Pulmonary tumour thrombotic microangiopathy: unclassifiable pulmonary hypertension?

Impact of an expert-derived, quick hands-on tool on classifying pulmonary hypertension in chest computed tomography: a study on inexperienced readers using RAPID-CT-PH

PURPOSE

To test the inter-reader agreement in classifying pulmonary hypertension (PH) on chest contrast-enhanced computed tomography (CECT) between a consensus of two cardio-pulmonary-devoted radiologists (CRc) and inexperienced readers (radiology residents, RRs) when using a CECT-based quick hands-on tool built upon PH imaging literature, i.e., the "Rapid Access and Practical Information Digest on Computed Tomography for PH-RAPID-CT-PH".

MATERIAL AND METHODS

The observational study retrospectively included 60 PH patients who underwent CECT between 2015 and 2022. Four RRs independently reviewed all CECTs and classified each case into one of the five PH groups per the 2022 ESC/ERS guidelines. While RR3 and RR4 (RAPID-CT-PH group) used RAPID-CT-PH, RR1 and RR2 (control group) did not. RAPID-CT-PH and control groups' reports were compared with CRc using unweighted Cohen's Kappa (k) statistics. RRs' report completeness and reporting time were also compared using the Wilcoxon-Mann-Whitney test.

RESULTS

The inter-reader agreement in classifying PH between the RAPID-CT-PH group and CRc was substantial (k = 0.75 for RR3 and k = 0.65 for RR4); while, it was only moderate for the control group (k = 0.57 for RR1 and k = 0.49 for RR2). Using RAPID-CT-PH resulted in significantly higher report completeness (all p < 0.0001) and significantly lower reporting time (p < 0.0001) compared to the control group.

CONCLUSION

RRs using RAPID-CT-PH showed a substantial agreement with CRc on CECT-based PH classification. RAPID-CT-PH improved report completeness and reduced reporting time. A quick hands-on tool for classifying PH on chest CECT may help inexperienced radiologists effectively contribute to the PH multidisciplinary team.

Improvement of Breast Cancer-Associated Pulmonary Tumor Thrombotic Microangiopathy With Carboplatin and Gemcitabine

We present the case of a 50-year-old woman with stage IV invasive ER+/PR-/HER2-ductal breast carcinoma who was admitted to the intensive care unit (ICU) with obstructive shock and hypoxic respiratory failure due to pulmonary tumor thrombotic microangiopathy (PTTM), which significantly improved with chemotherapy. Upon presentation, her heart rate was 145 beats/min, her blood pressure was 86/47 mmHg, her respiratory rate was 25 breaths/min, and her oxygen saturation was 80% in room air. She underwent a broad non-diagnostic infectious evaluation, received fluid resuscitation, and was placed on broad-spectrum antibiotics. Transthoracic echocardiography showed evidence of severe pulmonary hypertension with a pulmonary arterial systolic pressure (PASP) of 77 mmHg. She initially required oxygen via a high-flow nasal cannula (HFNC) at 40 liters/minute and 80% FiO2 and was subsequently placed on inhaled nitric oxide (iNO) at 40 parts per million (PPM) as well as norepinephrine and vasopressin drips for acute decompensated right heart failure. Despite her poor performance status, she was started on chemotherapy with carboplatin and gemcitabine. Over the ensuing week, she was weaned off supplemental oxygen, vasoactive agents, and iNO and discharged home. Repeat echocardiography performed 10 days after the initiation of chemotherapy demonstrated marked improvement in her pulmonary hypertension with a PASP of 34 mmHg. This case highlights the potential role of chemotherapy in altering the course of PTTM in select patients with metastatic breast cancer.

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.

Lentinuses A-B, two alkaloids from the marine-derived fungus Lentinus sajor-caju with potent anti-pulmonary fibrosis activity

By adding natural amino acids into the medium as sole nitrogen source, twenty-four compounds, including two new alkaloids lentinuses A-B (1-2) with a rare oxazinone core in marine natural products, one new natural product 3-acetamido-4-phenylfurazan (3), 9β-ergosterol (22) were firstly discovered from a marine fungus, and twenty known compounds (4-21, 23-24) were isolated from the marine-derived fungus Lentinus sajor-caju. The chemical structures of all these compounds were elucidated by HRMS, NMR spectroscopy and X-ray diffraction. Compounds 1-24 were evaluated for their inhibitory activity against TGF-β1-induced collagen accumulation in human fetal lung fibroblasts (HFL1). Compounds 2, 3, 12, 22, and 23 showed potent activity against TGF-β1-induced collagen accumulation and low toxicity to HFL1 cells. The binding mode of lentinus B (2) with TGF-β1 receptor was then performed by using Schrödinger software, and the result showed that lentinus B possesses a strong binding force such as hydrogen bonding and hydrophobic interactions to the protein, which may provide a theoretical basis to design more potent anti-fibrotic drugs in the future.

Fatal pulmonary tumour thrombotic microangiopathy in patient with ovarian adenocarcinoma: review and a case report

Background

Pulmonary tumour thrombotic microangiopathy (PTTM) is a fatal disease in which tumour cells embolize to the pulmonary vasculature leading to pulmonary hypertension and right heart failure. Early diagnosis is essential for timely treatment which can reduce intimal pulmonary vascular proliferation and prolong survival, improve the symptoms. Due to rare occurrences and no clear diagnostic guidelines the disorder usually is found post-mortem. We present a review of this rare disease and a case of post-mortem diagnosed pulmonary tumour thrombotic microangiopathy in a young female.

Case presentation

51 years old woman presented with progressively worsening dyspnea, right ventricular failure signs and symptoms. Computerized tomography denied pulmonary embolism. 2D transthoracic echocardiography demonstrated right ventricle dilatation and dysfunction, severely increased systolic pulmonary pressure. Right heart catheterization revealed pre-capillary pulmonary hypertension with mean pulmonary artery pressure of 78 mmHg, pulmonary wedge pressure of 15 mmHg, reduced cardiac output to 1.78 L/min with a calculated pulmonary vascular resistance of 35 Wood units, and extremely low oxygen saturation (26%) in pulmonary artery. Because of worsening ascites, pelvic magnetic resonance imaging was performed, tumours in both ovaries were diagnosed. Due to the high operative risk, detailed tumour diagnosis surgically was not established. The patient developed progressive cardiorespiratory failure, unresponsive to optimal heart failure drug treatment. A postmortem morphology analyses revealed tumorous masses in pre-capillary lung vessels, right ventricle hypertrophy, ovary adenocarcinoma.

Conclusions

An early diagnosis of PTTM is essential. Most cases are lethal due to respiratory failure progressing rapidly. Patients with a history of malignancy, symptoms and signs implying of PH should be considered of having PTTM. If detected early enough, combination of chemotherapy with specific PH therapy is believed to be beneficial in reducing intimal proliferation and prolonging survival, along with improving the symptoms.

Pulmonary Tumor Embolism and Pulmonary Tumor Thrombotic Microangiopathy Causing Rapidly Progressive Respiratory Failure: A Case Series

Pulmonary tumor embolism (PTE) and pulmonary tumor thrombotic microangiopathy (PTTM) are rare etiologies for rapidly progressive dyspnea in the setting of undiagnosed metastatic cancer. They occur most frequently in association with adenocarcinomas, with PTE being most frequently associated with hepatocellular carcinoma and PTTM being most commonly reported with gastric adenocarcinoma. Pulmonary tumor embolism and PTTM appear to be a disease spectrum where PTTM represents an advanced form of PTE. Pulmonary tumor embolism and PTTM are mostly identified postmortem during autopsy as the antemortem diagnosis remains a clinical challenge due to the rapidly progressive nature of these rare diseases. We report 2 cases of rapidly progressive respiratory failure leading to death, due to tumoral pulmonary hypertension resulting from PTE and PTTM, diagnosed postmortem. Both of the patients were middle-aged females, nonsmokers, and had a gastrointestinal source of their primary malignancy.

A case of pulmonary tumor thrombotic microangiopathy following lymphedema on the lower extremities

Pulmonary tumor thrombotic microangiopathy (PTTM) is a rare manifestation of malignancy. The antemortem diagnosis is difficult, since patients present with rapidly progressive symptoms. We recently observed a case of PTTM following lymphedema of the lower extremities. We did not reach a diagnosis, even after performing BAL and TBLB. The patient manifested pulmonary hypertension and died on the 9th day of admission. Autopsy revealed a tumor embolism in the pulmonary arterioles accompanied by fibrocellular epithelial cell proliferation, but the primary organ was not identified. To our knowledge, this is the first reported case of PTTM with lymphedema.

Pulmonary Tumor Thrombotic Microangiopathy with Administration of Pulmonary Vasodilator Resulting in Clinical Improvement Prior to Final Diagnosis

BACKGROUND The pathophysiology of pulmonary tumor thrombotic microangiopathy (PTTM) was recently revealed by autopsy. Considered rare, we suggest that this fatal disease is not rare, but has not been diagnosed pre-mortem. Some patients with pulmonary thromboembolism with unknown thrombus source or with sudden death have been treated for malignant carcinoma. We report a patient with PTTM who was successfully rescued acutely by treatment with soluble guanylate cyclase (sGC), resulting in appropriate palliative care. CASE REPORT An 80-year-old Japanese woman was transferred to our emergency room for severe dyspnea owing to type I respiratory failure. Her clinical findings indicated pulmonary thromboembolism, but we found no thrombus in either the pulmonary artery or inferior vena cava. However, we incidentally found gallbladder cancer with peritoneal metastases. These findings raised the suspicion of PTTM. We began concurrent sGC and direct oral anticoagulant (DOAC) on the assumption that PTTM had occurred, while performing peripheral pulmonary artery sampling for cytology, and pulmonary perfusion scintigraphy. Cytology revealed several aplastic cells; consequently, we finally diagnosed PTTM. Because she did not wish to undergo examination and active treatment for carcinoma, we initiated palliative care while continuing sGC. She was able to spend time with her family for more than 100 days, without dyspnea. CONCLUSIONS We must recognize PTTM, which is a lesser-known disease, and introduce diagnostic therapy with a pulmonary vasodilator, such as sGC, immediately, when we suspect PTTM, leading to appropriate clinical care.

Atypical pulmonary metastases in children: the spectrum of radiologic findings

Pulmonary nodules present a diagnostic challenge when they appear as atypical metastases in pediatric oncology patients. Chest computed tomography (CT) is the primary imaging modality for assessing lung nodules. In pediatric populations, Wilms tumor and osteosarcoma are the cancers most likely to produce pulmonary metastasis, both typical and atypical. This pictorial essay provides a thorough description of the specific radiologic features of atypical pediatric pulmonary metastases, and their pathogenesis and differential diagnosis. We also address diagnostic approaches to incidental lung nodules in healthy children found in the literature. Our aim is to help radiologists identify atypical lung metastases on CT, ensuring that children receive prompt, and potentially lifesaving, treatment.

Pulmonary Hypertension as a Complication of Pediatric Cancer

Pediatric cancer is a life threatening disease known to create multi-organ complications that further compromise medical management affecting patient morbidity and mortality. Pulmonary hypertension (PH) is becoming more recognized as a complication of cancer and its therapies but has not been well characterized in pediatrics. Cancer pathophysiology can be uniquely set up to promote pulmonary vascular injury and remodeling that is similar to PH patients without cancer. This highlights the need to evaluate for PH clinically and with routine testing such as echocardiography during the course of a patient's care even into adulthood. This review article will discuss the direct, indirect and therapy related aspects of cancer which can promote PH in these patients. This understanding is essential to target effective treatment options in a potentially fatal complication. Diagnostic and treatment algorithms are presented in relation to the most recent pediatric PH management guidelines.

Elevated Pulmonary Artery Systolic Pressure is Associated with Poor Survival of Patients with Non-Small Cell Lung Cancer

Purpose

Pulmonary hypertension (PH) is an important comorbidity of lung cancer, PH in lung cancer patients is gradually gaining interest because of its apparent high prevalence, but the impact of PH on the outcomes of lung cancer remains uncertain and had rarely been discussed. We aimed to evaluate the prevalence, determinants and prognosis value of elevated pulmonary artery systolic pressure (PASP) in non-small cell lung cancer patients.

Patients and Methods

In this retrospective study, subjects with a new and pathological confirmed diagnosis of lung cancer were enrolled. All patients underwent transthoracic echocardiography before received treatment. Pulmonary artery systolic pressure was measured by transthoracic echocardiography. Lung cancer subtypes were categorized by WHO classification of lung tumors. Hazard ratios (HR) were estimated by using Cox regression models.

Results

Among 612 non-small cell lung cancer (NSCLC) patients, 19.8% coexisted with PH. After adjustment for age, symptom, coagulation disorders, lymph node metastasis, distant metastasis, histological type, clinical stage, PASP ≥35mmHg was significantly associated with the decreased overall survival (OS) of NSCLC (P= 0.028). Moreover, PASP ≥45mmHg was an independent predictor for perioperative death. Independent factors of comorbid elevated PASP were age, the presence of intrapulmonary metastasis and coagulation disorders.

Conclusion

These findings suggest that PASP is an independent prognostic risk factor for NSCLC patients. Main determinants of elevated PASP are age, the presence of intrapulmonary metastasis and coagulation disorders.

An autopsy case of a patient with systemic sclerosis who developed marked pulmonary hypertension because of pulmonary tumor thrombotic microangiopathy caused by gastric carcinoma

We performed an autopsy on a patient with systemic sclerosis who developed uncontrollable pulmonary hypertension due to pulmonary tumour thrombotic microangiopathy (PTTM) caused by gastric carcinoma. The case was of a 62-year-old woman with systemic sclerosis who was admitted to the intensive care unit (ICU) with severe pulmonary hypertension accompanied by respiratory insufficiency. Pulmonary hypertension could not be controlled despite aggressive medical treatment including vasodilators. Approximately 10 days after admission, a unilateral pleural effusion developed. Thoracentesis was performed, and cytology examination of the pleural fluid revealed carcinomatous pleurisy. Because of the presence of a known gastric carcinoma, PTTM was clinically diagnosed. Although chemotherapy was administered, she died 33 days after ICU admission. An autopsy revealed diffuse fibrocellular intimal thickening of the peripheral pulmonary arterioles, which indicated PTTM. In patients with connective tissue disease complicated with pulmonary hypertension, it is necessary to differentiate not only pulmonary arterial hypertension but also other pathological conditions such as PTTM.

Pulmonary hypertension in metastatic breast cancer: a case of pulmonary tumour thrombotic microangiopathy

Pulmonary tumour thrombotic microangiopathy (PTTM) and pulmonary tumour emboli (PTE) are distinct but related complications of malignancy. The incidence of each is exceedingly rare, unfortunately often being diagnosed postmortem. Patients with PTTM and PTE typically present with dyspnoea associated with a rapid onset of hypoxia due to pulmonary hypertension (PH), and respiratory failure that is almost certain to be fatal. The prognosis is grim due to the rapidity of the clinical decline and difficulty in establishing an ante-mortem diagnosis. We present a case of new-onset severe PH in a young woman with a recently discovered breast mass. She presented with shortness of breath and experienced rapid deterioration of her cardiopulmonary status which we attributed to PTTM. With early initiation of chemotherapy, systemic steroids and sildenafil, the patient dramatically improved. Case reports have identified early use of steroids, phosphodiesterase inhibitors and other alternative therapies as providing possible benefit in PTTM.

Rare cause of pulmonary hypertension - pulmonary tumour thrombotic microangiopathy

Pulmonary tumour thrombotic microangiopathy (PTTA) is a rare but lethal cause of pulmonary hypertension (PHT). Its underlying mechanism is believed to be fibrocellular intimal proliferation and microthrombosis. It has been reported in association with gastric adenocarcinoma and breast, pancreatic and lung cancers. The diagnosis is often made on postmortem examination due to the absence of diagnostic criteria and its rare occurrence. We describe the case of a middle-aged man who presented with rapidly progressive PHT. He deteriorated into multiorgan failure despite aggressive medical therapy and died 4 weeks after his initial presentation. A postmortem examination confirmed the diagnosis of PTTA in addition to the finding of signet cell gastric adenocarcinoma. This case highlights the lethal nature of this rare condition, the ongoing challenges in making an antemortem diagnosis, and the importance of postmortem examination in determining the cause of death to provide closure for both, the treating physician and the family.

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.

Tumoral pulmonary hypertension

Tumoral pulmonary hypertension (PH) comprises a variety of subtypes in patients with a current or previous malignancy. Tumoral PH principally includes the tumour-related pulmonary microvascular conditions pulmonary tumour microembolism and pulmonary tumour thrombotic microangiopathy. These inter-related conditions are frequently found inpost mortemspecimens but are notoriously difficult to diagnoseante mortem. The outlook for patients remains extremely poor although there is some emerging evidence that pulmonary vasodilators and anti-inflammatory approaches may improve survival. Tumoral PH also includes pulmonary macroembolism and tumours that involve the proximal pulmonary vasculature, such as angiosarcoma; both may mimic pulmonary embolism and chronic thromboembolic PH. Finally, tumoral PH may develop in response to treatments of an underlying malignancy. There is increasing interest in pulmonary arterial hypertension induced by tyrosine kinase inhibitors, such as dasatanib. In addition, radiotherapy and chemotherapeutic agents such as mitomycin-C can cause pulmonary veno-occlusive disease. Tumoral PH should be considered in any patient presenting with unexplained PH, especially if it is poorly responsive to standard approaches or there is a history of malignancy. This article will describe subtypes of tumoral PH, their pathophysiology, investigation and management options in turn.

Pulmonary Tumor Thrombotic Microangiopathy: Case Report and Literature Review

Pulmonary tumor thrombotic microangiopathy (PTTM) is a rapidly progressive pulmonary disease complicated by malignancy. It manifests clinically as respiratory distress with pulmonary hypertension, progressive right sided heart failure, and sudden death. We describe a case of PTTM associated with metastatic gastric carcinoma. This case demonstrates the diagnostic diffi culties in such a rare and rapidly fatal oncological complication. More awareness among clinicians may help make a right diagnosis in the short time available. We also review the literatures to demonstrate the clinical characteristics that might provide clues towards an antemortem diagnosis, and may provide the key in treating PTTM.

Pulmonary tumor thrombotic microangiopathy and pulmonary veno-occlusive disease in a woman with cervical cancer treated with cediranib and durvalumab

Background

Pulmonary tumor thrombotic microangiopathy (PTTM) is a rare cause of pulmonary hypertension that is associated with malignancies and is marked by the presence of non-occlusive tumor emboli and fibrocellular intimal proliferation of small pulmonary arteries leading to increased pulmonary vascular resistance and right heart failure. The diagnosis of PTTM is challenging to make pre-mortem and guidelines on treatment are lacking.

Case presentation

A 45-year-old woman with advanced squamous cell carcinoma of the cervix developed symptoms of dyspnea and evidence of right heart failure during a phase I clinical trial with cediranib and durvalumab. After an extensive evaluation, pre-capillary pulmonary hypertension was confirmed by right heart catheterization. Vasodilator therapy was initiated but resulted in the development of symptomatic hypoxemia and was discontinued. Despite continued supportive care, she continued to decline and was transitioned to hospice care. At autopsy, the cause of her right heart failure was found to be due to PTTM with features of pulmonary veno-occlusive disease (PVOD).

Conclusion

PTTM and PVOD are important diagnoses to consider in patients with a malignancy and the development of right heart failure and may be manifestations of a spectrum of similar disease processes.

[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.

Pulmonary tumour thrombotic microangiopathy

PURPOSE OF REVIEW

Pulmonary tumour thrombotic microangiopathy (PTTM) describes tumour cell microemboli with occlusive fibrointimal remodelling in small pulmonary arteries, veins and lymphatics. Progressive vessel occlusion ultimately results in pulmonary hypertension, which is often severe and rapid in onset. PTTM is associated with carcinomas, notably gastric carcinoma, with vascular endothelial growth factor and platelet-derived growth factor (PDGF) signalling implicated in driving the intimal remodelling. PTTM is a rare cause of pulmonary hypertension, but given that up to a quarter of autopsy specimens from patients dying of carcinoma show evidence for PTTM, it is probably underdiagnosed.

RECENT FINDINGS

Until recently, prognosis in PTTM was universally abysmal from weeks to a few months. Diagnostic utilities include aspiration of tumour cells at wedged right heart catheterization, high-resolution computed tomography (HRCT) findings and computed tomography-positron emission tomography (CT-PET), although definitive diagnosis requires histological analysis. Reports of PTTM treated with a combination of targeted pulmonary vasodilator therapies, anticoagulation, specific chemotherapy and PDGF inhibition, for example using imatinib, suggest that these approaches can prolong survival.

SUMMARY

PTTM is increasingly recognized as an important cause of pulmonary hypertension, often in patients presenting with new-onset pulmonary hypertension and as yet undiagnosed malignancy. Prospects of survival are improving with targeted combination therapy, and early recognition and diagnosis are likely to be the key factors to improve outcome.

Insights on pulmonary tumor thrombotic microangiopathy: a seven-patient case series

Pulmonary tumor thrombotic microangiopathy (PTTM) is a disease process wherein tumor cells are thought to embolize to the pulmonary circulation causing pulmonary hypertension (PH) and death from right heart failure. Presented herein are clinical, laboratory, radiographic, and histologic features across seven cases of PTTM. Highlighted in this publication are also involvement of pulmonary venules and clinical features distinguishing PTTM from clinical mimics.

We conducted a retrospective chart review of seven cases of PTTM from hospitals in the greater Los Angeles metropolitan area.

Patients in this series exhibited: symptoms of cough and progressive dyspnea; PH and/or heart failure on physical exam; laboratory abnormalities of anemia, thrombocytopenia, elevated LDH, and elevated D-dimer; chest computed tomography (CT) showing diffuse septal thickening, mediastinal and hilar lymphadenopathy and nodules; elevated pulmonary artery pressures on transthoracic echocardiogram and/or right heart catheterization; and presence of malignancy. Tumor emboli and fibrocellular intimal proliferation were seen in pulmonary arterioles, while two patients had pulmonary venopathy.

PTTM is a devastating disease occurring in patients with metastatic carcinoma. An early diagnosis is challenging. Understanding the clinical presentation of PTTM and distinguishing PTTM from clinical mimics may help achieve an early diagnosis and allow time for initiation of treatment.

CT pulmonary angiography of adult pulmonary vascular diseases: Technical considerations and interpretive pitfalls

Computed tomography pulmonary angiography (CTPA) has become the primary imaging modality for evaluating the pulmonary arteries. Although pulmonary embolism is the primary indication for CTPA, various pulmonary vascular abnormalities can be detected in adults. Knowledge of these disease entities and understanding technical pitfalls that can occur when performing CTPA are essential to enable accurate diagnosis and allow timely management. This review will cover a spectrum of acquired abnormalities including pulmonary embolism due to thrombus and foreign bodies, primary and metastatic tumor involving the pulmonary arteries, pulmonary hypertension, as well as pulmonary artery aneurysms and stenoses. Additionally, methods to overcome technical pitfalls and interventional treatment options will be addressed.

Pulmonary Tumor Thrombotic Microangiopathy: A New Paraneoplastic Syndrome?

This report, based on data from a clinical case, proposes that pulmonary tumor thrombotic microangiopathy, an underdiagnosed cause of pulmonary hypertension and death in patients with adenocarcinoma, is a paraneoplastic syndrome (PNS). Clinicians in general must be alert to the presence or development of PNS that may precede, coincide with, follow, or herald the recurrence or the primary diagnosis of malignancy since early recognition facilitates prompt diagnosis and treatment.

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.