Objective:

To investigate the clinicopathological and imaging features of peripheral primitive neuroectodermal t

umors (pPNET) in children

then to improve the recognization of this rare disease and the level of imaging diagnosis.

Methods:

The clinicopathological and imaging findings of 27 patients confirmed with pPNET by pathology were reviewed retrospectively. The differences of clinicopathological and imaging characteristics between patients with different pPNET origins were analyzed.

Results:

Of 27 pPNET patients

12 cases originated from bone tissue

including 3 cases of centrum

3 cases of limbs

2 cases of ilium

each one case of mandible

temporal bone

cheekbone and orbit; 15 cases originated from soft tissue

including 3 cases of abdominal pelvic cavity

3 cases of kidney

3 cases of chest

2 cases of lower limb muscle space and each one case of adrenal gland

pancreas

parotid gland and neck. Compared with the lesions originating from bone in our study

the lesions originating from soft tissue were larger in size (7.9

vs

4.2

P

＜0.001)

higher positive rate of Syn (80.0%

vs

25.0%

P

=0.007) and higher metastatic rate of lymph node (5

vs

0

P

=0.047). On plain computed tomography (CT) images

91.7% lesions showed heterogeneous hypo-dense mass and osteolytic destruction combined if lesions originating from the bone

and calcifications were found in 4 lesionsoriginating from soft tissue. All lesions enhanced heterogeneously with varying areas of cystic changes. Patients with pPNET originating from the bone were more likely to have indistinct borderline than lesions originating from soft tissue (100.0%

vs

58.3%

P

=0.037) on plain images. Preoperative magnetic resonance imaging (MRI) of 9 patients with pPNET originating from bone showed osteolytic bone destruction and irregular soft tissue mass

with equal or low signal on T1-weighted imaging (T1WI)

heterogeneous high signal on T2-weighted imaging (T2WI) and heterogeneous enhancement after contrast injection.

Conclusion:

pPNET in children can involv

e any part of the body

and a large

ill-defined

aggressive soft tissue mass and heterogeneous enhancement with or without osteolytic destruction on CT/MRI images could suggest the diagnosis.