Unusual Presentation of Primary Pulmonary Sarcomatous Cancer With Brain Metastasis: A Case Report.

Pulmonary sarcomatous carcinoma is a rare subtype of non-small cell lung cancer (NSCLC). This cancer has very low survival rates primarily due to its aggressive nature and propensity for early spread to abdominal organs and the skeletal system. Remarkably, brain metastasis is observed at later stages of the disease, likely attributing to the high fatality rate after the disease progresses to the brain tissue. In our case, a 79-year-old female with a 45-pack-year smoking history sought medical attention at a primary care clinic due to a 3-month history of recurrent right-sided chest pain. Notably, she denied cough, sputum production, palpitations, or syncope. CT chest revealed a 6.8 x 3.5 cm mass in the right upper lobe (RUL) of the lung, with evidence of obstruction and infiltration of the adjacent chest wall. A PET scan indicated increased uptake in the mass and the presence of smaller pulmonary nodules in both lungs, and multiple nodules in the upper left arm, abdomen, right inguinal region, left thigh, and cecum. Importantly, no intracranial lesions were detected. A subsequent colonoscopy yielded normal findings. Histopathologic examination of the lung mass and cell markers was consistent with a diagnosis of sarcomatous carcinoma of the lung. Only three days after the initial clinic visit, the patient presented with numbness and tingling in her lower extremities. Brain MRI revealed multiple bilateral brain metastases accompanied by significant vasogenic edema, prompting treatment with steroid therapy and brain radiation therapy. Subsequent chemotherapy/immunotherapy with Nab-paclitaxel /carboplatin/atezolizumab was initiated but led to significant treatment-related toxicities. Consequently, the treatment plan was adjusted to a single dose of single-agent immunotherapy using pembrolizumab. Unfortunately, the patient chose to discontinue treatment and eventually passed away after 13 days of palliative care. Compared to other lung cancer subtypes, brain metastasis in sarcomatous lung cancer is infrequent due to its lower prevalence among all lung cancer cases. Furthermore, sarcomatous lung cancer has a reduced propensity for developing brain metastasis when compared to other forms of non-small cell lung cancer (NSCLC). Regrettably, the prognosis for sarcomatous lung cancer with brain metastasis remains generally unfavorable, signaling an advanced stage of the disease with limited treatment options.