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

Rare presentation of inflammatory myofibroblastic tumor in the kidney

Inflammatory myofibroblastic tumor (IMT) is a rare pathologic entity that has been mostly described in the lung. It has been reported in nearly every organ, with occurrence in the kidney being extremely rare. IMT has nonspecific clinical and radiological findings and often mimics a malignant process. This is a case discussing the radiologic and pathologic findings of a renal IMT in a 35-year-old female who underwent radical nephrectomy for a right renal pelvis mass that was mistaken for transitional cell carcinoma.

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.

Multiple malignant inflammatory myofibroblastic tumors of the jejunum: A case report and literature review

Inflammatory myofibroblastic tumors (IMTs) are rare neoplastic lesions with a tendency for locally aggressive behavior and recurrence. IMTs most frequently occur in the soft tissues of children and young adults, with the lungs being the most commonly affected site; however, it has been recognized that any anatomical location may be involved. IMT in the jejunum is extremely rare, with only one case previously reported in the literature. The current study describes the case of a 42-year-old woman presenting with intermittent abdominal pain and small bowel intussusception that was identified during a laparotomy. Surgical resection of the jejunum, revealing 3 exophytic tumors, provided specimens for analysis. Following histological examination, a diagnosis of IMT was made. A review of the literature regarding this rare disease is also presented to emphasize the risk of local recurrence and the importance of adequate long-term follow-up.