Radiological and clinicopathological features of pPNET

To analyze the radiological and clinicopathological features of peripheral primitive neuroectodermal tumor (pPNET).

We retrospectively reviewed the computed tomography (CT) and magnetic resonance (MR) imaging of 14 cases of pPNET confirmed immunohistochemically. Relevant clinical data was also obtained.

Of 14 cases, there were 10 male and 4 female with a mean age of 28 years. The main symptoms were the aggravated pain of the lesion site and enlarged palpable masses. Fourteen lesions were located in the chest wall (n = 4), retroperitoneum (n = 3), pelvic cavity (n = 2), intraspinal area (n = 2), nasal cavity (n = 1), leg ( n= 1) and iliac bone (n = 1). Eleven lesions originating from the soft tissue mainly demonstrated large and infiltrative mass with (n = 4) or without (n = 7) bony invasion. Ten cases of them showed heterogeneous density with patchy, necrotic foci and moderate heterogeneous enhancement. Four of them with large cystic area contained irregular septations within them. Two intraspinal cases had extradural lesions, extending through the intervertebral foramen and formed paraspinal soft tissue masses with vertebral destruction. The case within iliac bone demonstrated extensive mixed (lytic/osteoblastic) lesion with large adjacent soft tissue mass. After surgery or therapy, 10 patients died of local recurrences or metastases.

The diagnosis of pPNET should be suggested in young patient when imaging depicts a large, ill-defined, soft-tissue mass containing area of cystic degeneration with internal septations and extending along the neural route and nearby the middle of the trunk. The key for correct diagnosis is to inosculate imaging to clinical data.