Abstract Spindle cell carcinoma (SpCC) is a rare and aggressive malignancy, accounting for only 0.1%-0.3% of lung tumors. More commonly found in the oral cavity, larynx, breast, gastrointestinal tract, and uterus, pulmonary involvement is uncommon. Clinical manifestations may include cough, dyspnea, hemoptysis, chest pain, fatigue, and weight loss. Diagnosis typically requires imaging followed by tissue biopsy, as sarcomatoid features can complicate classification. Although metastasis to the lungs from uterine cancers is documented, pulmonary metastasis of SpCC after hysterectomy has not been previously reported. We present the first known case of metastatic pulmonary SpCC in a patient with a history of uterine adenosarcoma post-hysterectomy. 66-year-old female with uterine adenosarcoma status post hysterectomy, chronic obstructive pulmonary disease, and a 108-pack-year smoking history was found to have multiple small lung nodules on CT. PET imaging revealed no FDG-avid lesions, and a Nodify Lung® blood test assessing autoantibodies associated with bronchogenic tumor antigens returned a low-risk result, decreasing initial suspicion of malignancy. Ten months later, follow-up CT demonstrated significant interval progression, including a 49-mm left lung mass and a 43-mm right lower lobe mass with additional nodules. CT-guided biopsy confirmed SpCC. The patient was referred to oncology for further management. SpCC is a rare and aggressive malignancy that originates in epithelial tissues but demonstrates mesenchymal-like features, complicating diagnosis and treatment. Known for its spindle-shaped cells and metastatic potential, it accounts for a small fraction of lung tumors. Metastasis from distant sites, such as the uterus, is exceptionally rare. Despite initially reassuring findings including non-hypermetabolic PET results and a low-risk Nodify Lung® autoantibody assessment, follow-up imaging demonstrated significant progression, with biopsy confirming SpCC. Limitations of the Nodify Lung® test, which may yield a low-risk result despite the presence of metastatic disease from a non-bronchogenic origin, are also evident in this case. The delayed detection emphasizes the need for close surveillance in patients with prior malignancy and unexplained pulmonary nodules. It highlights the potential for delayed metastasis even after a hysterectomy and the challenges of diagnosing rare metastatic cancers when standard imaging and blood tests do not raise immediate concern. This case represents the first documented instance of pulmonary metastatic SpCC following hysterectomy for uterine adenosarcoma. Clinicians should maintain a broad differential when new or enlarging lung masses arise in patients with prior gynecologic malignancy, even years after definitive treatment. Vigilance remains critical, as rare metastatic pathways may evade conventional screening tools. This abstract is funded by: None
Won et al. (Fri,) studied this question.