Klin Onkol 2025; 38(3): 213-217. DOI: 10.48095/ccko2025213.
Background: Treatment of patients with malignant undifferentiated lung tumors who also have diffuse lung disease is difficult, especially when the tumor grows rapidly. Herein we present a malignant undifferentiated tumor of the lung with rapid growth. Case: A 57-year-old man was diagnosed with chronic obstructive pulmonary disease and was receiving inhalation of long-acting muscarinic antagonist / long-acting beta2 agonist. At the age of 65, dyspnea became worse and he had hemoptysis. A chest radiograph revealed an 11 × 9 mm nodule in the right upper lung field. This nodule grew to 89 × 60 mm and 102 × 68 mm on radiographs taken 63 and 79 days after the date of the first radiograph. The volume doubling times were 7 and 23 days, respectively, and it was a rapidly growing, highly malignant tumor. The tissue specimens obtained by percutaneous biopsy from this lesion was pathologically diagnosed as malignant undifferentiated tumor of the lung. Chemotherapy including immune checkpoint inhibitors was effective. Although the patient still has cancer, he is constantly undergoing treatment 2.5 years after its initiation. Conclusion: It is interesting to note that the course of the rapidly growing lung tumor and the effectiveness of chemotherapy including immune checkpoint inhibitors in patients with such a rapid growth. We believe that information about the clinical course of this patient may provide insight into the treatment of future patients who may have a similar clinical course.