대한흉부영상의학회 Weekly Chest Cases

Case No : 1460 Date 2025-10-13

Courtesy of Sung Goo Park, Ho Yun Lee / Samsung Medical Center
Age/Sex 25 / F
Chief ComplaintIncidentally found abnormality

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Diagnosis With Brief Discussion

Diagnosis: Thymic paraganglioma
Radiologic Findings: Fig. 1 Suspected space-occupying lesion or mass with a mediastinal bulging contour, causing loss of the normal aortopulmonary window silhouette on the PA chest radiograph.
Fig. 2-4 CT scans demonstrate an intensely enhancing soft tissue mass with internal necrotic area and prominently engorged peripheral vascular structures in the mediastinum..
Fig. 5 Post-contrast T1-weighted MR image also demonstrates a large mediastinal mass with strong enhancement.
Fig. 6 T2-weighted MR image shows serpiginous signal voids of internal vessels within the mass.
Brief Review: Paragangliomas are rare neuroendocrine tumors originating from paraganglionic cells of the autonomic nervous system and can occur in various locations, including the mediastinum. Although more commonly identified in the head and neck region or within the abdomen, mediastinal paragangliomas, particularly those arising in relation to the thymus, are extremely rare. When present, these tumors often manifest as hypervascular masses with characteristic imaging features.

In our case, a 25-year-old female patient was found to have an asymptomatic mediastinal mass incidentally detected during a medical examination. A mediastinal mass was suspected on the initial chest radiograph. Subsequent contrast-enhanced chest CT demonstrated an intensely enhancing soft tissue mass with an internal poorly enhancing area and prominently engorged peripheral vascular structures in the anterior mediastinum. On MRI, strong vascular enhancement on post-contrast T1-weighted images and serpiginous signal voids of internal vessels on T2-weighted images were noted. These signal voids correspond to the “pepper” component of the so-called “salt and pepper sign,” a characteristic MRI finding commonly associated with paragangliomas, reflecting the presence of numerous intratumoral vessels with high-velocity blood flow. However, in our case, the intratumoral hemorrhage typically representing the “salt” component (pre-contrast T1 high signal intensity) was not clearly identified.

This combination of imaging findings—intense enhancement reaching vascular enhancement, and the characteristic signal void (pepper component) of the “salt and pepper” appearance on MRI—strongly suggests a paraganglioma arising in the anterior mediastinum, likely a rare thymic paraganglioma. The patient underwent surgical excision of the mediastinal mass, and a 7.8-cm sized thymic paraganglioma was confirmed on final histopathological examination.

Although the MR imaging findings of paragangliomas originating in the head and neck region or within the abdomen are well documented, reports of MR imaging characteristics of thymic paragangliomas, as in our case, are exceedingly rare. This case shows that the MRI features of a rare thymic paraganglioma closely resemble those of more common paragangliomas, thereby adding valuable insight to the limited literature on these uncommon tumors.
References: 1. Lee KY, Oh YW, Noh HJ, et al. Imaging of Paragangliomas in the Head and Neck: CT and MR Findings. AJR Am J Roentgenol. 2006;186(3):797–802.
2. Kim SY, Park JW, Han J, et al. Mediastinal paraganglioma: a case report and review of the literature. Korean J Thorac Cardiovasc Surg. 2012;45(6):390–393.
3. Wanebo HJ, Gannon CJ, Rewcastle NB, Allen NE, Wilhelm W, Phalen E, Clark R, Willcockson G, Mills JL. Primary Mediastinal Paraganglioma: A Case Report and Review of the Literature. Ann Thorac Surg. 2007;83(4):1545–1547.
4. Hiyoshi T, Oka S, Sasaki K, et al. Thymic paraganglioma. Gen Thorac Cardiovasc Surg. 2010;58(7):351–354.
Keywords

No. of Applicants : 75

▶ Correct Answer : 22/75, 29.3%

- McGill University Health Center , Canada ALEXANDRE SEMIONOV
- Kyoto University Hospital , Japan YUSUKE UTSUNOMIYA
- Samsung Medical Center , Korea (South) HYUNGIN PARK
- , France CHARLES DAMIEN
- Vita Hospital , Brazil DIOGO LAGO PINHEIRO
- Kyeongpook National University Hospital , Korea (South) JUNGMIN LEE
- Secomedic Hospital , Japan FUMINORI MIYOSHI
- university of montreal , Canada Andrei Bogdan Gorgos I
- University of Yamanashi , Japan TAKAAKI HASHIMOTO
- University of Yamanashi , Japan HIROYUKI MORISAKA
- The University of Tokyo Hospital , Japan TOSHIHIRO FURUTA
- , Japan YOSHIKI ISHII
- University of Yamanashi , Japan HIROAKI WATANABE
- Jichi Medical University, School of Medicine , Japan MITSURU MATSUKI
- Shiga General Hospital , Japan YUSAKU MORIBATA
- Osaka metropolitan university Hospital , Japan TATSUSHI OURA
- Dokkyo Medical University , Japan HIROAKI ARAKAWA
- Fukuoka university , Japan KEISUKE SATO
- Matsunami General Hospital , Japan TARO TAKEDA
- Nara medical university , Japan HIROHIDE WATANABE
- Toyota Kosei Hospital , Japan YUKI HAYASHI
- University of Yamanashi , Japan KOJIRO ONOHARA

▶ Correct Answer as Differential Diagnosis : 12/75, 16.0%

- Saitama-Sekishinkai Hosptal , Japan MIHOKO YAMAZAKI
- medical scanning , Japan HIROAKI ARAKAWA
- Kyoto University , Japan AKIHIKO SAKATA
- Oita university , Japan AYUMI KAMEI
- Osaka University , Japan AKINORI HATA
- Japanese Red Cross Otsu Hospital , Japan JUN YOSHIDA
- University of Tsukuba, Dept of Radiology , Japan MANABU MINAMI
- , Japan MATSUNO MAI
- Kyoto University , Japan SHO KOYASU
- Yonsei University,Severance Hospital , Korea (South) SEO BUM CHO
- Kantou Rousai Hospital , Japan KAORU SUMIDA
- , Sweden MOHAMAD TLASS

대한흉부영상의학회 Korean Society of Thoracic Radiology

Archive of Old Cases

Case No : 1460 Date 2025-10-13

Discussion

No. of Applicants : 75