Med Pediatr Oncol 2002;39:143–145 Letter to the Editor: Simultaneous Occurrence of Wilms Tumor and Rhabdomyosarcoma in Two Patients To the Editor: Wilms tumor (WT) and rhabdomyo- sarcoma (RMS) are relatively common pediatric tumors. Although both tumors are associated with the Beckwith- Wiedemann syndrome and specific genetic alterations [12], their simultaneous occurrence in a single patient has been reported only twice [3,4]. We report the diagnosis of concurrent WT and RMS in two patients and discuss the genetic implications of this finding. The first patient, a girl from Lebanon, presented at age 32 months with left parotid swelling, exophthalmos, and partial 6th cranial nerve palsy. Physical examination also detected Kartagener syndrome (dextrocardia with situs inversus and immotile cilia) and four large cafe ´-au-lait spots over the abdomen. Her parents were first cousins. MR imaging showed a 5 Â 5 Â 6-cm tumor that dis- located the left mandible and destroyed the floor of the left anterior cranial fossa. CT imaging of the abdomen revealed a 10 Â 10 Â 10-cm tumor in the upper pole of the left kidney. Both masses were biopsied and histologic and immunohistochemical studies showed the facial tumor to be embryonal RMS and the kidney tumor to be anaplastic WT (Fig. 1). The patient was treated with ifosfamide, vincristine, dactinomycin, carboplatin, epirubicin, and etoposide; both tumors responded well to chemotherapy. A left nephrectomy was performed at week 9 of therapy, and she then received 10.8 Gy radiotherapy to the left flank and 50.4 Gy to the residual inoperable facial tumor. After 25 weeks of chemotherapy, the RMS recurred locally and the patient died from intracranial extension of the tumor. The second patient, a girl from Guatemala, presented at age 30 months with left eye swelling. Family history was unremarkable; there was no parental consanguinity. CT imaging of the head revealed a 3- Â 4-cm mass in the left orbital area. CT imaging of the abdomen revealed bilateral renal masses. Bilateral renal biopsy yielded a diagnosis of anaplastic WT in both kidneys (Fig. 2), and orbital biopsy established a diagnosis of RMS (Fig. 3). She began treatment with vincristine, doxorubicin, cyclo- phosphamide, and etoposide. The renal tumors responded well to chemotherapy but little change was noted in the orbital mass. She is currently undergoing irradiation of the orbital tumor. We found only one previous report of the simultaneous occurrence of WT and RMS and one brief mention of an additional patient [3,4]. There are several reports of renal tumors composed partially or entirely of rhabdomyo- sarcomatous elements. Vawter reported the case of a patient with anaplastic WT with rhabdomyosarcomatous differentiation [5], and there are occasional reports of RMS of the kidney [6–8]. Neither of our patients had such elements in their renal tumors. Genetic findings suggest links between WT and RMS. Both tumors are associated with Beckwith-Wiedemann syndrome (BWS) [1] and show loss of heterozygosity at the BWS locus 11p15.5 [2]. This region is the location of several genes that have been implicated in tumorige- nesis. The IgF2 gene encodes a potent growth factor that contributes to the somatic overgrowth and cancer predisposition of BWS. Increased expression of IgF2 has been described in WT [9,10] and RMS [11]. The H19 gene encodes an untranslated RNA of undefined function that suppresses growth when introduced into cell lines derived from malignant rhabdoid tumor and rhabdomyo- sarcoma [12]. A subset of both WT [13,14] and RMS [15] have absent or decreased expression of H19. The p57 kip2 gene encodes a cyclin-dependent kinase inhibitor whose inactivation has been demonstrated in some individuals with BWS. Decreased or absent expression of p57 kip2 ,a putative tumor suppressor, has been documented in both WT [16–18] and RMS [19]. Neither patient had clinical features suggestive of BWS, suggesting that other genetic alterations contrib- uted to their cancer predisposition. Patient 1 had multiple large cafe ´-au-lait spots, which is suggestive of neuro- fibromatosis type 1 (NF1). Both RMS and WT may occur in NF1, but their frequency is less than that of optic nerve glioma, neurofibroma, neurofibrosarcoma, malig- nant schwannoma, astrocytoma, and pheochromocytoma [20]. Although no palpable neurofibromas were detected, the patient’s young age makes it impossible to completely rule out NF1. It is of interest that both of our patients and the patient reported by Vawter [5] had anaplastic histology WT, which is associated with mutations of the p53 gene [21]. The Li-Fraumeni syndrome (LFS) is a familial cancer —————— Grant sponsor: National Institutes of Health; Grant numbers: RO1- CA600419 and P30-CA21765; Grant sponsor: American Lebanese Syrian Associated Charities. *Correspondence to: Dr. Jeffrey S. Dome, St. Jude Children’s Research Hospital, 332 N. Lauderdale Street, Memphis, TN 38105. E-mail: jeff.dome@stjude.org Received 25 October 2001; Accepted 29 November 2001 ß 2002 Wiley-Liss, Inc. DOI 10.1002/mpo.10077