Late recurrence of Wilms' tumour with exclusive skeletal muscle phenotype 23 years after primary diagnosis

A late recurrence of Wilms' tumour (WT) 23 years after the primary diagnosis is described. The primary tumour occurred in a 10-month-old girl and showed various degrees of differentiation, including skeletal muscle phenotype. A postoperative chemotherapy was performed. Twenty-three years after the surgery, the tumour relapsed: the lesion was exclusively composed of mature skeletal muscle elements (diffuse and intense desmin reactivity) derived from the primary tumour as confirmed by WT1 immunoreactivity. Chemotherapy and radiotherapy have been reported previously to ablate the immature components of WT; especially, chemotherapy can modify the histological type, reducing the immature elements while leaving mature cells unaffected. We can hypothesise that both morphological and molecular features of the tumour as well as the effect of therapy can influence a tumour relapse in WT. The latter results in a high degree of differentiation and a long disease-free interval after the first diagnosis. The association of chemotherapy and radiotherapy to radical nephrectomy has increased the overall survival rate up to 85-90% [3, 6]; however, in spite of these therapeutic improvements, tumour relapses in a subset of patients (15-20%) [12]. Numerous studies have demonstrated that the risk of recurrence can be associated to different features such as histological tumour pattern and loss of heterozygosis (LOH) at 1p and/or 16q, as well as gain of chromosome 1 and other recently described alterations [7, 8, 15, 18]. The recurrence risk is greater within the first 2 years after primary diagnosis (in these patients, the percentage of survival approximately ranges from 24 to 43%), but late relapses have occasionally been reported [ 1, 10]. We in this study report a case of late recurrence of WT 23 years after primary diagnosis.