11-year-old white girl with a history of previous health problems. She was admitted when her parents noticed an increase in abdominal volume for approximately 12 days, accompanied by weight loss and lack of appetite. On physical examination, the mucous membranes are pale, and there is a palpable tumour of 8-10cm in the right abdominal flank, with defined borders, firm and non-painful consistency, which passes the abdominal midline. Routine tests show a haemoglobin of 90mg/lt and an erythrocyte sedimentation rate (ESR) of 130mm/1 hour. Chest X-ray is normal, as is the bone survey, simple abdominal X-ray shows calcifications in the tumour, IVUS shows normal sized kidneys, good bilateral renal elimination, no dilatation of the excretory tract, In the IVUS the kidneys are of normal size, good bilateral renal elimination, no dilatation of the excretory tract, only slight displacement of the right kidney downwards and outwards due to the tumour and in the ultrasound scan a solid, echogenic mass of 11cm in diameter, located in the right abdominal flank above and towards the lower pole of the right kidney, but without infiltrating it, is observed. Surgical treatment was decided with the preoperative diagnosis of Neuroblastoma, after blood replacement by transfusion. During the operation, several tumours were observed in the meso of the transverse colon, the largest measuring 7cm, which were resected and removed in their entirety. Macroscopic examination of the surgical specimen revealed whitish tumours with apparently good delimitation, a firm consistency and a whirling appearance, with focal calcifications. Microscopic study showed that the intestinal tumour was made up of a proliferation of fibroblastic cells, with characteristics in some areas similar to smooth muscle cells, foci of calcification and necrosis, and the histopathological diagnosis was myofibromatosis.