A Renal Inflammatory Myofibroblastic Tumor Similar to Cystic Renal Cell Carcinoma

Abstract

We describe and analyze the clinical course and imaging findings of a case of a renal inflammatory myofibroblastic tumor (IMT) that is similar to cystic renal cell carcinoma.“Solitary cysts” on the left kidney were found during a health examination of a 60-year-old female. The patient also had hypertension. She had undergone surgeries twice for limb trauma fracture and had no definite record of hepatitis. There was no tenderness with percussion of the kidney area or edema in the lower extremity. The renal function results, including serum creatinine, blood urea nitrogen, and blood urea, were within the normal range. No gross hematuria or microscopic hematuria was found. An 8.7 cm × 9.2 cm mixed echogenic mass at the upper pole of the left kidney was observed with ultrasound, the majority of which was an anechoic mass that was slightly protruding from the renal capsule and had well-circumscribed borders. After a bolus injection of an ultrasound contrast agent, the mass had rapid enhancement with fast fading. An approximately 9.4 cm × 10.1 cm round-like cyst lesion at the upper pole of the left kidney was revealed by computed tomography (CT) examination of the abdomen; it had edge finishing with well-circumscribed borders. The upper inner wall of the lesion was thick with crescentic soft tissue. The solid content had gradual enhancement on enhanced CT scans. A kidney tumor was considered based on the CT findings.Based on the preoperative examination, the left renal cystic masses were resected. Intraoperative frozen sections were used to further clarify the nature of the lesion, and no significant malignant cells were observed; therefore, the kidney was not removed. The pathological diagnosis was renal IMT. After surgery, the patient recovered and did not have recurrence or metastasis over the course of long-term follow-up.CT images of our patient with renal cystic disease are categorized as Fuhrman grade IV and typically indicate the presence of malignant lesions. However, gradual enhancement of the solid content in our case is different from typical cystic renal cell carcinoma. The nature of the lesion was further identified using intraoperative frozen sections, which helped avoid unnecessary nephrectomy.

Inflammatory Myofibroblastic Tumor A Rare Case in Kidney

“…4 Although there are no specific clinical symptoms of IMT, patients commonly presented as incidental finding (36%) to pain (38%), microscopic or gross hematuria (28%), and constitutional symptoms (23%). 5,9 It is extremely difficult to exclusion of malignancy preoperatively. Renal cell carcinoma, transitional cell carcinoma, malignant lymphoma, xanthogranulomatous pyelonephritis, angiomyolipoma with minimal fat, rhabdomyosarcoma in adults and Wilm's tumor in children are the differential diagnosis of a renal IMT.…”

“…Renal cell carcinoma, transitional cell carcinoma, malignant lymphoma, xanthogranulomatous pyelonephritis, angiomyolipoma with minimal fat, rhabdomyosarcoma in adults and Wilm's tumor in children are the differential diagnosis of a renal IMT. [3][4][5]8 Most diagnoses have been made at the time of surgical intervention, as because it is difficult to obtain enough tissue by CT-guided fine needle aspiration to make a definitive histopathological diagnosis. 10,11 Histologically, IMT is consisting of proliferation of spindle cells associated with various amounts of lymphocyplasma-cytic infiltrate.…”

“…The preoperative diagnosis of renal IMT remains difficult due to its nonspecific manifestations and the mimicry of malignancy by imaging, such as renal cell carcinoma, which possibly leads to nephrectomy. [3][4][5][6][7] Histologically, there is evidence of marked proliferation of myofibroblasts, fibroblasts, histiocytes, and plasma cells. There were few reports of recurrence of IMT.…”

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

“…It is most important to distinguish renal IMT from RCC and sarcomatoid renal cell carcinoma. Cystic renal IMT should be carefully differentiated from cystic renal cancer[28]. In our case, the lesion was assumed to be a renal malignant tumor that had most likely metastasized to the ipsilateral adrenal gland before surgery.…”

Inflammatory myofibroblastic tumor of kidney together with ipsilateral perinephric and periureteric fibrosis

“…[ 8 ] Because the term “pseudoneoplasm” is nonspecific and with the improved understanding of the pathological and immunohistochemical features, IMT has been more widely accepted as the name for this type of tumor. [ 9 , 10 ] The pathogenesis of IMT remains unclear. It is still controversial whether IMT is a kind of reactive hyperplasia lesion or a tumor disease.…”