Mesoblastic nephroma—A report from the Gesellschaft fur Pädiatrische Onkologie und Hämatologie (GPOH)

Abstract

BACKGROUNDSurgery alone is the appropriate first‐line treatment for patients with mesoblastic nephroma (MN). Nevertheless, there are reports of local recurrences and metastasis, especially in the cellular subtype. The authors evaluated the outcome of patients with MN who were enrolled in either the International Society of Pediatric Oncology (SIOP) 93‐01/GPOH or the SIOP 2001/GPOH Nephroblastoma Study and Trial.METHODSIn total, 50 patients with MN were analyzed. Eleven patients were suspected antenatally of having a renal tumor. The median age at diagnosis was 18.5 days. Central pathologic review was performed for all specimens. The median observation time was 4.2 years.RESULTSForty‐five patients underwent initial surgery. Five patients older than 6 months received preoperative chemotherapy. Twenty‐nine tumors were classic MN, and 21 tumors were cellular MN. Nine patients had a Stage III MN, 5 of those patients had tumor ruptures, and 8 had positive surgical margins. After they underwent nephrectomy, 40 patients received no further treatment. For the entire group, event‐free survival (EFS) (94%) and overall survival (OS) (95%) were excellent. Patients with a cellular MN, patients with age 3 months or older, and patients with Stage III MN had lower EFS. Three patients developed recurrent disease, and 2 of those patients died. Metastases to the brain, lung, and liver were observed in 1 patient.CONCLUSIONSRadical nephrectomy with accurate surgical‐pathologic staging is the standard of care for children with MN. Nonetheless, a subgroup of patients with MN (Stage III cellular MN in patients age 3 months or older) tends to develop recurrences more often. Further prospective studies will be needed to verify this finding and should help determine whether these patients may benefit from adjuvant therapy. Cancer 2006. © 2006 American Cancer Society.

Nefroma mesoblástico congênito subtipo celular: relato de caso

“…5 The classic variant is similar to the leiomyoma, 1,5,6 described predominantly as solid, firm, of yellowish color, without capsule, with poorly defined margins, 5 fusiform spindle cells and rare mitoses. 6 Cystic areas and necrosis can eventually occur. In contrast, the cellular variant is recognized as a distinct subtype, although both can coexist (mixed subtype).…”

“…There have been varied findings in mixed subtypes. 5,6 Identical translocation has also been reported in infantile fibrosarcoma (IFS), suggesting that the cellular subtype CMN would represent an intrarenal IFS 3 and that it would not be related to WT or renal clear cell carcinoma (RCC), as initially associated. 8 However, when fusiform cells predominate in a child's kidney, the differential diagnosis must include WT, clear-cell type RCC (fusiform cell pattern) and CMN, in addition to other entities that are less common in children.…”

“…9 Metastatic disease, mainly into the lungs, liver, brain and heart and an extensive area of local recurrence are rare events. 6,7,9 Risk factors for recurrence are positive surgical margins, tumor rupture during resection, 1 cellular subtype and patient's age. 6 Patients older than 3 months presenting the cellular variant, with positive surgical margins, tumor rupture during resection or patients with vascular microinvasions are candidates to adjuvant chemotherapy.…”

“…6,7,9 Risk factors for recurrence are positive surgical margins, tumor rupture during resection, 1 cellular subtype and patient's age. 6 Patients older than 3 months presenting the cellular variant, with positive surgical margins, tumor rupture during resection or patients with vascular microinvasions are candidates to adjuvant chemotherapy. 9 The chemotherapy can also be carried out in cases of local recurrence, metastatic disease or patients with inoperable tumors, as some cases of CMN are chemosensitive.…”

“…4 The CMN represents, approximately, 3-10% of all pediatric renal neoplasms and has two histological subtypes: classic and cellular. The cellular subtype accounts for 42-63% of all cases, 5 has larger tumor volumes, occurs significantly more often in older patients, 6 in addition to being more aggressive when compared to the classic subtype. 7 Its diagnosis remains a challenge for pathologists, due to its similarities with other more common pediatric renal neoplasms.…”