Case Of pPNET Research Articles

Primary extraskeletal peripheral primitive neuroectodermal tumor of subcutaneous tissue neck in a young adult: A rare case report

Primitive neuroectodermal tumors (PNETs) are poorly differentiated small round cell neoplasms which primarily affect childhood age and very rarely seen in adults. Peripheral PNET (pPNET) cases are very rare compared to central PNET, and most of them originate from neural crest cells located outside the central nervous system. We report a case of large extraosseous pPNET arising from subcutaneous tissue of left side neck in a young male patient. Despite aggressive inherent nature of histology, structural complexity of neck area and poor predictors like tumor size >6 cm, extraosseous nature, this case advocate that complete resolution is possible with aggressive multimodal treatment including surgery, radiation therapy, and chemotherapy. Other major concerns in such cases of pPNET are difficulty in diagnosis due to low incidence, unpredictable site involvement, histological similarity with other round cell tumors and lack of established treatment guidelines.

Peripheral primitive neuroectodermal tumor of the parotid gland in a child: A case report.

Primitive neuroectodermal tumor (PNET) is a term used to describe a group of highly malignant neoplasms of soft-tissue origin, with varying degrees of divergent differentiation. The occurrence of peripheral PNET in the head and neck region has been reported infrequently in the medical literature. This disease generally occurs in adolescents and young adults, and rarely occurs in children <3 years old. The current study presents an extremely rare case of pPNET of the parotid gland in a 2-year-old male, which had been previously misdiagnosed and treated as a mumps. The lesion showed the characteristic histological features of pleomorphic cellular infiltrate with hyperchromatic small cells scattered in the fibrovascular stroma, interposed by fibrous septa and Homer-Wright rosettes. Positive immunohistochemical staining for CD99 and vimentin was detected. The patient was treated with chemotherapy and radiotherapy following surgical removal, and has been under close observation since the treatment (approximately seven months), with no signs of recurrence. The clinical history and radiological and histopathological findings are presented, together with the immunoreactivity of this tumor.

Peripheral primitive neuroectodermal tumour of the left maxillary sinus

Peripheral primitive neuroectodermal tumours (pPNETs) are highly malignant, small-cell neoplasms found mainly in children and young adults. Recent advances in immunohistochemistry and genetic typing have led to reports of a close relationship between pPNET and the previously difficult-to-classify Ewing's sarcoma. We report a case of pPNET involving the left maxillary sinus in a 23-year-old female who presented with a 2-month history of unilateral left-sided nasal obstruction, rhinorrhoea and recurrent bloody nasal discharge. A CT scan of the paranasal sinuses showed a large mass (10 x 7 x 3 cm3) arising from the left maxillary sinus, with signs of bone destruction and invasion of the left orbital floor and pterygomaxillary fossa. MRI revealed a heterogeneous hyperintense signal on a T2-weighted image in the left maxillary sinus. The tumour was surgically removed by means of external lateral rhinotomy. Pathological examination showed a sheet of small cells with irregular nuclei. Immunohistochemical studies demonstrated positive immunoreactivity for neurone-specific enolase, synaptophysin, chromogranin, vimentin, S-100 protein and p30-32 MIC-2 gene product. The patient was treated with chemotherapy consisting of cyclophosphamide, vincristine, adriamycin and actinomycin D, together with radiotherapy to a total tumour dose of 60 Gy. After 59 months of follow-up, the patient remained free of disease and a repeat MRI scan was normalized, with no sign of residual tumour.