Published online Dec 26, 2019. doi: 10.12998/wjcc.v7.i24.4366
Peer-review started: August 12, 2019
First decision: October 24, 2019
Revised: November 8, 2019
Accepted: November 15, 2019
Article in press: November 15, 2019
Published online: December 26, 2019
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.
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.
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.
Core tip: Herein, we present an elderly woman with kidney inflammatory myofibroblastic tumor (IMT) characterized by painless gross hematuria and misdiagnosed as a malignant tumor with ipsilateral adrenal metastases. Kidney IMT is a rare tumor entity with unknown etiology, diverse clinical symptoms, and imaging manifestations. Renal calculus was suspected to be one of the causes or drivers of IMT because of the constant destruction of the kidney mucosa. The diagnosis of IMT is considered a great challenge before operation. However, the awareness of its existence and deep understanding of its clinical characteristics are essential to avoid misdiagnosis in the differential diagnosis of a renal mass and to provide better management of such cases. Despite the uncertain biological behavior of this type of tumor, most patients get a favorable prognosis after surgery.