Pulmonary Tumor Thrombotic Microangiopathy in a Patient With Gastric Adenocarcinoma.

SESSION TITLE: Pulmonary Vascular Disease Student/Resident Case Report Posters ISESSION TYPE: Medical Student/Resident Case ReportPRESENTED ON: Tuesday, October 28, 2014 at 01:30 PM - 02:30 PMINTRODUCTION: Pulmonary tumor thrombotic microangiopathy (PTTM) is a clinicopathologic entity with pulmonary tumor emboli and fibrocellular intimal proliferation that leads to acute pulmonary hypertension and sudden cardiovascular collapse in individuals with adenocarcinoma, usually of gastric origin. We report a case of PTTM diagnosed postmortem in a young Hispanic male with gastric carcinoma.CASE PRESENTATION: A 42 year old Hispanic male presented with 2 weeks of progressive dyspnea, non-productive cough, subjective fevers, and a 10 lb weight loss. Physical examination revealed tachypnea, hypoxemia with room air arterial oxygen saturation of 86%, and fine bibasilar rales. Chest X-ray suggested pulmonary edema (Panel A). CT pulmonary angiogram did not show evidence of pulmonary emboli, however, was notable for diffuse interlobular septal thickening, centrilobular micronodules and ground-glass opacities, and mediastinal, hilar, and upper abdominal lymphadenopathy (Panel B & C). An echocardiogram revealed severe right ventricular dilatation with estimated PA systolic pressure of 75 mmHg. A CT guided biopsy of a paraaortic lymph node revealed poorly differentiated adenocarcinoma likely of foregut origin. The patient's clinical course rapidly progressed to severe right heart failure, and was further complicated by respiratory failure requiring mechanical ventilation, acute renal failure requiring hemodialysis, and disseminated intravascular coagulation (DIC). Despite all efforts, the patient expired within 2 weeks of admission. Autopsy showed extensive tumour microemboli associated with proliferation of intimal fibromuscular cells and the formation of fibrin thrombi in the small pulmonary arteries and arterioles (Panel D - F) and poorly differentiated gastric adenocarcinoma with signet cells.DISCUSSION: PTTM is an extremely rare and fatal form of pulmonary arterial tumor embolism. The pathogenesis starts with formation of microscopic tumor cell emboli which induce local activation of coagulation and fibrocellular intimal proliferation. This leads to stenosis of pulmonary arterioles resulting in an increase in pulmonary vascular resistance causing pulmonary hypertension, hemolytic anemia, and DIC. Affected patients present with progressive dyspnea, cough, and signs of hypoxia and pulmonary hypertension. PTTM is very difficult to diagnose and most diagnoses are made post-mortem. The diagnosis may be established by pulmonary microvascular cytology, obtained through a wedged pulmonary artery catheter. No treatment has thus far been found to be of benefit. The disease progresses rapidly and is often fatal within a week or two of presentation.CONCLUSIONS: PTTM should be suspected in cancer patients with acute respiratory insufficiency and severe pulmonary hypertension in the absence of embolism in major pulmonary arteries.Reference #1: von Herbay A, Illes A, Waldherr R, Otto HF. Pulmonary tumor thrombotic microangiopathy with pulmonary hypertension. Cancer 1990; 66:587-592.DISCLOSURE: The following authors have nothing to disclose: Rohit Godbole, Abhijeet Ghatol, Jamie Betancourt, Nader KamangarNo Product/Research Disclosure Information.