This patient presented with dyspnea and pleuritic chest pain. She underwent a CTPA which revealed the above findings of lymphangitis carcinomatosis and multiple metastases, first presentation. 

A CT of the abdomen and pelvis demonstrated para-aortic lymphadenopathy and further osseous metastases, although no primary malignancy. A PET-CT was also performed, although no primary lesion was identified.

Lymph node biopsy demonstrated metastatic adenocarcinoma. The presumed origin was upper gastrointestinal tract, favored to be gastric carcinoma. 

The patient rapidly deteriorated and died shortly after this admission.