Lymphangitis Sarcamatosis from an Unlikely Source

We describe a case of Pulmonary lymphangitis carcinomatosis that progressed rapidly, within a one-week period, to respiratory failure and death in a 72-year-old male. Admitted with right sided thigh/flank pain in the absence of chest symptoms. His only past medical history was hypertension. Bilateral infiltrates were noted on admission chest X-ray. Subsequent CT chest, abdomen, and pelvis was done. Bilateral Psoas soft tissue abnormalities were noted on the CT pelvis. He proceeded to have an MRI pelvis followed by a CT guided biopsy of a psoas mass that demonstrated metastatic leiomyosarcoma. CT chest demonstrated bilateral infiltrates with features as described in keeping with lymphangitis carcinomatosis (figure 1). He developed respiratory symptoms including dry cough and SOB subsequently and was scheduled for bronchoscopy with transbronchial biopsy (TBBX). COVID nasopharyngeal PCR swab was twice negative. He became tachycardic and hypoxic with sats of 84% on room air and was deemed unsafe for TBBX which meant histological confirmation wasn't possible. He type 1 respiratory failure despite empiric treatment with antibiotics, steroids and high flow oxygen (airvow). Bronchoalveolar lavage samples were microbiologically negative for COVID, atypical bacteria, tuberculosis, and fungal cultures but demonstrated atypical epithelial cells suspicious for carcinoma. BNP wasnt elevated. Chemotherapy was considered by oncology colleagues but in light of poor prognosis and respiratory status, a palliative approach was favoured. We believe our findings suggest a diagnosis of lymphangitis carcinomatosis secondary to metastatic leiomyosarcoma based on clinical, radiological, and Bronchioalevloar lavage findings. The lymphangitic spread of sarcomas, or "pulmonary lymphangitic sarcomatosis" (PLS) is extremely rare, as sarcomas tend to disseminate hematogenously. Only a few cases of PLS have been reported in the literature. The most common presentation of sarcomatous metastasis to the lung is that of multiple well-circumscribed randomly distributed pulmonary nodules. In contrast to carcinomas, only 2-5% of sarcomas metastasize to lymph nodes, and these have not been shown to present with lymphangitic spread. The limited reports of PLS have been on one primary pulmonary angiosarcoma, intravascular bronchoalveolar tumors (epitheliod hemangioendothelioma), one limb cutaneous hemangiosarcoma, osteosarcomas, mesotheliomas with sarcomatoid features, and Kaposi sarcomas. This is the first case to our knowledge of pulmonary lypmhangitis associated with leiomyosarcoma.