Heart Tumor in a Girl with Nephrotic Syndrome, a Possible Association or a Rare Coincidence?

Case report

Nephrotic syndrome (NS) is the most frequent glomerular disease in children defined as nephrotic-range proteinuria and hypoalbuminemia. The majority of children reach a remission with corticosteroid treatment and 80–90% of them will have at least one relapse (Kidney Disease: Improving Global Outcomes (KDIGO) Glomerular Diseases Work Group. Kidney Int 2021; 100: S1–S276, Noone DG et al., Lancet 2018; 392: 61–74). We report a rare case of a child diagnosed with NS and heart tumor.

A girl aged 2 years and 10 months was admitted to the children’s nephrology department for the new onset of NS. On the day of admission, her physical examination was normal except for swollen eyelids. Laboratory tests showed hypoalbuminemia (24.5 g/l), hypoproteinemia (40 g/l), hypercholesterolemia (10,3 mmol/l) and severe proteinuria (protein/creatinine ratio 1698 mg/mmol); all the other tests were within the normal values. We started a treatment with daily prednisone 40 mg (60 mg/m²) and symptomatic therapy. On the third day of hospitalization, we noticed a systolic murmur over the pulmonic valve of a moderate intensity which was not previously present. The cardiologist performed an electrocardiogram (ECG) which was normal and an echocardiogram (ECHO) which showed a tumor of the interventricular septum which was entering the right ventricle outflow tract without clear obstruction but with mild blood flow acceleration. The 24-hour Holter ECG was performed with normal results. Magnetic resonance (MR) with the intravascular application of gadolinium was performed and showed a tumor of size 33x26x26 mm located in the interventricular septum and protruding to the right ventricle outflow tract. The type of tumor was not clear from the imaging. Due to a highly hyperintense and homogenous signal on early gadolinium (EGE), hemangioma was considered a possible diagnosis. Other tumors such as rhabdomyoma or atypical fibroma seemed to be less likely ([Fig. 1]). After an interdisciplinary meeting (nephrologists, cardiologist and oncologist), propranolol treatment was started as a therapeutic test to determine the possible effect on tumor mass reduction seen in hemangiomas. The propranolol was discontinued after 2 months due to the lack of response. As a next step, the “watch and wait” strategy was chosen because there was neither sign of possible malignancy nor complications. In regular check-ups, the tumor was not causing any problems and was not growing. Blood flow acceleration seen in the first ECHO disappeared. The tumor biopsy was planned in case of tumor growth or any other sign of malignancy or complication caused by the tumor. The course of NS was mild, the patient needed low dose of diuretics for only two days and complete remission was achieved within 7 days. Within 6 months, the patient developed corticodependency and was switched from prednisone to Cyclosporin A on which she remained in remission. During the 2-year follow-up, the tumor remained the same size and caused no complications. The case was concluded to be a rare coincidence as we did not suspect any genetic etiology (remission of NS was reached on prednisone treatment) or secondary NS due to the malignant tumor (no growth of the tumor, MR not suggesting a malignant tumor).

Fig. 1 Steady-state free precession MRI (SSFP) – CINE sequence shows a mass in the basal interventricular septum protruding into (but not obturating) the right ventricular outflow tract (a); T2-weighted imaging shows very high signal intensity, however with many artifacts (b); T1-weighted image with isointense signal of the mass (c); high contrast agent uptake at EGE imaging (d); high contrast agent uptake at LGE imaging (e).

Publication History

Article published online:
16 November 2023