Lowstage pure testicular teratoma

Prepubertal

The reported incidence of testicular tumors in children ranges from 0.5 to 2.0 cases per 100,000 boys [6]. Testicular teratoma is the second most common prepubertal testis tumor following yolk sac tumor and occurs with a relative frequency ranging from 13% to 60% [7-9]. On sonographic evaluation, teratomas may demonstrate the appearance of cystic areas with intervening septa and solid areas. In contrast to the cystic appearance of teratomas, other testis tumors in children are typically solid, with the exception of the rare cystic granulosa cell tumor or simple testicular cysts. The presence of calcifications in the tumor is another helpful sonographic finding associated with teratomas; however, the diagnosis must be verified by pathologic examination.

Serum alpha-fetoprotein (AFP) levels are also useful in differentiating teratomas from yolk sac tumors. Teratomas do not stain positively for AFP by immunohistochemistry, and elevated serum AFP levels are not reported in patients with these tumors. In contrast, greater than 90% of yolk sac tumors stain immunohistochemically for AFP, the majority of which also are associated with elevated serum AFP levels [10,11]. Therefore, serum AFP levels should always be obtained during the initial evaluation of a testicular tumor in the prepubertal child.

The natural history of prepubertal testicular teratomas differs significantly from testis tera-tomas in the adult. Metastasis from testicular teratomas in prepubertal children has not been reported, while similar tumors occurring after puberty are known to metastasize [6,12]. Based on this, the treatment of choice for prepubertal testicular teratomas is orchiectomy; however, recent studies with long-term follow-up have demonstrated the safety and efficacy of testis-sparing surgery [13].

Postpubertal

While teratomatous elements are found in 55% to 80% of primary nonseminomatous germ-cell tumors (NSGCTs) in adults, only 2% to 6% of cases are composed of pure teratoma [14,15]. The ultrasonographic and pathologic appearance of pure teratomas is similar in the prepubertal and postpubertal testis. As previously discussed, serum tumor markers are usually not elevated in patients with a pure testicular teratoma. Although pure testicular teratomas have a benign clinical course in prepubertal children, in adults metastases have been reported in 29% to 76% of cases at initial presentation (Table 1) [12,16,17]. Furthermore, retroperitoneal metastases have been identified in approximately 20% of patients with clinical stage I pure testicular teratoma treated

Table 1

The incidence of metastatic disease at initial presentation in men with pure testicular teratoma

Table 1

The incidence of metastatic disease at initial presentation in men with pure testicular teratoma

Total no. of

patients with

Patients with

Reference

pure teratoma

metastases, n (%)

Rabbani et al [12]

29

22 (76)

Leibovitch et al [16]

41

23 (56)

Simmonds et al [17]

14

4 (29)

with primary retroperitoneal lymph node dissection (RPLND) [16,18].

The standard treatment for all germ-cell testicular tumors in adults is a radical orchiectomy performed through an inguinal approach. However, controversy exists concerning the management of the retroperitoneum in patients with clinical stage I pure teratoma. The treatment options for these patients include primary RPLND or surveillance. The incidence of retro-peritoneal metastases in patients with clinical stage I disease is approximately 30% and increases to 75% for patients with clinical stage IIA disease [12,16,18]. For patients undergoing a primary RPLND for pure testicular teratoma, the histologic finding in the retroperitoneal lymph nodes of teratoma or viable GCT is present in approximately 30% and 20% of patients, respectively [12]. The significance of viable GCT in the retroperitoneum of patients with pure testicular teratoma implies that either a small-volume viable NSGCT was not detected on pathologic analysis of the orchiectomy specimen, or these retroperito-neal metastases occurred before the viable GCT elements in the testis underwent necrosis or regression (''burnt-out lesion''). The survival rate for patients with low-volume disease following primary RPLND approaches 100% [12,16,18].

Studies have demonstrated that even in properly selected patients with pure testicular tera-toma, approximately 20% of patients will relapse during surveillance [17,19]. The retroperitoneum is the most common site of relapse, followed by the lungs or elevated serum tumor marker (STM) alone. Survival rates after therapy for surveillance range from 95% to 100% and are comparable to that of primary RPLND [17,19]. For patients with clinical stage I NSGCT on surveillance, a number of factors predictive of retroperi-toneal or systemic failure have been identified, such as a primary tumor stage of T2 (cIb) or greater, lymphovascular invasion, and/or the his-tologic finding of embryonal cell carcinoma predominance [20,21]. Several of these factors may also be helpful in selecting patients with pure testicular tumors for surveillance protocols. Patient compliance is the most important selection criteria for entry into a surveillance program because strict adherence to frequent follow-up evaluations is critical. Because patients with pure testicular teratoma do not have elevated serum tumor markers at presentation and because of the increased incidence of harboring teratoma in the retroperitoneum and the potential for late relapse, strict vigilance is required for surveillance protocols.

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