Background

Testicular tumors account for 1%–1.5% of male neoplasms and 5% of urological tumors.¹ Most testicular cancers occur in young men aged 18–35 years and the incidence has increased during recent decades, particularly in industrialized countries, with 3 to 10 new cases per 100,000 males per year in Western societies.^2,3 It is the most common solid tumor in males between 15 and 40 years old. At diagnosis, 1%–2% of cases are bilateral, and the predominant histology is germ cell tumor (TGCT, 90%–95% of cases).¹Histologically, TGCTs are divided into seminomas (50%), nonseminomas (40%) and combined tumors (10%).The peak incidence is in the third decade of life for nonseminoma testis and mixed germ cell tumor patients, and in the fourth decade for seminoma testis patients.⁴ More than 50% of germ cell tumors include more than 2 basic germ cell tumor types, except for spermatocytic seminoma.³ In 5% of TGCT patients the primary site is at an extragonadal location. It has a high overall survival with correct treatment and followup, with a low mortality rate in young adults. Nevertheless, it causes approximately 0.1% of cancer-related mortality in men. Testicular tumors are usually diagnosed at ultrasonography and are staged at computerized tomography (CT) or magnetic resonance imaging. Around 20% of cases are metastatic at diagnosis.⁴

A timely diagnosis and intervention are critical to improve survival in these patients.

Stage III TGCTs are treated with radical inguinal orchiectomy, followed by chemotherapy. In some cases where there is a high suspicion that it may be a testicular choriocarcinoma, chemotherapy may be started without histopathology confirmation. In others, radiotherapy is also required to treat the metastasis.^1,4

Growing teratoma syndrome (GTS) is a rare clinical entity that affects patients with nonseminomatous germ cell tumors.^5,6 It is characterized by an enlarging residual mass or recurrent growing masses of the retroperitoneum or other locations that appear during or after chemotherapy, and that are proven to be a mature teratoma in the presence of normal levels of tumor markers. Histological examination is the only way to confirm the diagnosis. GTS typically presents within 2 years of initial treatment after recurrence of mass growth and/or metastasis.^5–8

Case Presentation

We present a 29-year-old male with a mixed nonseminomatous TGCT stage IIIc (American Joint Committee on Cancer-Union for International Cancer Control) who had undergone right orchiectomy and was discovered to have progression of the disease with a large retroperitoneal and mesenteric mass on followup, despite chemotherapy, with negative tumor markers.

Figure 1. Preoperative CT scan of the abdomen showing a large solid cystic mass, measuring 31×20×27 cm, with ascites and possible peritoneal seedings.

He presented to our institution for a second opinion, as he was given no further treatment options and was considered for palliative care after completing extensive chemotherapy (1 cycle of bleomycin, etoposide and cisplatin without response, 3 cycles of etoposide, ifosfamide and cisplatin with partial response, and 4 cycles of paclitaxel, ifosfamide and cisplatin with increase in the abdominal mass). His original biopsy confirmed a mixed TGCT with 50% mature teratoma, 15% immature teratoma, 30% yolk sac tumor, 5% embryonal carcinoma and foci of choriocarcinoma. The mesenteric mass was mixed, solid and cystic, and measured 25×18×8 cm and increased in size during neoadjuvant treatment. A repeat abdominal CT scan showed the same solid cystic mass in his abdomen, measuring 31×20×27 cm, with ascites and possible carcinomatosis (Fig. 1). On physical examination his abdomen was distended with a large and firm palpable mass and a large protruding umbilical hernia (Fig. 2, a). The decision was made to repeat his imaging and to discuss his case at a multidisciplinary team meeting. The abdominal and chest CT confirmed the presence of a large cystic and septated mesenteric mass (24.2×28.4 cm), surrounding various arteries and displacing the bowel, associated to small cystic and solid peritoneal seedings and moderate ascites. Considering these findings and his clinical progress, the possibility was raised of a GTS. Treatment alternatives (cytoreductive surgery, selective embolization) and their risks were discussed with the patient, but acknowledging he had no further chemotherapy options, the decision was made to proceed with surgery mainly to improve his quality of life. He underwent an extensive lumboaortic lymphadenectomy and resection of the retroperitoneal tumor, with repair of the umbilical hernia, through a midline supra- and infraumbilical laparotomy without complications (Fig. 2, b). Abundant ascites and a large solid cystic mass were found. Many of the larger cysts were aspirated to allow for a better view and safer resection, preserving the duodenum, major vessels, the kidneys and the ureters, and complete resection was achieved (Fig. 2, c> and d>). He did not develop any complications and was discharged on postoperative day 6. The histopathology report confirmed the diagnosis of a metastatic mature predominantly cystic teratoma. He underwent a followup CT scan and clinical review 2 and 4 months after the surgery with no evidence of recurrence of the tumor. The CT scan only showed inflammatory changes of the surgical site and a small postoperative residual collection inferior to the right kidney (Fig. 3).

Figure 2. a, preoperative abdominal mass with a large umbilical hernia. b, large abdominal mass completely resected. c, surgical bed with no evidence of residual tumor and preserved surrounding structures. d, appearance of the abdomen after resection of the tumor.

Discussion

Mixed germ cell tumors contain more than 1 germ cell component (in different quantities) and are much more common than any of the pure histological forms, representing 32%–60% of all germ cell tumors. About 90% of the patients with nonseminomatous tumors can achieve complete cure with aggressive chemotherapy. Although prognosis of testicular tumors depends largely on clinical stage, histological type and adherence to the treatment influence the prognosis as well. Metastatic mature teratoma is a common radiological and histopathological finding after chemotherapy for metastatic nonseminomatous germ cell tumors. The leading theory for these residual tumors is the selective chemotherapy resistance of teratomas versus the high chemotherapy sensitivity of the embryonal components.⁵ Metastatic mature teratomas should be resected because of their malignant potential and occasional progression to GTS with the invasion of the surrounding structures.

Figure 3. CT scan of the abdomen 2 months after surgery: inflammatory changes of the surgical site and evidence of a small residual collection inferior to the right kidney, adjacent to the anterior pararenal fascia measuring 52×23 mm, which extends caudally and communicates with another right paracolic collection measuring 65×32 mm, with minimal free fluid in the abdomen.

Conclusions

GTS is an extremely rare condition, with a very poor prognosis without the correct and prompt management. Close followup after treatment for nonseminomatous germ cell tumors is mandatory for early detection of this syndrome, which can occur even many years after tumor onset. Normal blood makers can be misleading, and surgery remains the only curative treatment.