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Pulmonary tumor thrombotic microangiopathy: a clinical analysis of 30 autopsy cases
Hironori Uruga1, Takeshi Fujii, Atsuko Kurosaki
1Department of Respiratory Medicine, Respiratory Center, Toranomon Hospital, Japan. uruga.hironori@gmail.com
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.
Insights
Pulmonary tumor thrombotic microangiopathy (PTTM) is a rare, fatal condition. Early recognition in cancer patients with respiratory distress and hypercoagulability is crucial for potential intervention.
Area of Science:
- Oncology
- Pulmonary Medicine
- Pathology
Background:
- Pulmonary tumor thrombotic microangiopathy (PTTM) is a rare and fatal complication of malignancy.
- This study aimed to elucidate the clinical, pathological, and immunohistochemical features of PTTM.
Observation:
- PTTM was diagnosed in 1.4% of 2,215 autopsy cases of carcinoma.
- Progressive dyspnea and a hypercoagulative state were common findings.
- Gastric adenocarcinoma was the most frequent primary malignancy.
Findings:
- Immunohistochemistry revealed positive expression of vascular endothelial growth factor (96.6%) and tissue factor (100%) in tumor cells.
- Chest CT showed consolidation, ground-glass opacity, and nodules.
- Median survival after oxygen initiation was nine days.
Implications:
- Clinicians should suspect PTTM in cancer patients with acute respiratory insufficiency and hypercoagulability.
- Vascular endothelial growth factor and tissue factor may be significant in PTTM pathogenesis.
- PTTM is associated with a very poor prognosis.
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