[CT, MRI and pathologic features of peripheral primitive neuroectodermal tumors: a report of eight cases with literature review].

BACKGROUND &

OBJECTIVE

Peripheral primitive neuroectodermal tumor (pPNET) is very scarce. This study was to analyze the imaging and pathologic features of pPNET.

METHODS

Computed tomogram (CT) and magnetic resonance image (MRI), and pathologic reports of 8 pPNET patients were analyzed.

RESULTS

Of the 8 cases, 1 lesion located at the maxillary sinus, 1 near to the nose, 1 at the shoulder and neck, 2 in the chest, 2 in the mediastinum, and 1 in the sacrococcygeal gluteus maximus. All lesions were soft tissue masses. CT images revealed that all lesions were huge and inhomogeneous, with unclear border and were accompanied with cystis degeneration. Gravel-like calcifications were detected in some lesions that showed heterogeneous enhancement after contrast. Osteolytic bone destruction was observed when the soft tissue mass invaded the adjacent bones. T1-weighted image showed low or equal signal, and T2-weighted image showed uneven high signal. Some lesions showed false capsule and separating changes. Homer-Wright daisy-group was a specific pathologic feature of pPNETs. According to Immunohistochemical results, CD99 was positive in all lesions, neurone specific enolase (NSE) and vimentin (VIM) were positive in all the 3 detected lesions, cytokeratin (CK) and leucocyte common antigen (LCA) were negative in all the 5 detected lesions.

CONCLUSIONS

The pathologic and immunohistochemical determinations can provide diagnostic references for pPNETs. Although the manifestations of pPNETs on CT and MR images are not specific, these two methods can show the internal structure of tumors and help to define their scope, which are helpful in determining treatment strategy and evaluating therapeutic effects.