Nephroblastoma is a neoplasm derived from nephrogenic blastemal cells. It is usually seen in the kidneys of children. This disease is rare in adults, and adult extrarenal nephroblastoma is rarer still. When seen, it is usually after chemotherapy in patients with metastatic testicular germ cell tumors.
1,3,7,8 Multiple cases
2,7,9-12 have reported nephroblastomas occurring with teratomas, which are germ cell tumors made up of several types of tissue from different germ layers. They can be well or poorly differentiated and contain tissue quite different from the surrounding tissue. However, because of the rarity of teratoma with a nephroblastoma component, there is little data for its categorization and management. Currently, data exist on approximately 200 patients with teratoma and malignant transformation, but most of these data are in case reports and nearly all have occurred in metastatic cases.
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To our knowledge, only 3 adult case reports have described a testicular teratoma with a nephroblastoma component arising in a nonatrophic testis (
Table). The first case was reported by Emerson et al
2 and described a testicular tumor composed of nephroblastoma, teratoma, and rhabdomyosarcoma in a nonatrophic testis of a 22-year-old man. After chemotherapy, supraclavicular and retroperitoneal lymphadenopathy with metastatic teratoma developed. In this case, the authors were able to use tissue microdissection and loss of heterozygosity analysis to demonstrate a common clonal origin for the nephroblastoma and the components of its metastases.
The second case was reported by Keskin et al
5 and described a testicular teratoma with a nephroblastoma component in a 19-year-old man. In this case, postorchiectomy serum human chorionic gonadotropin and AFP levels were both elevated at 939 mIU/mL and 2904 ng/mL, respectively, and a CT image of the thorax and abdomen showed multiple lymphadenopathies ranging in size from 3 to 7 cm. The patient received chemotherapy with bleomycin, etoposide, and cisplatin, which were later switched to paclitaxel, ifosfamide, and cisplatin. However, the patient had a poor response to chemotherapy and died in the 18th month after diagnosis.
The third case was reported by Alatassi et al
6 and described a case of a mixed germ cell testicular tumor composed of yolk sac tumor, embryonal carcinoma, and mature and immature teratoma with a significant portion of nephroblastoma in a 19-year-old man. The patient had a large retroperitoneal mass, as well as liver and lung metastases. The patient received chemotherapy, and no recurrence was noted at 6-month follow-up. However, imaging after chemotherapy revealed partial response of the hepatic and pulmonary metastases and persistent retroperitoneal mass.
We report a fourth case of a testicular teratoma with a nephroblastoma component arising in a nonatrophic testis, but this time in a 50-year-old man. Pathologically, this tumor appeared similar to the cases described by Keskin et al
5 and Alatassi et al,
6 but imaging suggested either a less aggressive disease or earlier disease process at the time of orchiectomy. Additionally, this tumor exhibited mature characteristics such as squamous epithelium, adipose tissue, and cartilage, which may have affected the disease course compared with a more immature tumor. The CT results that showed a stable aortic node were not concerning, as that node had been correlated to previous CT scans for Crohn disease and had been attributed to inflammation from that disease process. For this reason, retroperitoneal lymph node dissection was not performed. The pulmonary nodules seen on CT images are unlikely to represent metastatic disease given their stable appearance and lack of enhancement on positron emission tomography, but at this time, their malignant potential cannot be completely excluded. Despite the aggressive nature of the disease and treatment with chemotherapy as described in the 3 previous cases, there is evidence in the literature that nephroblastoma in germ cell metastases can be treated with surgical excision alone. A case series and 2 case reports describe nephroblastoma in the metastases of germ cell tumors.
12-14 These metastases were often effectively treated by surgical excision alone and did not exhibit the more aggressive behavior typically associated with secondary components, such as primitive neuroectodermal tumor and rhabdomyosarcoma. Therefore, in this stable patient, the decision to forgo further surgery or medical treatment seems reasonable, though this conclusion should be interpreted with caution given limited long-term follow-up.