A rare incidence of primary pulmonary undifferentiated pleomorphic sarcoma detected as an endobronchial mass and treated by bronchoscopic resection: a case report and literature review

Rationale: Primary pulmonary undifferentiated pleomorphic sarcoma (PPUPS) is a highly malignant tumor with extremely rare occurrence and is known for its distinct cellular pleomorphism. This tumor lacks specific differentiation markers. Consequently, PPUPS diagnosis requires thorough exclusion of other tumors through a comprehensive assessment of clinical, histopathological, and radiological outcomes. Patient concerns: A male patient of age 78 years presented to the hospital showing symptoms of continuous cough and blood-stained sputum for 1 month. Chest computed tomography detected a massive solid mass in the right lower lobe, stretching toward the right main bronchus. An endobronchial tumor blocking the right main bronchus was detected by bronchoscopy. We then conducted comprehensive histopathological and immunohistochemical analyses to elucidate the tumor's characteristics. Diagnosis: On the basis of the findings of immunohistochemical and histopathological evaluations conducted for the specimen collected during bronchoscopic resection, the diagnosis of PPUPS was confirmed after other metastatic diseases and sarcomas were ruled out. Interventions: The patient declined further surgical treatment, radiotherapy, or chemotherapy, citing personal reasons and concerns. Outcomes: Owing to the increased surgical risk and the considerably reduced capacity of the patient's lung, clinicians avoided conducting radical surgical resection; this decision was made after careful evaluation by multidisciplinary experts from the fields of respiratory medicine, anesthesiology, and thoracic surgery and consultation with the patient's family. The patient survived for 38 months postoperation. Lessons: PPUPS can develop as a solitary endobronchial mass, appearing almost identical to primary bronchogenic carcinoma. For patients considered ineligible to receive radical surgery intervention, survival may be enhanced by promoting sustained local control through minimally invasive bronchoscopic resection. This approach confronts the established belief that the sole viable treatment option is aggressive surgical resection. Accurate diagnosis of PPUPS relies on high clinical suspicion and careful elimination of other sarcomas on the basis of immunohistochemical analysis findings.