대한흉부영상의학회 Weekly Chest Cases

Case No : 1464 Date 2025-11-10

Courtesy of Won Gi Jeong / Chonnam National University Hwasun Hospital
Age/Sex 80 / M
Chief ComplaintFor restaging of lung cancer. s/p RULopctomy and adjuvant concurrent chemoradiotherapy for mucoepidermoid carcinoma

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Diagnosis With Brief Discussion

Diagnosis: Radiation-induced sarcoma
Radiologic Findings: Figure 1. An axial enhanced CT image shows a heterogeneously enhancing mass with direct invasion of the adjacent chest wall and ribs at the periphery of the right upper lobe.
Figure 2. An axial enhanced CT image for lung cancer restaging shows a heterogeneously enhancing nodular lesion in the right pectoralis minor muscle, seven years after lung cancer treatment.
Figure 3. High FDG uptake is notable within the nodular lesion on the 18F-FDG PET/CT.
Figure 4. A percutaneous ultrasound-guided core needle biopsy was performed for the hypoechoic mass within the right pectoralis minor muscle. The pathological diagnosis was sarcoma.
Figure 5. This lesion is located within the field where radiotherapy was previously administered.
Brief Review: Radiation therapy (RT) is a primary treatment strategy for over half of cancer patients, significantly enhancing survival rates and long-term outcomes across various cancer types. Consequently, the utilization of RT continues to grow. For instance, a Korean study documented a 65% rise in cancer patients receiving RT between 2006 and 2013. However, despite its clear benefits, RT has been linked to the development of a rare iatrogenic malignancy known as "radiation-induced sarcoma" (RIS), accounting for approximately 3% of all soft tissue sarcomas. This condition is associated with poor prognosis, with 5-year overall survival rates ranging from 10% to 36%, depending on the disease stage at diagnosis. As such, RIS poses a significant challenge for physicians and is becoming an increasingly prevalent clinical issue, likely driven by the growing number of long-term cancer survivors achieved through advancements in cancer screening and management strategies.
A comprehensive analysis of the Surveillance, Epidemiology, and End Results (SEER) registries revealed a 257% higher risk of secondary bone sarcoma in patients who underwent RT compared to the general population. More recently, Snow et al. reviewed these findings and reported that breast cancer carries the second-highest risk of RIS after cervical cancer, with rates of 78.3% and 88.2%, respectively. RIS following RT for breast cancer encompasses a diverse range of histopathologic subtypes, with malignant fibrous histiocytoma being the most prevalent. Other, less common types include leiomyosarcoma, liposarcoma, fibrosarcoma, angiosarcoma, and, rarely, chondrosarcoma and osteosarcoma. These secondary RIS are typically high-grade tumors of varying sizes, characterized histologically by spindle-shaped tumor cells, hemorrhagic nodules, abundant mitotic activity, and areas of necrosis.
References: 1. Laurino S, Omer LC, Albano F, Marino G, Bianculli A, Solazzo AP, Sgambato A, Falco G, Russi S, Bochicchio AM. Radiation-induced sarcomas: A single referral cancer center experience and literature review. Front Oncol. 2022 Sep 30;12:986123.
2. Joo MW, Kang YK, Ogura K, Iwata S, Kim JH, Jeong WJ, et al. Post-radiation sarcoma: A study by the Eastern Asian musculoskeletal oncology group. PLoS One (2018) 13:e0204927.
3. Snow A, Ring A, Struycken L, Mack W, Koç M, Lang JE. Incidence of radiation induced sarcoma attributable to radiotherapy in adults: A retrospective cohort study in the SEER cancer registries across 17 primary tumor sites. Cancer Epidemiol (2021) 70:101857.
Keywords

No. of Applicants : 66

▶ Correct Answer : 29/66, 43.9%

- Kyung Hee University Medical Hospital , Korea (South) JEONG TAEK YOON
- Yonsei University,Severance Hospital , Korea (South) SEO BUM CHO
- Saitama-Sekishinkai Hosptal , Japan MIHOKO YAMAZAKI
- university of montreal , Canada Andrei Bogdan Gorgos I
- Kyoto University , Japan SHO KOYASU
- , Sweden MOHAMAD TLASS
- Osaka metropolitan university Hospital , Japan TATSUSHI OURA
- Toyota Kosei Hospital , Japan YUKI HAYASHI
- Kyeongpook National University Hospital , Korea (South) JOHN BAEK
- The University of Tokyo Hospital , Japan TOSHIHIRO FURUTA
- The First Affiliated Hospital of Nanjing Medical University , China TENG ZHANG
- Japanese Red Cross Otsu Hospital , Japan JUN YOSHIDA
- Kyoto University Hospital , Japan YUSUKE UTSUNOMIYA
- Chonnam National University Hospital , Korea (South) SOMIN LEE
- , Korea (South) KYUNG HYUN WOO
- Seoul National University College of Medicine , Korea (South) MINHO LEE
- Fukuoka university , Japan KEISUKE SATO
- McGill University Health Center , Canada ALEXANDRE SEMIONOV
- , Japan HITOSHI TAKEUCHI
- Vita Hospital , Brazil DIOGO LAGO PINHEIRO
- Osaka University , Japan AKINORI HATA
- , Japan YOSHIKI ISHII
- The University of Tokyo Hospital , Japan ISSEI FUKUDA
- , Japan YUMI MAEHARA
- Chonnam National University Hospital , Korea (South) JAEBONG YANG
- Jiangsu province hospital , China WANGJIAN ZHA
- Oita university , Japan NORITAKA KAMEI
- University of Yamanashi , Japan HIROAKI WATANABE
- Ehime University , Japan KOTARO MATSUMOTO

▶ Correct Answer as Differential Diagnosis : 5/66, 7.6%

- University of Yamanashi , Japan HIROYUKI MORISAKA
- University of Yamanashi , Japan KOJIRO ONOHARA
- Aichi Medical University , Japan HIROAKI OKADA
- , Japan KEISUKE OSHIMA
- Secomedic Hospital , Japan FUMINORI MIYOSHI

▶ Semi-Correct Answer : 1/66, 1.5%

- Oita University, Faculty of Medicine , Japan FUMITO OKADA

대한흉부영상의학회 Korean Society of Thoracic Radiology

Archive of Old Cases

Case No : 1464 Date 2025-11-10

Discussion

No. of Applicants : 66