thrombocytopenic purpura (TTP) or atypical hemolytic uremic syndrome (aHUS), with the exception of prostate cancer, where aHUS was a common presentation. Compared to hereditary or immune TTP or aHUS, disseminated intravascular coagulation and pulmonary symptoms were more common in CR-MAHA. Plasma exchange or fresh frozen plasma was rarely effective except in prostate cancer patients with aHUS. CR-MAHA responded to antitumor therapy in many patients with gastric, breast, lung, and CUP cancers. These patients had a superior survival compared to patients without chemotherapy. Compared to the prognosis of patients with metastatic cancer without CR-MAHA, the prognosis of CR-MAHA patients was greatly inferior. There is evidence that some cases of CR-MAHA in lymphoma are immune mediated.

Pulmonary tumor embolism secondary to uterine corpus carcinosarcoma mimicking pulmonary thromboembolism

We herein report a case of pulmonary tumor embolism caused by hematogenous metastasis that mimicked pulmonary thromboembolism in a 62-year-old Japanese woman with a history of uterine corpus carcinosarcoma. The case suggests that tumor embolism must be included in the differential diagnoses of respiratory symptoms in patients with a history of malignancy. It also illustrates the usefulness of such findings as beaded, dilated pulmonary arteries by computed tomography (CT) and high (18)F-fluorodeoxyglucose (FDG) uptake by fusion FDG positron emission tomography/CT imaging for differentiating a pulmonary tumor embolism from pulmonary thromboembolism.

Pulmonary thrombotic microangiopathy caused by gastric carcinoma

Pulmonary tumour thrombotic microangiopathy (PTTM) is characterised by wide spread tumour emboli along with fibrocellular intimal proliferation and thrombus formation in small pulmonary arteries and arterioles. PTTM is a rare but fatal complication of carcinoma, but the pathogenesis remains to be clarified. An autopsy case of PTTM caused by gastric adenocarcinoma is described, in which tumour cells in the PTTM lesion had positive immunoreactivity for platelet-derived growth factor (PDGF) and PDGF receptor (PDGFR), and proliferating fibromuscular intimal cells also showed expression of PDGFR. In addition, the overexpression of PGDF was detected in the alveolar macrophages. These findings suggest that PDGF derived from alveolar macrophages and from tumour cells may act together in promoting fibrocellular intimal proliferation. To the best of the authors' knowledge, the possible involvement of activated alveolar macrophages in PTTM has not been previously reported.

Pulmonary tumor thrombotic microangiopathy in patients with gastric carcinoma: an analysis of 6 autopsy cases and review of the literature

Pulmonary tumor thrombotic microangiopathy (PTTM) is a rare clinicopathological entity causing severe pulmonary hypertension (PH). Its histological features include widespread tumor emboli of the small arteries and arterioles of the lung, associated with thrombus formation and fibrocellular and fibromuscular intimal proliferation. Although PTTM has drawn increased attention as a fatal complication of gastric carcinoma (GC), comprehensive studies are still lacking. In order to clarify clinical and pathological features of GC-induced PTTM, recent autopsy cases were analyzed with a review of the literature. Of 36 autopsy cases with GC, 6 (16.7%) were affected by PTTM. Four were male and 2 female, with a mean age of 72.7 years. Three patients presented with PTTM-related clinical manifestations and died of PTTM. They showed clear morphological evidence of PH. The other 3 patients had PTTM as an incidental finding irrespective of clinical manifestations or PH. No patient was diagnosed antemortem as PTTM. All PTTM cases were associated with advanced GC, with a histology of adenocarcinoma of poorly differentiated type (n=4) or signet-ring cell type (n=2). Expression of tissue factor and vascular endothelial growth factor was confirmed immunohistochemically in tumor cells in all cases. The results were all in line with previous studies. In addition, the current study revealed vascular lesions characteristic of PTTM morphology to be present exclusively in the lung. In conclusion, our study shows a 16.7% incidence of PTTM in GC patients, with half of them developing PH and dying of PTTM, confirming a clinical significance as a non-negligible lethal complication of GC. In addition to many known clinicopathological characteristics of PTTM, the current study pointed to some PTTM issues requiring clarification, including the pathogenesis of the exclusive pulmonary distribution of vascular lesions of PTTM. Since details remain to be elucidated, interdisciplinary research is a high priority with a close collaboration between pathologists and clinicians in order to overcome this lethal condition.

Osteopontin expression in pulmonary tumor thrombotic microangiopathy caused by gastric carcinoma

Pulmonary tumor thrombotic microangiopathy (PTTM) is characterized by fibrocellular intimal proliferation and thrombus formation in small pulmonary arteries and arterioles in patients with metastatic carcinoma. Osteopontin (OPN) is a multifunctional cytokine and adhesive protein, and has been demonstrated to be implicated in fibrosis, neointima formation, arterial occlusion by thrombus, and tumor metastases in cooperation with platelet-derived growth factor (PDGF) and vascular endothelial growth factor (VEGF). Herein is described an autopsy case of gastric adenocarcinoma with severe pulmonary hypertension due to PTTM. Histologically, tumor cell emboli markedly induced both fibromuscular intimal thickening and thrombosis, resulting in luminal stenosis and occlusion of small pulmonary arteries and arterioles. Tumor cells, both in the PTTM lesions and primary gastric carcinoma, had positive immunoreactivity for OPN, PDGF, and VEGF. In addition, proliferating fibromuscular intimal cells also showed expression of OPN, PDGF, and VEGF. These findings suggest that OPN may be involved in fibrocellular intimal proliferation and thrombus formation in PTTM together with PDGF and VEGF. To the best of the authors' knowledge this is the first report to demonstrate the possible involvement of OPN in PTTM. It is postulated that OPN is one of the candidate molecules for the development of PTTM.

Cancer awareness in atypical thrombotic microangiopathies

OBJECTIVE

To specify the clinical and biological characteristics of thrombotic microangiopathies (TMAs) associated with a recent diagnosis of cancer. PATIENTS AND Methods. Multicenter study involving 14 national centers. Cross-sectional analysis of 20 patients with cancer-associated TMAs included in our national registry from October 2000 to July 2007. Patients were also compared with 134 adult patients with an acquired idiopathic TMA by univariate analysis.

RESULTS

Patients with a cancer-associated TMA typically displayed severe weight loss, dyspnea, bone pain, as well as disseminated intravascular coagulopathy and massive erythromyelemia (75%, 55%, 50%, 41%, and 85% of cases, respectively). By contrast, these features were observed with a much lower incidence in patients with an idiopathic TMA (8.9%, 19.7%, 0.8%, 7.1%, and 17.5%, respectively). Moreover, median platelet count was higher (48 x 10(9)/l; range, 21-73 x 10(9)/l versus 19 x 10(9)/l; range, 10-38 x 10(9)/l, respectively) and median serum creatinine level was lower (74 microM [range, 68-102] versus 113 microM [range, 80-225], respectively). The activity of the specific von Willebrand factor-cleaving proteinase ADAMTS13 was detectable in 14/17 studied patients. Platelet count improvement was observed in only seven patients and paralleled the response to chemotherapy. Prognosis of patients with cancer-associated TMAs was very poor, with a 30-day and 2-year mortality rate of 50% and 95%, respectively.

CONCLUSION

Cancer-associated TMAs display specific features at onset that should prompt investigation of an underlying disseminated malignancy. In this context, chemotherapy rather than plasma is mandatory since TMA prognosis parallels that of cancer.

Pulmonary tumor thrombotic microangiopathy resulting from metastatic signet ring cell carcinoma of the stomach

Pulmonary tumor thrombotic microangiopathy is an unusual malignancy-related respiratory complication characterized by multiple microthrombi and intimal myofibroblast proliferation. Its clinical manifestation is subacute respiratory failure with pulmonary hypertension. Herein is reported a case of pulmonary tumor thrombotic microangiopathy associated with gastric signet ring cell carcinoma. A 51-year-old woman with gastric cancer died of subacute respiratory failure. Autopsy showed gastric signet ring cell carcinoma with diffuse metastasis of pulmonary lymphatics and pleurae; every organ examined lacked a space-occupying tumor mass. Histologically, proliferated intimal myofibroblasts obliterated most of the pulmonary vascular lumen, and a few stenosed vascular lumina contained cancer cells. In addition, pulmonary vasculature associated with intimal proliferation contained microthrombi. Most cancer cells in the stomach and pulmonary lymphatics were typical signet ring cells, whereas those in vascular lesions were cells of poorly differentiated adenocarcinoma without mucous production. Consistent with a previous report, the latter expressed vascular endothelial growth factor (VEGF) and tissue factor (TF). The proliferated intimal myofibroblasts also expressed type 2A serotonin receptor (5-HT(2A)). These findings suggest that local expression of VEGF, TF, and 5-HT(2A) may be linked to the pathogenesis of this unusual pulmonary complication.

A microscopic adenocarcinoma of the stomach with pulmonary tumor thrombotic microangiopathy in a 17-year-old male

Pulmonary tumor thrombotic microangiopathy (PTTM), characterized by widespread fibrocellular intimal proliferation of the small pulmonary arteries and arterioles in patients with metastatic carcinomas, has been reported in only few cases. In childhood, gastrointestinal tumors represent less than 5% of pediatric neoplasms, and carcinomas within this subgroup have been very rarely described, in particular those arising in the stomach. We report on a case of a microscopic gastric signet-ring cell carcinoma identified by serial step sections through the entire stomach at autopsy. The patient was a 17-year-old high school student with severe dyspnea and marked pulmonary hypertension due to PTTM. Although the combination of PTTM with gastric cancer is very rare in childhood, it should be considered in the differential diagnosis of primary pulmonary hypertension and progressive respiratory failure, as indicated by a review of previously reported cases.

Pulmonary tumor thrombotic microangiopathy caused by a gastric carcinoma expressing vascular endothelial growth factor and tissue factor

Pulmonary tumor thrombotic microangiopathy (PTTM) is a rare clinicopathological entity causing severe pulmonary hypertension. Its histological features include widespread tumor emboli along with fibrocellular intimal proliferation and thrombus formation in the small arteries and arterioles of the lungs. The result is occlusion or stenosis of the pulmonary vasculature, but the detailed pathogenesis has yet to be clarified in spite of the serious clinical manifestations. Herein is described the case of a 62-year-old man with a gastric adenocarcinoma who died of sudden cardiopulmonary arrest. The autopsy revealed advanced cancer disease as well as findings of PTTM, which seemed to be the cause of his unexpected death. The carcinoma cells were immunohistochemically positive for vascular endothelial growth factor (VEGF) and also for tissue factor (TF). There is another report suggesting that TF might play an important role in the pathogenesis of PTTM. Also, VEGF has been reported to be involved in a variety of forms of pulmonary hypertension and to be upregulated by TF. These findings suggest that VEGF and TF may be involved in the pathogenesis of PTTM. The present PTTM case, in which the tumor cells demonstrate the coexpression of VEGF and TF, is important in facilitating understanding of the lethal disorder in the future.

Tumor-related thrombotic pulmonary microangiopathy: review of pathologic findings and pathophysiologic mechanisms

We report a middle-aged woman who died 2 days after presenting with dyspnea and severe pulmonary hypertension of unknown etiology. Her symptoms were highly suggestive of pulmonary embolism, but clinical evaluations for that disease yielded negative results. Autopsy revealed a Krukenberg tumor of the left ovary, representing metastatic gastric carcinoma from an occult primary lesion. Although the lungs exhibited no gross evidence of pulmonary emboli or neoplasia, microscopic examination revealed diffuse microscopic metastases in the pulmonary arterial vasculature. The pulmonary arteries exhibited fibrocellular intimal proliferation with smooth muscle colonization of the luminal neoplastic lesions and associated microthrombi. This disease entity, known as tumor-related thrombotic pulmonary microangiopathy, results in generalized microvascular obliteration and subsequent pulmonary hypertension. It is a rare condition that is distinct from ordinary pulmonary thromboembolism and primary pulmonary hypertension. Tumor-related thrombotic pulmonary microangiopathy should be considered diagnostically by the autopsy pathologist in cases of rapidly evolving pulmonary hypertension in a middle-aged or elderly individual, or respiratory failure of unknown cause, especially if there is a history of a visceral malignancy.