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Updated: May 1, 2026

Targeted and Selective Treatment of Pluripotent Stem Cell-derived Teratomas Using External Beam Radiation in a Small-animal Model
Published on: February 17, 2019
Growing teratoma syndrome: clinical and radiographic characteristics
Dennis J Lee1, Hooman Djaladat, Nicholas N Tadros
1USC Institute of Urology, Keck Medical Center of USC, Los Angeles, California, USA.
Objectives:
To present an overview of our surgical experience in the management of growing teratoma syndrome.
Methods:
A retrospective analysis of all patients undergoing post-chemotherapy retroperitoneal lymphadenectomy between November 2005 and February 2012 revealed 15 patients who met the criteria for growing teratoma syndrome. Their clinical data, imaging characteristics, and surgical and oncological outcomes were reviewed.
Results:
The median age at diagnosis was 23 years. Primary testis tumors included non-seminomatous germ cell tumor in 12 of 15 patients, seminoma in two of 15 patients and hemorrhagic mass in one patient. Mature teratoma was present in just six (40%) of the orchiectomy specimens. All patients received preoperative chemotherapy. On imaging, the median size of the largest retroperitoneal mass was 7 cm (range 3.9-24.5 cm). The median rate of linear growth was 0.5 cm/month (range 0.03-2.9), and the increase in volume was 9.2 cm(3) /month. All tumors were found to have cystic and necrotic components. Median operative time was 6.2 h (range 4.2-15.2 h). Estimated blood loss was 600 mL (range 100-7000 mL), and median length of stay was 5 days (range 3-19 days). Four patients required resection of non-retroperitoneal growing teratoma masses after post-chemotherapy retroperitoneal lymphadenectomy to achieve tumor-free status. There were two minor (Clavien I-II) and two major postoperative complications (Clavien ≥III). All patients are alive and disease free with a median duration of follow-up of 8 months (range 1-64 months).
Conclusions:
Growing teratoma syndrome tumors vary in their growth rate, but they all appear to have cystic features with necrosis elements on radiographic evaluation. Aggressive surgical excision is associated with excellent outcomes.
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