This condition, sometimes called fungal “bezoar”, is classically caused by Candida spp. However, N/A(L): Penicillium, N/A(L):Phycomycetes and N/A(L):Aspergillus have also been reported as the cause of fungus balls.


Fungus balls are commonly associated with the following underlying conditions:

  • Diabetes mellitus
  • Nephrolithiasis
  • Any other cause of urinary obstruction

Clinical Manifestations

Patients with a fungus ball may have almost any presentation. Asymptomatic fungus balls are seen when the obstruction is incomplete. Complete obstruction is often associated with a urosepsis-like picture that includes fever, chills, and flank pain. Some patients will report having spontaneously passed whitish debris (“fungus balls”) in their urine.

Specific Diagnostic Strategies

  1. Laboratory Studies. Common findings among patients with Candida fungus ball include:
    • Marked leukocytosis
    • Pyuria
    • Hematuria
    • Concomitant bacterial urinary tract infection
  1. Imaging Studies. Expected findings for the following studies are [827]:
    • Abdominal ultrasound
      • Dilatation of the collecting system
      • Echogenic, nonshadowing mass in the renal pelvis
    • Intravenous pyelogram
      • Irregular mobile filling defects, sometimes smooth and rounded but occasionally castlike defects within the renal pelvis, ureter and/or bladder. Differential diagnosis for this type of finding includes tumor, calculus, blood clot or papillary necrosis.
      • Poor to simply no visualization of the affected kidney
      • Hydronephrosis
      • Hydroureter


Percutaneous nephrostomy with subsequent irrigation of renal pelvis with amphotericin B has been explored in individual cases with satisfactory results [5, 1696 ].
This strategy has been also used in (A):neonates with positive results [2336, 2473]. However, as most cases in this particular population are related to invasive candidiasis, concomitant systemic administration of antifungal agents is encouraged. The choice of therapy follows the general guidelines for therapy of (A):invasive candidiasis.

Difficult Clinical Situations

Fungus balls in Neonates

Fungus balls are the most frequent manifestation of renal candidiasis in neonates [330, 1787]. Between 35 to 42% of neonates hospitalized in a neonatal ICU who develop candiduria will have renal candidiasis. The majority of these cases include a fungus ball [330, 1787].

Fungus balls in neonates are a frequently related part of the syndrome of neonatal invasive candidiasis. A small proportion of cases are due to urinary tract congenital malformations [154, 197, 644, 1301, 1843, 2463].

Clinical presentations include unilateral or bilateral renal obstruction with or without renal insufficiency [330, 1787, 2336]. Diagnosis is easily established with renal ultrasound [154, 330, 2052, 2463]. Therapeutic interventions include percutaneous nephrostomy, amphotericin B irrigation, and systemic antifungal therapy [154, 197, 644, 1301, 1843]. A surgical intervention may be required if problems maintaining placement of the percutaneous catheters emerge [197]. Noninvasive medical management with amphotericin B, 5-flucytosine, and forced diuresis has been advocated by a few authors [46], but we feel that establishing good drainage is critical.