Inflammatory pseudotumor of the kidney: a case report

A Case of Renal Inflammatory Pseudotumor Leading to Nephrectomy

Inflammatory pseudotumor (IPT) of the kidney is a rare benign disorder with unknown etiology. In IPT patients, some nonspecific symptoms might present, such as fever, hematuria, and back pain. As it can appear on computed tomography and magnetic resonance imaging as a hypovascular mass with surrounding fat stranding, IPT can be misdiagnosed as a primary tumor. Since the clinical symptoms, radiographic features, and preoperative findings can be inconsistent, it is imperative to confirm IPT based on histopathological assessment. In the present study, we describe a case of renal IPT in a 13-year-old girl. The patient was treated with nephrectomy of the right kidney since the preoperative diagnosis was renal carcinoma. Pathological examination revealed an IPT. This article emphasizes the importance of preoperative definitive diagnosis in avoiding unnecessary nephrectomy.

Inflammatory Pseudotumor of the Renal Pelvis

Background: Inflammatory pseudotumor of the kidney is a rare disease of unknown etiology. There are no specific clinical or radiologic findings. The lesion can mimic renal cell carcinoma or transitional cell carcinoma depending on the site of involvement. These tumors, if diagnosed correctly, may respond to medical management. We present a case in which an inflammatory pseudotumor of the renal pelvis was misdiagnosed as a transitional cell carcinoma and unwarranted surgical intervention was performed. Case Presentation: A 39-year-old man presented with left flank pain and gross hematuria. On MRI, there was a hypointense 2.4 × 1.8 cm lesion involving the left renal pelvis. The urine cytology and biopsy of the lesion were inconclusive. On follow-up cans the lesion increased in size and patient had repeated hematuria. The lesion was clinically presumed to be a transitional cell carcinoma of the left renal pelvis. A laparoscopic left side nephroureterectomy along with bladder cuff excision and para-aortic lymphadenectomy was performed. The histology report revealed the lesion to be inflammatory pseudotumor of the renal pelvis. Conclusion: Inflammatory pseudotumor should always be considered in differential diagnosis of pelvic tumors, especially when image findings and biopsies are inconclusive.

A 4-Year-old Boy With Right Renal Space-occupying Lesion Diagnosed With Inflammatory Pseudotumor

OBJECTIVE

To report a rare case of a kidney lesion, finally diagnosed as inflammatory pseudotumor, underwent partial nephrectomy and saved the kidney.

METHODS

Case report and experience sharing.

RESULTS

A 4-year-old boy expressed merely occasionally abdominal pain with space-occupying lesion of the right kidney that was indicative of renal malignant carcinoma. The boy underwent partial nephrectomy and perinephric lymph node dissection, and the mass was histopathologically diagnosed as IPT of renal parenchyma, accompanied with lymph nodes reactive hyperplasia. During the subsequent 20 months' follow-up, the child was all clinically very well, the residual right kidney regrew approximately to the same size as the left one by catch-up growth, remained normal glomerular filtration rate, and did not require additional therapy.

CONCLUSION

Among the affected organs of IPT, kidney is indeed of rare involvement, especially in children. Children has immeasurable potentiality for restoration and regeneration, IPT of the kidney should be given sufficient attention when confronted patients with renal mass lesion in the differential diagnosis, to avoid unnecessary surgical intervention.

Kidney inflammatory myofibroblastic tumor masquerading as metastatic malignancy: A case report and literature review

BACKGROUND

Inflammatory myofibroblastic tumor (IMT) is a rare mesenchymal tumor that is characterized by spindle cells differentiated from muscle fibroblasts and infiltration of various types of inflammatory cells. IMT can occur at any age and at any anatomic site. The most common location of IMT is the bladder in the genitourinary tract. Only scarce cases of kidney IMT have been reported in the literature.

CASE SUMMARY

A 77-year-old woman, with a history of bilateral renal calculus for 15 years, was admitted to the Department of Urology of our hospital complaining of recurrent painless gross hematuria for one month. The treatment with cephalosporin was ineffective. Computed tomography imaging showed a mixed density and slightly heterogeneously enhanced lesion in the middle pole of the left kidney and ipsilateral adrenal enlargement. The patient underwent surgical treatment by retroperitoneoscopic left radical nephrectomy plus adrenalectomy. A large number of typical spindle cells surrounded by plasma cells and lymphocytes were observed microscopically. Immunohistochemical analyses indicated that these spindle cells were positive for vimentin, cytokeratin (CK), Ki-67, CK7, CD34, and CD31 and were focally positive for CD10 and anaplastic lymphoma kinase (ALK-1). Thus, a diagnosis of IMT was made definitively. The patient recovered well after operation, and no recurrence or metastasis was noted during the 22-mo follow-up.

CONCLUSION

Since kidney IMT is very rare and lacks characteristic clinical manifestation, it is easily misdiagnosed as a malignant tumor before operation. Surgery remains the best choice for diagnosis and treatment, and such cases must be followed carefully because of the uncertain biological behavior of this tumor. This report suggests that renal calculus may be one of the causes of IMT, but further investigation is necessary to prove it.

Inflammatory pseudotumor containing necrotizing granulomatous lesions of kidney: a hitherto undescribed entity

Herein reported is a case of inflammatory pseudotumor (IPT) of kidney. It is not described in WHO, AFIP, and other books. A review of the literature revealed about 35 cases. A 76-year-old man underwent nephrectomy under clinical diagnosis of renal pelvic carcinoma. Grossly, a solid tumor was seen in renal parenchyma. Microscopically, it was composed of spindle cell tissue with inflammation and many necrotizing granulomas. Epithelioid histiocytes were abundant but giant cells were few. Lymphocytes and plasma cells were also seen. The features suggested tuberculosis (TB), but Ziehl-Neelsen stains and PCR revealed no TB bacillus. Immunohistochemistry showed that the tumor spindle cells were positive for vimentin, CD68, CD45, and Ki-67 (labeling = 18%), α-smooth muscle antigen, and NSE. Focal staining of KIT (mast cells), S100 protein (Langerhans cells), and CD10 (spindle cells) was present. IgG4 was negative. The tumor spindle cells were negative for other antigens examined.

Inflammatory myofibroblastic tumor of kidney with heterotopic bone formation: An unusual case mimicking a renal malignancy

Inflammatory myofibroblastic tumor (IMFT) or pseudotumor is a rare tumor that can be seen in various organs. It is an enigmatic tumor of unknown etiology and difficult to differentiate from malignancy, clinically as well as radiologically. Histologically, it is composed of variable proportions of proliferating spindle myofibroblasts, fibroblasts, extracellular collagen, lymphocytes and plasma cells. This mainly affects the urinary bladder or prostate. Renal involvement is extremely rare and may pose diagnostic difficulty to the clinician. We describe a renal IMFT, mimicking renal malignancy, having unusual histological features.