2 | CASE DESCRIPTION
Our patient is a six-month-old male infant. He was found to exhibit right cryptorchidism after birth, and one month ago his parents took him to see a doctor because of this cryptorchidism. During the doctor’s examination, a mass was discovered in the lower abdomen, and the patient was therefore admitted to the Department of Thoracic and oncological surgery of our hospital for further examination and treatment. However, just after hospitalization, the patient exhibited progressive hepatomegaly, dyspnea, paroxysmal tachycardia, and paroxysmal hypertension, that had not been previously detected. Chest radiography revealed cardiomegaly, and echocardiography revealed cardiomyopathy with an ejection fraction of 34%. The patient was diagnosed with acute heart failure and treated using digoxin, milrinone, furosemide, and spironolactone, which failed to resolve these symptoms. He was therefore transferred to the intensive care unit (ICU) due to acute heart failure, hypertension, and poor left ventricular contractility.
After transferring to the ICU, The patient exhibited a heart rate of 160 beats per minute, a respiratory rate of 55 breaths per minute, 100% blood oxygen saturation, and the blood pressure (BP) was 134/102 mmHg. Cardiac examinations revealed grade II systolic murmur, low heart sound, and a regular rhythm. A hard 5 cm x 5 cm x 4 cm mass was detected within the lower right abdomen upon palpation. The liver was palpated 3 cm below the right costal margin. We performed a series of laboratory tests, and blood chemistry analyses revealed elevated levels of liver enzymes (aspartate aminotransferase 417.2 U/L, normal: 0-40 U/L; alanine aminotransferase 351.5 U/L, normal: 0-40 U/L), elevated troponin T (348.8 ng/L, normal:≤ 14 ng/L), and markedly elevated pro-B-type natriuretic peptide (>35000 pg/mL, normal: < 646 pg/mL). Substantial increases were also detected in plasma renin activity (684.7 µIU/mL, normal: 3.11-41.2 µIU/mL), angiotensin I (18.74 ng/mL/hr, normal 0.15-2.33 ng/mL/hr ), angiotensin II (76.78 ng/mL/hr, normal 25-60 ng/mL/hr ), and plasma aldosterone (2000 pg/mL, normal: 30-160 pg/mL). Plasma metanephrine levels were within the normal range (1615.9 pmol/L, normal: 413.9-4434.2 pmol/L), and low urinary metanephrine levels were detected (3 nmol/d, normal: 68.9-378 µg/d). Cardiomegaly and diffuse pulmonary infiltration were detected through chest radiographic imaging (Fig. 1A), with echocardiography revealing dilated cardiomyopathy with an ejection fraction of 38.4%, a shortening fraction of 18.1%, grade 2 mitral regurgitation, and no evidence of intracardiac thrombus or heart defects (Fig. 1C). Abdominal magnetic resonance imaging (MRI) revealed an inhomogeneous quasi-circular soft tissue mass (48.7 mm × 49.5 mm × 52.8 mm) (Figs. 1E and 1F), ascites, and bilateral pleural effusion.
The patient underwent emergency ICU treatment for CHF, hypertension, and left ventricular dysfunction with oral digoxin, spironolactone and intravenous milrinone and furosemide. However, owing to elevated renin-angiotensin-aldosterone levels, BP control was difficult. When the patient was treated with low-dose captopril (0.3 mg/kg), he developed severe hypotension, with BP dropping from 134/75mmHg to 69/32mmHg within 30 minutes and the drug was immediately discontinued. Antihypertensive drugs were then exchanged for urapidil and then sodium nitroprusside, with BP gradually returning to the normal range. However, there was still an occasional paroxysmal increase in BP. Owing to dyspnea, non-invasive ventilation was required to provide breathing assistance. After all of these treatments, the patient exhibited improved left ventricular ejection fraction (LVEF; from 34% to 58%) and BP (from 158/110mmHg to 117/68mmHg). After hemodynamic stabilization had largely been achieved, the mass was resected through an open surgical procedure on day 22 of hospitalization.
Pathologic examination revealed a well-circumscribed 6.0 cm x 5.0 cm x 5.0 cm mass consistent with ERWT without anaplasia (Fig. 2A). Microscopic analyses revealed triphasic histological findings characteristics of a Wilms tumor, including stromal, epithelial, and renal blastema elements. Testicular tissue was observed covering the tumor surface intraoperatively, but there was no evidence of tumor invasion of the surrounding tissues, including epididymal or testicular tissue. Embryonic renal tissue remnants were observed around the tumor. The tumor exhibited positive immunohistochemical staining for WT-1 (Fig. 2B), EGFR, CK19, AE1/AE3, and CAM5.2.
Postoperatively, the patient’s BP returned to the normal range and antihypertensive drugs were discontinued immediately following surgery, whereupon BP remained stable. Plasma renin activity returned to the normal range within one day postoperatively, and cardiac size and function returned to normal within 24 days after surgery (Fig. 1B and 1D). He is currently undergoing adjuvant chemotherapy treatment (vincristine, doxorubicin, and actinomycin D) as per the recommendations of the International Society of Pediatric Oncology (SIOP)[4] at a local hospital.
A follow-up was conducted in our hospital two months after surgery. Cardiotonic drug use was gradually tapered until being fully discontinued, and the patient’s heart rate, BP, and cardiac function have since remained stable. To date, it has been 4 months since the operation, and a recent telephone follow-up indicated that he has undergone four courses of chemotherapy and remains in stable condition. Additionally, his chest and abdominal computed tomography (CT) scans performed at a local hospital have shown no evidence of recurrence four months after treatment.