A 72-yr old female visited a local hospital complaining of left lower abdominal discomfort and constipation. An abdominal computed tomography (CT) confirmed a retroperitoneal tumor and the patient was referred to our hospital for further examination. Magnetic resonance imaging (MRI) of the abdomen showed a solid mass measuring 13 cm in diameter on the left side of the pelvis and a liposarcoma containing a well-differentiated component was diagnosed (Fig. 1A). A high-resolution computed tomography (HRCT) of the abdomen revealed that the tumor was suspected to invade the left ureter and descending colon (Fig. 1B). Moreover, HRCT of the chest detected two ground-glass opacities (GGO) in the apical segment (S1) and posterior segment (S2) of the right upper lobe of the lung and was considered to be early stage lung cancer (Fig. 2A). Treatment was carried out by retroperitoneal liposarcoma and retroperitoneal tumor resection after ureteral stent placement by urologists. Intraoperative findings showed that the tumor displaced the descending colon which was therefore partially resected. The tumor size was 13 x 8 x 7.5 cm and postoperative pathological findings indicated DDLPS with invasion to the sigmoid colon (Fig. 1C, D). Four months after the retroperitoneal liposarcoma resection, a right upper lobectomy for suspected lung cancer was performed via video-assisted thoracoscopic surgery (VATS) (Fig. 2B).
After lung cancer surgery, the patient was followed-up as an outpatient. Twenty months after the initial surgery, a HRCT of the chest detected a tumor with maximum diameter of 22 mm in the left lower lobe of the lung (Fig. 3A). Because the tumor was located in the peripheral lung, CT-guided fine needle biopsy was performed rather than transbronchial bronchial lung biopsy (TBLB). Pathological findings indicated pulmonary metastasis from dedifferentiated liposarcoma and the tumor tended to grow rapidly. The result of a respiratory function test on the patient showed that her current respiratory function was not sufficient to allow a left lower lobectomy, therefore, in order to preserve the superior segment of the lower lobe (S6), a left basal segmentectomy (S8+S9+S10) was conducted (Fig. 3B). Pathological findings showted DDLPS with invasion to the sigmoid colon (Fig. 3C). The postoperative course was uneventful and she was discharged on the 16th day after the operation. There is no sign of recurrence of the tumor seven months after discharge. She is undergoing outpatient rehabilitation, and she is able to live an independent life without home oxygen therapy.