Pulmonary lymphangitic carcinomatosis secondary to ureteral cancer

Background: Pulmonary lymphangitic carcinomatosis (PLC) is a metastatic lung disease of malignant tumors that spread through pulmonary lymphatic vessels. Although prompt diagnosis and specific treatment of PLC are required due to the poor prognosis associated with this disease, it is often challenging to determine the primary cancer site. Case presentation: A 67-year-old Japanese woman presented to our hospital with a 10-day history of cough and dyspnea on exertion. Chest radiography and computed tomography (CT) revealed diffuse nodular opacities with interlobular septal thickening. Both bronchoalveolar lavage (BAL) and transbronchial lung biopsy (TBLB) revealed carcinoma cells with unknown origin. Contrast-enhanced CT depicted a mass in the right ureter with hydronephrosis, and retrograde urography showed a narrowing of the right ureter. Urine cytology from her right ureter via ureteral catheter also revealed atypical cells, highly suggestive of malignancy. Immunohistochemical examination of lung specimens via TBLB showed results consistent with lung metastasis of ureteral cancer. Therefore, we arrived at a diagnosis of PLC secondary to ureteral cancer. Conclusions: This case encouraged multidisciplinary discussion and a whole-body examination, including TBLB with immunohistochemistry, to determine the origin of PLC.