Isolated Renal Mucormycosis in Children

Abstract

Mucormycosis (invasive zygomycosis) usually affects patients with debilitating conditions such as cancer and diabetes mellitus. While renal involvement is not uncommon in disseminated mucormycosis, isolated renal mucormycosis is extremely rare, especially that which does not exhibit any predisposing factors, and few cases have been reported in the literature. We report on 3 children with isolated renal mucormycosis. CASE REPORTS Case 1. A 3-month-old preterm (36 weeks) female presented with a right lumbar mass 2 months in duration without fever or hematuria. The mother appeared healthy, and AIDS and fungal evaluations were negative during gestation. On physical examination a well demarcated hard mass about 6 cm in diameter was palpated in the right lumbar region, which was shown on B-ultrasound (B-US) to be a solid mass of the upper kidney. Right nephroblastoma was diagnosed preoperatively. During exploratory surgery a 6.0 6.0 5.0 cm mass was located in the upper part of the right kidney. The upper part of the mass adhered closely to the hepatic flexure of the colon. Many swollen lymph nodes were found in the mesentery of the ascending colon. Complete resection was difficult, so the majority of the mass was excised and swollen lymph nodes in the mesentery were biopsied. Case 2. A 12-year-old otherwise healthy student presented with a 1-month history of fever followed by 1 week of severe right lumbar pain and hematuria. No history of diabetes mellitus or AIDS was noted. Initial treatment with cephalosporin was ineffective and B-US detected a renal abscess. On admission to the hospital the patient had a body temperature of 40C, and there was marked tenderness and percussion pain in the right lumbar region and slight tenderness in the bladder region. Abdominal computerized tomography showed diffuse enlargement and multiple low density areas of the right kidney with several small perirenal abscesses. Renal perfusion scans demonstrated a nonfunctioning right kidney. Renal abscess was diagnosed and surgically managed. During surgery the right kidney became markedly swollen and soft, and many foci could be seen. There was about 100 ml yellow-white pus in the abscess, which was aspirated for fungal culture, and renal parenchyma was biopsied. Case 3. A 14-year-old boy was hospitalized with fever, hematuria and flank pain 1 month in duration, deteriorating with dysuria, polyuria and pyuria for 2 weeks. No predisposing diseases or recent drug abuse could be elicited. Gross hematuria was observed, routine urinalysis revealed numerous hyphae of Mucor corymbifer and red blood cells were (4). Body temperature was 39.5C. Marked tenderness and percussion pain were noted in the right lumbar region and bladder region. B-US detected a low echo right kidney. Excretory urography and renal perfusion showed a nonfunctioning right kidney. Therefore, renal mucormycosis with infarction was diagnosed. The patient was administered systemic amphotericin B and subsequently underwent right nephrectomy. Pathological results. Frozen sections in cases 1 and 2 demonstrated the mass was mainly inflammatory and necrotic tissue, and many fungi were scattered in the tissue. Hematoxylin and eosin sections confirmed the diagnosis of mucormycosis in all 3 cases, although fungal cultures were negative in case 2. The diagnostic criteria were established only when frozen and hematoxylin and eosin sections were consistent with acute purulent inflammation, and the broad nonseptate fungal hyphae with right angled branches, typical of M. corymbifer, were detected in the tissue (fig. 1). The hyphae were readily observed by silver staining and periodic acidSchiff reaction (fig. 2). The swollen lymph nodes in case 1 were confirmed to be reactive proliferation of inflammation without M. corymbifer. Antifungal treatment (intravenous amphotericin B lipid complex at a daily dose of 2 mg/kg and a total dosage of 300 to 2,160 mg during 3 to 4 weeks, followed by 30 to 50 mg/kg 5-fluorocytocine orally per day for 3 months) followed or was continued after nephrectomy. The 3 children recovered uneventfully, and hepatic and renal function remained normal during followup. DISCUSSION Mucormycosis occurs predominantly in immunocompromised patients, in whom it carries a serious prognosis. Mucormycosis can usually be divided into 5 different subtypes— cerebral, pulmonary, gastrointestinal, cutaneous and systemic, none of which is uncommon. Renal involvement is