Renal Pelvic Cholesteatoma: An Uncommon Finding in Children.

Renal cholesteatoma or keratinizing desquamative squamous metaplasia is infrequent in adults and rare in children. We report a case of renal cholesteatoma in a 4-year-old male child who was referred to us as a case of multiple renal calculi with hydronephrosis. We also discuss his management with a review of relevant literature. Copyright:

INTRODUCTION

Cholesteatoma of the upper urinary tract is an uncommon benign condition. Flank pain, the passage of cornified material in the urine, and a filling defect on intravenous pyelography (IVP) constitute the characteristic triad. Earlier, most cases were managed by extensive surgery due to its presumed association with squamous cell carcinoma but now a conservative approach is being followed.. We report a case of renal pelvic cholesteatoma that was referred to us as a case with multiple renal calculi. This is an uncommon condition in children with very few cases reported in literature till date.

CASE REPORT

Our patient, a 4-year-old male, presented with flank pain and pain during passing urine. The patient had these complaints for the past 6 months and was referred to our hospital after an ultrasound report suggested gross right hydronephrosis with multiple calculi in dilated renal pelvis and calyces. There was no history of hematuria. Physical examination was unremarkable. Laboratory data revealed a normal complete blood count, blood urea, creatinine, electrolytes, calcium, and phosphorus. Urine culture revealed no growth and routine urine examination was also insignificant. Intravenous urography showed multiple filling defects in the right renal pelvis [Figure 1]. The left kidney was normal. A Tc 99m DTPA renogram revealed a compromised cortical function of the right kidney with obstruction to outflow at the level of pelviureteric junction (PUJ). The patient was then planned for surgery with a preoperative diagnosis of multiple calculi in the right renal pelvis obstructing at the PUJ. Intraoperatively, a soft growth was encountered at the PUJ and on opening the renal pelvis, soft pultaceous material extruded out [Figure 2]. It was sent for histopathological examination and the surgery was concluded with a right dismembered pyeloplasty over a 3.5 Fr DJ stent. The postoperative course was uneventful. The patient was discharged with advice to return after 6 weeks for DJ stent removal. Histopathological examination showed an inflamed renal pelvis lined by hyperplastic urothelium. The subepithelium showed extensive edema and moderate-to-dense lymphoplasmacytic infiltrate. The cheesy material sent for biopsy showed abundant acellular proteinaceous material along with keratin flakes which were suggestive of cholesteatoma [Figure 3].

Figure 1

Excretory urography showing filling defects in dilated right pelvicalyceal system

Figure 2

Extracted pultaceous material from the renal pelvis and calyces

Figure 3

(a) Photomicrograph showing anucleated squames and keratinous debris (H and E, ×100). (b) Photomicrograph showing keratin debris, fibrin, abundant calcification, minimal inflammation, and focal foreign-body giant cell

DISCUSSION

Cholesteatoma most commonly occurs in the ear. There are few case reports of upper urinary tract cholesteatomas or keratinizing desquamative squamous metaplasia (KDSM) in adults, but we could find only two case reports of renal cholesteatoma in children in English literature.[12]

Histologically, there is “squamous metaplasia of transitional epithelium, keratinization and subsequent desquamation of the keratinized layers. Inflammatory infiltration, parakeratosis, rete-peg formation, and atrophy or dysplasia of the renal parenchyma may also be seen.” The basal layer of the squamous epithelium KDSM is always normal, emphasizing its benign nature.[3] No difference has been found in the histological picture of acquired cholesteatoma in adult and children.[4]

Renal KDSM or cholesteatomatous leukoplakia is usually located in the renal pelvis and calyces. It is more common in adults (97.5% of described cases), with a male-to-female ratio being 3:2.[5] This condition is thought to arise due to chronic urothelial inflammation, though hypotheses of embryological anomaly or even spontaneous transformation of urothelium into squamous epithelium have also been suggested.[36]

Diagnosing this condition is difficult. The clinical and radiological picture can mimic renal stones, renal mass, blood clot, tuberculosis, or papillary necrosis; all of which are more common than KDSM. Elimination of flake-like keratinized material in the urine is considered to be the most characteristic sign.[3] However, this was not present in our case may be due to associated PUJ obstruction. The degree of calcification of the lesion is variable. Cases with minimal calcification may not be detectable on plain X-ray, while those having a significant amount of calcification may appear like calculi. Special studies such as excretory urography and retrograde pyelography, and computed tomography urography can be helpful, but a urothelial tumor must always be included in the differential diagnosis.[3] In our case, the plain X-ray was inconclusive, but excretory urography showed filling defects in the renal pelvicalyceal area and obstruction at the PUJ. DTPA renogram showed decreased cortical function with obstruction at the PUJ. This condition may be associated with renal stones.[78]

In literature, there are reports of nephrectomy being done in cases with renal KDSM due to a mistaken diagnosis of malignancy.[29] Despite some suggestions of its possible progression to squamous carcinoma, there have been no reports of progression to malignancy. Hence, more conservative approaches have been used in recent times. Managing these cases via the percutaneous and transureteroscopic route, or even clinical follow-up, has been described.[1011] Some authors have suggested Vitamin A supplementation as a curative measure in selected cases of auditory cholesteatomas.[12] This may be extrapolated to cases with urinary tract involvement. Removal of cholesteatoma and pyeloplasty was done in our case. The child is doing well at 2-year follow-up without any recurrence.

CONCLUSION

Renal cholesteatoma is an uncommon benign condition. It should be kept in mind when dealing with suspicious renal pelvic masses or when a patient presents with complaints of passing white flakes in the urine. Minimally invasive interventions or clinical follow-up should be advised as per the patient's symptoms after confirmation of diagnosis. Vitamin A supplementation can be tried for treatment and preventing recurrence. Patients should be followed up for possible recurrence and malignancy.

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Conflicts of interest

There are no conflicts of interest.