The diagnostic challenge of pulmonary tumour thrombotic microangiopathy as a presentation for metastatic gastric cancer: a case report and review of the literature

BACKGROUND: Pulmonary tumour thrombotic microangiopathy (PTTM) is a rare complication of metastatic cancer with a distinct histological appearance which presents with dyspnoea and pulmonary arterial hypertension and leads to death in hours to days. It is a challenging diagnosis to make ante mortem, in part due to the rapid clinical decline. Herein, we report a case of a young woman initially felt to have pulmonary sarcoidosis but who then died eight days later from what was found at post mortem to be PTTM. CASE PRESENTATION: A 41 year old Caucasian woman presented with progressive dyspnoea. Computed tomography of her thorax showed diffuse tiny centrilobular nodules in a tree-in-bud appearance along with small volume mediastinal lymphadenopathy. A presumptive diagnosis of pulmonary sarcoidosis was made; bronchoscopy with transbronchial lung biopsy was arranged to confirm the diagnosis. However, she rapidly deteriorated and died eight days later. Post mortem examination revealed metastatic poorly differentiated gastric adenocarcinoma with PTTM being the final cause of death. CONCLUSION: This case demonstrates the diagnostic difficulties in such a rare and rapidly fatal oncological complication; a greater awareness amongst clinicians may help make a positive diagnosis in the short window of time available. Little is known about its pathogenesis, and even less about optimal management strategies. We review the literature to demonstrate the clinical characteristics that might provide clues towards an ante mortem diagnosis, and highlight how imatinib may provide the key to treating PTTM.