title: Imaging findings of adrenal primitive neuroectodermal tumors: a series of seven cases.
abstract: OBJECTIVE
  To explore the imaging features of adrenal primitive neuroectodermal tumors (PNETs).
  
  
  METHODS
  This retrospective study included seven patients with surgically and pathologically confirmed adrenal PNETs. Among them, six underwent computed tomography (CT) scans, and one underwent magnetic resonance imaging. The imaging findings, including size, shape, margin, hemorrhage, calcification, cystic degeneration, regional lymph nodes involvement, tumor thrombus formation and enhancement pattern, were retrospectively analyzed.
  
  
  RESULTS
  Among the seven adrenal PNET patients, six were male, and one was female. The median age was 26 years (range 2-56 years). The disease generally presented with either insidious symptoms (n = 4) or non-specific symptoms, including right flank pain (n = 1) and left upper abdominal discomfort (n = 2). On the pre-enhanced CT images, the tumor usually appeared as a well-defined, rounded or oval, heterogeneous mass without calcification. Certain tissue characteristics, such as cystic degeneration (n = 5), capsule (n = 4) and hemorrhage (n = 2), were observed. Regional lymph node involvement was observed in three cases, and renal vein thrombus was observed in one case. All cases showed mild heterogeneous enhancement of the tumor on the enhanced CT images.
  
  
  CONCLUSIONS
  An adrenal PNET commonly presents as a relatively large, well-defined, heterogeneous mass with cystic degeneration, necrosis and a characteristic mild contrast-enhancement pattern on multiphase enhanced images. PNET should be considered when the diagnosis of common tumors is not favored by signs on images.
  This study was approved by the medical ethics committee of Xiangya Hospital, Central South University. The approval number is 201512538.
authors.affiliation: Department of Radiology, Xiangya Hospital, Central South University, 87# XiangYa Road, Changsha, 410008, Hunan, People's Republic of China.
authors.forename: Y
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Imaging Diagnosis and Interventional Center, Sun Yat-sen University Cancer Center, Guangzhou, People's Republic of China.
authors.forename: P
authors.initials: P
authors.lastname: Cai
authors.affiliation: Department of Ultrasonography, Xiangya Hospital, Central South University, Hunan, People's Republic of China.
authors.forename: M
authors.initials: M
authors.lastname: Chen
authors.affiliation: Department of Radiology, Xiangya Hospital, Central South University, 87# XiangYa Road, Changsha, 410008, Hunan, People's Republic of China. doctoryixiaoping@126.com.
authors.forename: X
authors.initials: X
authors.lastname: Yi
authors.affiliation: Imaging Diagnosis and Interventional Center, Sun Yat-sen University Cancer Center, Guangzhou, People's Republic of China.
authors.forename: L
authors.initials: L
authors.lastname: Li
authors.affiliation: Department of Pathology, Xiangya Hospital, Central South University, Hunan, People's Republic of China.
authors.forename: D
authors.initials: D
authors.lastname: Xiao
authors.affiliation: Department of Radiology, Xiangya Hospital, Central South University, 87# XiangYa Road, Changsha, 410008, Hunan, People's Republic of China.
authors.forename: W
authors.initials: W
authors.lastname: Liu
authors.affiliation: Department of Radiology, Xiangya Hospital, Central South University, 87# XiangYa Road, Changsha, 410008, Hunan, People's Republic of China.
authors.forename: W
authors.initials: W
authors.lastname: Li
authors.affiliation: Departments of General Surgery, Xiangya Hospital, Central South University, Hunan, People's Republic of China.
authors.forename: Y
authors.initials: Y
authors.lastname: Li
mesh_terms: D000293:Adolescent; D000310:Adrenal Gland Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology*; D000328:Adult; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D018241:Neuroectodermal Tumors, Primitive, Peripheral / Q000000981:diagnostic imaging* / Q000473:pathology*; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed; D055815:Young Adult
keywords: Adrenal tumors; Computed tomography (CT); Diagnosis; Magnetic resonance imaging (MRI); Primitive neuroectodermal tumors (PNETs)