Recurrent Wilms' tumour or retroperitoneal teratoma?

Abstract

The clinical and pathological features of a left renal tumour and a subsequent retroperitoneal tumour in a 2-year-old boy are presented. The nephrectomy specimen showed typical features of a triphasic Wilms' tumour with focal heterologous elements and intralobar nephrogenic rests. The tumour was assessed as clinical stage III and post-operative chemotherapy and radiotherapy were administered. A retroperitoneal mass, detected following completion of postoperative therapy, was mainly made up of skeletal muscle and mature adipose tissue. Nests of epithelium resembling ameloblastic nests and a unique structure reminiscent of a developing tooth were present.

Primary retroperitoneal teratomas: A review of the literature

“…Irregular calcifications do not indicate benign disease, as 12.5% of calcified tumors will be malignant [6]. Toothlike calcifications are helpful in diagnosing teratoma [11]. If calcifications are absent, an opacity or radiolucent mass causing displacement may be observed.…”

“…The presence of neural tissue has been specifically associated with invasion and metastases [10]. The presence of nephroblastomatous tissue may present a diagnostic challenge in children as it may be confused with Wilms tumor [11,12].…”

Retroperitoneal germ cell tumors

“…In our opinion, these 2 examinations are complementary; MRI has the definite advantage of images in the 3 planes, giving surgeons better opportunities to plan their operations and to foresee possible complications. Of course, if in some (very exceptional) cases, even histology is not able to distinguish between, for instance, Wilms' tumor and retroperitoneal teratoma, how would CT or MRI do [16]?…”

Wilms' tumor arising within a mediastinal teratoma

“…Wilms' tumors arising within teratomas are in fact exceedingly rare. To our knowledge, only 6 case reports exist describing Wilms' tumor arising within a teratoma [11,13,15,18,28,29]. Five of these cases were retroperitoneal in location and all occurred in infants or young children [11,15,18,28,29].…”