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 two 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. Preliminary findings have been reported in abstract form [1].