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

Abstract

BackgroundPulmonary 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 presentationA 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.ConclusionThis 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.

Pulmonary tumour thrombotic microangiopathy

“…Usually DIC is rapid and associated with bleeding, whereas in malignancy, 'compensated DIC' can occur, wherein the rate of consumption of coagulation factors and platelets is slow; thrombotic manifestations exceed bleeding events [24]. Evidence for raised D dimer or FDPs has been a uniform finding in PTTM [8,24], with features of microangiopathic haemolytic anaemia (MAHA) or DIC in half of cases at presentation [8,[24][25][26].…”

“…The use of 2-(F-18)-fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET) has been reported in PTTM [8,25,35], and for example showed uptake in areas of primary lung cancer and consolidation pathologically proven to be PTTM [8]. PTTM may be PET negative however [28], which may relate to size of lesions or that certain histological subtypes of gastric carcinoma are less FDG-PET-avid [38].…”

Angiosarcoma in the chest

“…[15] The halo sign was considered unusual for metastatic gastric cancer. The bone lesion was not sclerotic (as would be typical for metastatic prostate carcinoma).…”

Pulmonary tumour thrombotic microangiopathy: a rare but underappreciated complication of malignancy

“…The histopathology from autopsy showed an arteriole with a tumour embolus associated with the fibrin (Figure, A) and fibrous intimal hyperplasia nearly occluding the lumen of these vessels (Figure, B). The acute and rapid nature of the condition makes antemortem diagnosis a significant challenge, although present in 3.3% of cases of carcinomas at post mortem examination . While there are no guidelines on management, case series describe imatinib, chemotherapy or targeted therapy aimed at the primary malignancy, or corticosteroid therapy as potential options …”

“…The acute and rapid nature of the condition makes antemortem diagnosis a significant challenge, although present in 3.3% of cases of carcinomas at post mortem examination . While there are no guidelines on management, case series describe imatinib, chemotherapy or targeted therapy aimed at the primary malignancy, or corticosteroid therapy as potential options …”