Spontaneous contrast enhancement fluctuation in adult pilocytic astrocytoma

Radiologia Pub Date : 2026-01-01 Epub Date: 2025-12-24 DOI:10.1016/j.rxeng.2025.101658

S.R.K. Ong , T.J. Rohringer , A.F. Gao , A.E. Para , S. Hiremath , P. Alcaide-Leon

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Abstract

Background

Follow-up imaging is crucial in managing primary brain tumors, with changes in contrast enhancement often used as a marker of tumor activity. However, fluctuations of enhancement independent of tumor progression have been described in low grade tumors in the paediatric population. This study aims to characterize the phenomenon of spontaneous contrast enhancement fluctuations in pilocytic astrocytoma and other low-grade primary brain tumors in the adult population.

Methods

A retrospective review of our MRI database (2011–2021) identified cases of pilocytic astrocytomas, pilomyxoid astrocytoma and rosette-forming glioneuronal tumors with stable tumor size with enhancement changes in clinically stable adult patients off medical treatment. After excluding those without serial MRIs, we reviewed the MRIs and clinical records of 238 patients. Number of cases with enhancement fluctuations, mean duration of increasing enhancement prior to stability or decline and number of fluctuation cycles were recorded.

Results

The cohort included 9 adult patients, 6 pilocytic astrocytomas, 1 pilomyxoid astrocytoma and 2 rosette-forming glioneuronal tumors. Four of these were unresected (44%), while five were residual or recurrent tumors (56%). Despite stable tumor size and clinical status, a variety of enhancement patterns over time were observed: 44% of cases (4/9) demonstrated new or increasing enhancement on follow-up, with subsequent regression of enhancement over a 1−4 year follow-up period. An additional 44% of cases (4/9) displayed cyclical increasing and decreasing enhancement over a longer 7−15 year follow-up period. Mean duration of increasing enhancement prior to stability or decline was 12.3 months (SD 7.1). One case exhibited complete spontaneous resolution of enhancement. Fluctuation in morphology of enhancement was also observed in 44% of cases (4/9).

Conclusions

This is the first study to describe spontaneous fluctuation of enhancement in pilocytic astrocytoma and other circumscribed low-grade brain tumors in an adult population. Awareness of this phenomenon is crucial to prevent misinterpretation of enhancement changes as evidence of tumor progression or regression in clinically stable patients, circumventing unnecessary treatment changes and interventions.

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成人毛细胞星形细胞瘤的自发造影剂增强波动

随访影像在原发性脑肿瘤的治疗中至关重要，对比度增强的变化通常被用作肿瘤活动的标志。然而，在小儿低级别肿瘤中，增强的波动与肿瘤进展无关。本研究旨在描述成人毛细胞星形细胞瘤和其他低级别原发性脑肿瘤的自发造影剂增强波动现象。方法回顾性分析我院MRI数据库（2011-2021年），在临床稳定的成人患者中发现肿瘤大小稳定且增强变化的毛细胞星形细胞瘤、毛粘液样星形细胞瘤和玫瑰花形胶质细胞肿瘤。在排除那些没有连续mri的患者后，我们回顾了238例患者的mri和临床记录。记录有增强波动的病例数、增强在稳定或下降之前的平均持续时间以及波动周期数。结果9例成人患者中6例为毛细胞星形细胞瘤，1例为毛细胞样星形细胞瘤，2例为玫瑰花状胶质细胞瘤。其中4例未切除（44%），5例为残留或复发肿瘤（56%）。尽管肿瘤大小和临床状态稳定，但随着时间的推移，观察到各种强化模式：44%的病例（4/9）在随访中表现出新的或增强的强化，随后在1−4 年 随访期间出现强化消退。另外44%的病例（4/9）在较长的7−15 年 随访期间表现出周期性的增加和减少增强。在稳定或下降之前，增强的平均持续时间为12.3个月（SD 7.1）。1例表现出完全自发的增强消退。44%的病例（4/9）也观察到增强形态的波动。结论：这是第一个描述成人毛细胞星形细胞瘤和其他局限性低级别脑肿瘤增强的自发波动的研究。意识到这一现象对于防止将增强变化误解为临床稳定患者肿瘤进展或消退的证据，避免不必要的治疗改变和干预至关重要。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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Radiologia

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