The clinicopathological features of intermediate trophoblastic tumor in the pineal region

Abstract

Objective To evaluate the clinicopathological features of intermediate trophoblastic tumor (ITT) in the pineal region. Methods A retrospective study was performed to analyse the diagnostic and therapeutic process of 1 case with ITT in the pineal region. The specimen obtained from the surgery was dealt with common tissue processing mode and cut into slices. HE staining was performed to observe histophathological features. Immunohistochemical staining (SP two⁃step method) was performed to analyse the expression of tumor markers. Related literatures were reviewed. Results A 6 ⁃ year old boy with clinical manifestations of penis enlargement and rapid growth for more than one year, presented a mass in his pineal region through MRI. The tumor was surgically excised after it is refractory to 10 times experimental radiotherapy as germinoma. The level of β ⁃ human chorionic gonadotropin ( β ⁃ hCG) in his postoperative blood was decreased to normal, but gradually increased, once again followed to normal after three times chemotherapy. Patient was normal almost postoperative 6 months later by follow ⁃ up. Pathological examination showed sheets necrosis with multiple calcification and scattered fresh blood cells, epithelioid tumor cells with solid growth pattern. The tumor cells were atypical mononuclear cells with relative uniform (between heterotypic cells) and partially surrounding and invasing the vascular walls. The cytoplasm of tumor cells was eosinophilic or clear, the nucleus was round or irregular in shape and some with intranuclear pseudoinclusions, and its mitotic figures were rarely seen under light microscopy. The tumor cells showed strong positive for AE1/AE3, cell adhesion molecules 5.2 (CAM5.2), human placental lactogen (hPL), octamer⁃binding transcription factor 3/4 (Oct3/4), epidermal growth factor receptor (EGFR) and E⁃cadherin. P53 was also expressed. The positive rate of Ki⁃67 was about 10%, and β⁃hCG was expressed in the extremely tumor cells. The tumor cells were negative for placental alkaline phosphatase (PLAP), alpha⁃feto protein (AFP), CD30 (Ki⁃1) and P63. Conclusion ITT in pineal region is very rare, and has partial morphological characteristics of placental site trophoblastic tumors (PSTT) and epithelioid trophoblastic tumors (ETT). This case got a good control through radiotherapy, operation excision combined with chemotherapy.

DOI：10.3969/j.issn.1672⁃6731.2012.04.017