Background: Papillary tumors of the pineal region (PTPRs) are malignant World Health Organization grade II/III tumors; however, they may perfectly mimic benign tumors (e.g., pineocytomas [World Health Organization grade I]).
Case description: We present a case of a 28-year-old man with a 35-mm tumor of the pineal region. Considering the typical radiological and pathologic presentation, the tumor was first diagnosed as pineocytoma. However, despite first total resection, the tumor recurred after 7 years. The recurrent neoplasm was composed mainly of papillary structures with low-grade atypical cells positive for CKAE1/AE3 and CK18. This categorization led to the final diagnosis of PTPR. The patient underwent adjuvant radiotherapy, which vastly improved his neurologic condition and resulted in significant tumor regression.
Conclusions: This case exemplifies that PTPRs can perfectly mimic pineocytomas and simple staining for cytokeratins may warrant correct diagnosis and better treatment.
Keywords: Cytokeratin; PTPR; Papillary tumor of the pineal region; Pathology; Pineocytoma; Radiotherapy.
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