April 15, 2021
Spindle cell oncocytoma (SCO) of the pituitary gland is a rare posterior pituitary neoplasm. Although classified as a grade 1 tumor, it has clinically aggressive features, including hypervascularity and tenacious recurrence. An optimal treatment strategy has yet to be elucidated.
X 光片体征
X 光片体征
一位纺锤形嗜酸细胞瘤患者的术前图像显示了癌症的特殊特征。垂体腺向前移位（如箭头所示）。肿瘤内有许多曲线状的对比增强信号，表明肿瘤内的血管（如星号所示）。垂体柄比平常更水平地移位（如虚线所示）。
肿瘤内点状低信号
肿瘤内点状低信号
T2 加权图像显示肿瘤内的点状低信号（如箭头所示）。
瘤内血流信号
瘤内血流信号
在磁共振血管造影术的影像中可以看到瘤内血流信号（如箭头所示）。
Based on a review of 85 cases, Mayo Clinic neurosurgical researchers have identified clinical, radiographic and pathological features of SCO. The study, published in World Neurosurgery in 2021, also describes possible treatment strategies.
SCO is challenging to diagnose preoperatively, due to its radiographic resemblance to other pituitary tumors. The Mayo Clinic study found that severe hyponatremia — with its associated fatigue, nausea and emesis — may be present in individuals with SCO. A highly vascular, posteriorly placed tumor that displaces the pituitary gland or stalk antero-superiorly might also indicate SCO.
Surgery is complicated by tumor location and by the tumor's hypervascular, fibrous and adhesive nature. SCO is frequently located behind the anterior lobe. Cavernous sinus extension is common. The researchers found many cases in which heavy intraoperative bleeding resulted in incomplete resection or massive blood loss or both.
Among the SCO cases studied, gross total resection (GTR) was achieved in only 24% of patients. The tumor control rate five years after treatment was 75% when GTR was achieved, compared with 24% after non-GTR.
The researchers note that radiotherapy might help decrease tumor progression: Patients who had radiotherapy following non-GTR had a tumor control rate of 76% after five years. However, if GTR isn't achieved and radiotherapy isn't performed, 50% of tumors show significant progression and require further treatment within about two years. Multiple recurrences happen in 20% of these patients, and even distant metastasis is possible.
The researchers further note that long-term follow-up is needed for all patients and that the rate of progression raises questions about the SCO's classification as a grade 1 tumor.
For more information
Hasegawa H, et al. A comprehensive study on spindle cell oncocytoma of the pituitary gland: Series of 6 cases and meta-analysis of 85 cases. World Neurosurgery. In press.