대한흉부영상의학회 Weekly Chest Cases

Case No : 1449 Date 2025-07-28

Courtesy of Yeon Joo Jeong, / Pusan National University Yangsan Hospital
Age/Sex 73 / M
Chief ComplaintBrown urine, incidentally detected abnormality on chest CT for genitourinary disease work-up

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Diagnosis With Brief Discussion

Diagnosis: IgG4-Related Disease
Radiologic Findings: Figs 1-3. Lung window images of contrast-enhanced chest CT scans show multiple irregular shaped subpleural lung nodules in both lungs, along with subpleural patchy ground glass opacities in both lower lobes.
Figs 4 and 5. Mediastinal window images of contrast-enhanced chest CT scans show mildly enlarged upper paratracheal and right hilar lymph nodes.
Brief Review: Upper abdominal CT revealed a diffusely enlarged pancreas with peripancreatic fluid, suggestive of pancreatitis. Considering both chest and upper abdominal CT findings, IgG4-related disease (IgG4-RD) was highly suspected. The patient's serum IgG4 level was elevated to 1234 mg/dL (normal range: 3.9–86.4 mg/dL). Histopathologic examination of an ampulla of Vater biopsy demonstrated significant lymphoplasmacytic infiltration, a moderate number of eosinophils, and phlebitis. Immunohistochemistry revealed plasma cell infiltration, with an IgG4-positive to IgG-positive plasma cell ratio greater than 40%. Lung lesions and pancreatitis improved with glucocorticoid therapy.
IgG4-related disease is an immune-mediated fibroinflammatory condition characterized by dense lymphoplasmacytic infiltrates rich in IgG4-positive plasma cells, typically accompanied by storiform fibrosis, obliterative phlebitis, and elevated serum IgG4 levels. It can affect virtually any organ. Thoracic involvement occurs in approximately 40% of IgG4-RD cases and is part of a systemic, multi-organ presentation that may include the pancreas, salivary glands, bile ducts, and kidneys.
Thoracic manifestations of IgG4-RD are diverse and heterogeneous, often mimicking lung cancer, malignant lymphoma, infection, sarcoidosis, or other systemic autoimmune diseases, which may delay diagnosis. The most common radiologic findings in thoracic IgG4-RD are mediastinal lymphadenopathy (50–80%) and peribronchovascular interstitial thickening (60%). Pulmonary manifestations vary and may include peribronchovascular interstitial thickening, nodules or masses, ground-glass opacities, interstitial lung abnormalities, segmental or lobar consolidation, and cavities or cysts.
Treatment is recommended for all symptomatic patients. Immunosuppressive therapy is the mainstay of treatment, with corticosteroids as the first-line option. Steroid non-responsiveness is rare (<5%), but relapse after tapering is common (60–80%). In steroid-refractory cases, other immunosuppressants such as rituximab, azathioprine, or mycophenolate mofetil may be considered. For localized disease, such as a pulmonary nodule or inflammatory pseudotumor, surgical excision may be an option.
References: 1. Stone JH et al. IgG4-related disease. N Engl J Med. 2012;366:539-551.
2. Muller R et al. Thoracic manifestations of IgG4-related disease. Respirology 2023; 28:120-131
Keywords

No. of Applicants : 66

▶ Correct Answer : 9/66, 13.6%

- medical scanning , Japan HIROAKI ARAKAWA
- Shiga University of Medical Science , Japan AKITOSHI INOUE
- Teikyo University Hospital , Japan CHIAKI SATO
- , Korea (South) DAWON PARK
- Korea University Anam Hospital , Korea (South) KYU-CHONG LEE
- Seoul National University Bundang Hospital , Korea (South) YOONAH DO
- Kyung Hee University Medical Hospital , Korea (South) JEONG TAEK YOON
- CHA University, CHA Bundang Medical Center , Korea (South) HWANGSEON JU
- Kantou Rousai Hospital , Japan KAORU SUMIDA

▶ Correct Answer as Differential Diagnosis : 18/66, 27.3%

- Saitama-Sekishinkai Hosptal , Japan MIHOKO YAMAZAKI
- , Japan SUZUNE TSUKAMOTO
- ZIGONG TCM HOSPITAL OF CHINA , China CAO CUN YOU
- Kyoto University , Japan AKIHIKO SAKATA
- , Italy PAOLO BALDASSARI
- Healthy Longevity Medical Center , Japan SHIN-ICHI CHO
- Oita University, Faculty of Medicine , Japan FUMITO OKADA
- Osaka University , Japan AKINORI HATA
- The University of Tokyo Hospital , Japan TOSHIHIRO FURUTA
- Osaka metropolitan university Hospital , Japan TATSUSHI OURA
- Kyoto University , Japan SHO KOYASU
- Kobe Children , Japan SHUHEI NORIMOTO
- Yonsei University,Severance Hospital , Korea (South) SEO BUM CHO
- Fukuoka university , Japan KEISUKE SATO
- Ehime University , Japan TOMOHISA OKADA
- Toyota Kosei Hospital , Japan YUKI HAYASHI
- , Japan JUN YOSHIDA
- Jiangsu province hospital , China WANGJIAN ZHA

대한흉부영상의학회 Korean Society of Thoracic Radiology

Archive of Old Cases

Case No : 1449 Date 2025-07-28

Discussion

No. of Applicants : 66