Bilateral renal leiomyoma with 5 year follow-up: Case report

Abstract

Renal leiomyomas are exceptionally rare benign tumours of the kidney. Although the renal leiomyomas usually do not metastasize, the differential diagnosis between renal leiomyomas and malign lesions (leiomyosarcoma or renal cell carcinoma) cannot be done by radiological examinations, but is possible by histological examination. Surgery is the preferred treatment. After surgery, the prognosis is excellent without recurrence. Although uterine leiomyomas can be multicentric, renal leiomyomas have been single lesions. We report an incidentally detected case of bilateral renal leiomyoma in a 50-year-old woman with a 5-year follow-up. We also review the literature and discuss clinical, radiological and histological features of renal leiomyomas. IntroductionLeiomyomas are benign neoplasms of the smooth muscles, usually occurring in the uterus.1 Renal leiomyomas are exceptionally rare neoplasms that occur at a much lower frequency (0.001%) and show a marked female predominance.1 They rarely present with flank pain and hematuria. 2Renal leiomyomas are usually detected as single-kidneymasses. 3 There are no reports in literature regarding longterm survival or subsequent recurrence with sarcomatous differantiation.We present a 5-year case of bilateral renal leiomyoma detected via contrast-enhanced computed tomography (CECT), magnetic-resonance-imaging (MRI), and histopathologic images. Case reportA 50-year-old female, with migraine, presented with a nonspecific complaint of left flank pain. The hematological, biochemical parameters, and urine analyses were within normal limits. Ultrasonography revealed hypoechoic 30 × 25-mm left mid-pole and 11 × 10-mm right lower-pole renal-masses. CECT of the abdomen revealed a 30 × 35-mm well-circumscribed mid-polar exophytic left renal-mass enhancing less than renal parenchyma on corticomedullary phase with a suspicious renal pelvis invasion and a 10 × 10-mm right lower pole exophytic mass showing a similar enhancing pattern (Fig. 1).Gadolinium-enhanced MRI revealed a 30 × 35-mm well-circumscribed mild exophytic mid-pole renal-mass with renal pelvis invasion; no pathological lymph nodes were detected. On T1-weighted images, both lesions were isointense to muscle tissue and hypointense to renal parenchyma. Enhanced T1-weighted images revealed a peripheral and centrally reticular enhanced left renal mass. Both lesions had no intracellular fat on inphase/outphase images. Malignancy was suggestive due to intense diffusion restriction on diffusion-weighted images (Fig. 1).The left renal mass had renal pelvis invasion on MRI; therefore left radical nephrectomy was performed. Active surveillance was planned for the right renal-mass.A microscopic examination of the left renal mass revealed a leiomyoma. Necrosis, nuclear pleomorphism, and mitotic activity were not detected. Immunohistochemically, the tumour stained strongly with smooth-muscle-actin (SMA) (Fig. 2). HMB45, S100 and desmin were negatively stained.MRI and CECT findings were re-evaluated according to the histopathological fi...