Late Testicular Yolk Sac Tumor With Cerebellar Metastasis and a Rapid Recurrence After a Gross Total Resection: A Case Report.

Yolk sac tumor (YST) is the most common prepubertal testicular tumor. It is considered a subtype of non-seminoma germ cell tumor (NSGCT) that is presumed to have an aggressive behavior with high malignant potential, thus requiring multimodality treatment with resection and chemotherapy. Treatment is curative for the majority of patients, even the ones with relapse after a few years. Here, we describe for the first time an atypical case of YST recurrence 17 years after primary treatment of YST. This is a case of YST in a 32-year-old man who presented with a large cerebellar mass consistent with YST recurrence after being in remission for 17 years. He underwent suboccipital craniotomy and complete excision of the tumor, as evident on postoperative MRI with a plan for stereotactic radiosurgery with dose and fractionation determined by MRI at four weeks postoperatively. However, the four-week MRI postoperatively revealed a large mass that was engulfing the prior resection cavity, indicative of unusual rapid tumor recurrence despite evidence of complete resection. The highly aggressive nature of this tumor should prompt clinicians to consider chemotherapy and radiation earlier than four weeks postoperatively.