대한흉부영상의학회 Weekly Chest Cases

Case No : 1401 Date 2024-08-26

Courtesy of Youkyung Lee / Hanyang University Guri Hospital
Age/Sex 74 / M
Chief ComplaintAbnormal chest X ray

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Diagnosis With Brief Discussion

Diagnosis: Solitary fibrous tumor of the pleura
Radiologic Findings: The PA (Fig.1) and lateral (Fig.2) chest radiographs show a mass in the right posterior mediastinum in close contact with the adjacent rib heads and vertebrae. The mass is 8.2 cm in size and shows heterogeneous enhancement on contrast-enhanced CT in the axial (Fig. 4) and coronal (Fig. 5) views. The adjacent rib shows mild hypertrophy. On MRI, the mass had no neural foramen or spinal canal involvement. (T2 fat sat Fig 6,7,8)
Brief Review: The tumor was resected. The tumor was surrounded by serous membrane and attached to the heads of the right 5th, 6th ribs. There was strong adhesion to the parietal pleura and ribs. Bleeding prevented the resection of a small portion of the tumor with fibrotic tissue.

The pathologic diagnosis was solitary fibrous tumor, low risk (total score 2/7: patient age>55 (score 1/1), tumor size (score 1/3), mitosis (score 0), tumor necrosis (score 0))

Solitary fibrous tumour (SFT) is a fibroblastic neoplasm with a characteristic histologic appearance, immunohistochemical profile, and NAB2-STAT6 gene rearrangement.
Most intrathoracic SFTs arise from the visceral pleura, but they may occur at any site, including within the lung parenchyma and pericardium. They rarely occur in the mediastinum.
SFTs are macroscopically well-circumscribed, solid, tan to grey homogeneous masses, frequently pedunculated and often large (>100mm). Cystic necrosis, haemorrhage, and calcification are occasionally present. In 3% of cases, no pleural attachment can be identified, and the tumour is surrounded by lung parenchyma. Tumours are uncommonly found to involve the pericardium.
On histopathology, SFTs have a distinctive morphology, with uniform fibroblastic spindle cells, varying cellularity, a patternless architecture, fibrosis, and branching staghorn vessels. There is a wide histopathological spectrum, ranging from paucicellular lesions with abundant stromal keloidal-type collagen to highly cellular tumours consisting of closely spaced cells with little or no intervening stroma. Myxoid change may be present.
By immunohistochemistry, SFTs are typically positive for CD34 and nuclear STAT6. Expression may be lost in dedifferentiated SFTs.
Most SFTs have low mitotic counts and show little nuclear pleomorphism. The presence of mitotic figures (greater than 10 per high power field), necrosis, infiltrative growth pattern and large size is associated with aggressive (malignant) behavior. Age above 55 years is also a risk factor.

Most SFTs grow slowly and form large masses, which could be asymptomatic or cause variable compression symptoms depending on the tumor size and location. Large SFTs are associated with paraneoplastic syndromes. Secretion of insulin-like growth factor 2 by the neoplastic cells may result in refractory hypoglycemia (Doege-Potter syndrome). More rarely, IGF2 production can produce an acromegaly-like syndrome. Thoracic lesions may be associated with hypertrophic osteoarthropathy.

Local or distant recurrence of SFTs has been documented in about 10
References
Keywords

No. of Applicants : 60

▶ Correct Answer : 8/60, 13.3%

- Other , Korea (South) SEONGSU KANG
- university of montreal , Canada Andrei Bogdan Gorgos I
- Other , Korea (South) HYEJOO PARK
- Other , Korea (South) CHAEHUN LIM
- Osaka metropolitan university Hospital , Japan TATSUSHI OURA
- Dokkyo Medical University , Japan HIROAKI ARAKAWA
- Juntendo University , Japan YUTAKA IKENOUCHI
- Jiangsu province hospital , China WANGJIAN ZHA

▶ Correct Answer as Differential Diagnosis : 18/60, 30.0%

- ZIGONG TCM HOSPITAL OF CHINA , China CAO CUN YOU
- , Korea (South) DONG-HO BANG
- the First Affiliated Hospital of NanJing Medical University , China AIPING CHEN
- Healthy Longevity Medical Center , Japan SHIN-ICHI CHO
- Vita Hospital , Brazil DIOGO LAGO PINHEIRO
- Oita University, Faculty of Medicine , Japan FUMITO OKADA
- The University of Tokyo Hospital , Japan TOSHIHIRO FURUTA
- Narayana Multispeciality Hospital Jaipur Rajasthan , India JAINENDRA JAIN
- Nankai medical center , Japan NORITAKA KAMEI
- , Japan KENTARO KOTANI
- , Japan SHUNJIRO NOGUCHI
- University of Tsukuba, Dept of Radiology , Japan MANABU MINAMI
- Mie university , Japan SHIKO OKABE
- Other , Korea (South) SEOL A LEE
- Kyoto University , Japan SHO KOYASU
- Yonsei University,Severance Hospital , Korea (South) SEO BUM CHO
- , Japan YUMI MAEHARA
- Toyota Kosei Hospital , Japan YUKI HAYASHI

대한흉부영상의학회 Korean Society of Thoracic Radiology

Archive of Old Cases

Case No : 1401 Date 2024-08-26

Discussion

No. of Applicants : 60