Primary intracranial peripheral primitive neuroectodermal tumor in an adult patient with aphasia: A rare case report

Abstract

Primary intracranial peripheral primitive neuroectodermal tumors (pPNETs) are extremely rare malignancies that commonly affect children and adolescents. Only 10 cases over the age of 33 have been reported. pPNETs have an aggressive behavior and a high tendency for local recurrence and distant metastasis. Here, we present a case of supratentorial pPNET that affected the left frontoparietal lobe of a 36‐year‐old female patient. The patient complained of aphasia during the last 2 months. Aphasia is reported for the first time as a result of a pPNET. In T1‐weighted MRI, a large mass with mixed isointense to hypointense signals was observed. The tumor was completely removed. Histopathologic examination was indicative of a small round cell tumor. Immunohistochemical analysis showed positivity for CD99. Presence of EWSR1 gene rearrangement confirmed the diagnosis. The patient's aphasia was gradually resolved post‐surgery. Six months follow‐up showed no evidence of local recurrence or metastasis.

Primary intracranial peripheral primitive neuroectodermal tumor: lessons from an exceptionally rare neoplasm. Illustrative case

“… 2 Additionally, histopathological examination of pPNET specimens often reveals small, round, darkly stained cells with hyperchromatic nuclei and a high mitosis rate. 20 , 21 This microscopic similarity is shared with other malignant pathologies such as anaplastic ependymoma, atypical teratoid/rhabdoid tumor, lymphoma, rhabdomyosarcoma, malignant meningioma, and other forms of highly proliferative malignant neuroectodermal tumors. 5 , 20 , 22 Given this broad differential diagnosis, the final diagnosis of pPNET requires an extensive workup, including immunohistochemistry analysis and cytogenetic examination.…”

“… 20 , 21 This microscopic similarity is shared with other malignant pathologies such as anaplastic ependymoma, atypical teratoid/rhabdoid tumor, lymphoma, rhabdomyosarcoma, malignant meningioma, and other forms of highly proliferative malignant neuroectodermal tumors. 5 , 20 , 22 Given this broad differential diagnosis, the final diagnosis of pPNET requires an extensive workup, including immunohistochemistry analysis and cytogenetic examination. Immunohistochemistry analysis shows positive expression of CD99, FLI-1, NKX2.2, GFAP, and synaptophysin and negative EMA expression.…”

“… 5 , 8–12 Besides, it is worth mentioning that central nervous system embryonal tumors are negative for CD99 and EWSR1 gene rearrangement, which helps to distinguish them from pPNET. 20 …”

“…In particular, CD99 is a highly sensitivity but nonspecific marker. 20 Conversely, detection of the EWSR1 gene, stemming from the translocation t(11;22)(q24;q12), can be regarded as more specific and confirmatory. 5,[8][9][10][11][12] Besides, it is worth mentioning that central nervous system embryonal tumors are negative for CD99 and EWSR1 gene rearrangement, which helps to distinguish them from pPNET.…”

“…5,[8][9][10][11][12] Besides, it is worth mentioning that central nervous system embryonal tumors are negative for CD99 and EWSR1 gene rearrangement, which helps to distinguish them from pPNET. 20 Although no consensus exists about the optimal therapy for pPNETs, treatment options include resection, chemotherapy, and radiotherapy. Gross-total resection (GTR) is regarded as the cornerstone of therapy and impacts survival rates.…”