Case Presentation: A 55-year-old female admitted for evaluation of new-onset dyspnea on exertion, a week duration and progressed rapidly. The patient also endorsed fatigue, orthopnea, pedal edema, and chest pain. Patient was tachycardic in 100’s and saturation over 95% on 2L nasal cannula. The rest of her vitals were normal. At admission, the patient did not appear to be in distress, was having normal breath sounds. The left breast lower quadrant had a mass with skin thickening over it. Initial labs were normal including BNP and were also negative for pulmonary embolism on CTPA. The patient’s clinical status progressively worsened over the next two-weeks. She was transferred to the intensive care unit and needed high flow and later intubation to maintain saturation. ECHO showed pulmonary hypertension, an enlarged right atrium and ventricle and stiff septum. Cardiac catheterization did not show any significant CAD, and pulmonary artery pressure was around 60 mmHg. Repeat CTPA was also negative for pulmonary embolism, however, it was significant for enlarged pulmonary arteries, multiple osteolytic lesions, axillary and mediastinal lymphadenopathy. A Left breast mass biopsy was sent for the pathology reports. The patient deteriorated requiring vasopressors for maintaining blood pressure and passed away from cardiac arrest. Final anatomic diagnosis per pathology report was poorly differentiated invasive ductal breast carcinoma with diffuse liver, bone and lung metastasis. Microscopic findings included metastatic carcinoma in pulmonary and cardiac vasculature.
Discussion: Pulmonary tumor thrombotic microangiopathy (PTTM) is a disease entity caused by tumor cell embolization to the pulmonary vasculature and activation of the coagulation cascade and reactive intimal fibrotic changes leading to vascular stenosis. The resulting pulmonary hypertension progresses to cor-pulmonale. The most common etiologies include gastric adenocarcinoma, followed by lung, breast and colon cancer. Cough and progressive dyspnea tend to be the most common presenting symptoms. PTTM tends to be a challenging diagnosis, difficult to be differentiated from chronic thromboembolic pulmonary hypertension, and pulmonary veno-occlusive disease. The pathogenesis varying slightly by the involvement of both pre- and post-capillary vessels under the influence of various growth factors-VEGF, PDGF, tissue factor. No imaging study had been consistent at diagnosis PTTM including FDG-PET scans. Echocardiogram and right heart catheterization show elevated pulmonary pressures. Lung biopsy and microscopic visualization of tumor microemboli in the vasculature with reactive architectural changes remains the definitive diagnosis. Very few cases of PTTM have been diagnosed antemortem owing to the rapid progression and high mortality of the disease entity. Early diagnosis and initiation of chemotherapy and or growth factor antagonist may have some impact on pulmonary hypertension. However, the mean survival period following diagnosis tends to be around nine days.
Conclusions: PTTM has a very fatality and early diagnosis plays a vital role in initiating therapies to lower pulmonary hypertension. Given the non-specific imaging finding and rapid deterioration, very high clinical suspicion is needed to provide timely care. Though growth factor inhibitors like imatinib have been used successfully in a few patients, more timely diagnosis and treatment will help further delineate the disease pathology and responses to various therapies.