Controlateral and mesenteric metastasis of kidney leiomyosarcoma sixteen years after the surgery: A case report

Abstract

Introduction: Primary renal leiomyosarcoma is an extremely rare malignant tumour. It is more common in females than in males and in the right kidney. The diagnosis is difficult. The prognosis is poor because of frequent metastasis and recurrence. Case Report: A 41-year-old woman who had undergone left radical nephrectomy for a kidney tumour 16 years previously presented to our institution with right flank pain. On examination, the left sided mass was a 20 cm encapsulated firm tumor with necrotic and hemorrhagic foci compressing the residual kidney. Histological examination showed a high cellular proliferation of large spindle cells mixed with necrosis and calcification. Nuclei were irregular, hyperchromatic, 4 mitoses/10hpf were counted. Renal capsule and renal vein were tumor free. Tumors cells were positive for smooth muscle actin (AML), neuron specific enolase (NSE), with negative expression for, anti S100, cytokeratin, Epithelial membrane Antigen (EMA), HMB45 and CD34. Histopathological examination concluded to a low grade leiomyosarcoma without capsular effraction neither lymph node invasion measuring 20x13x10 cm. No postoperative treatment was indicated and the patient was lost to follow up for 16 years. Imaging finding (MRI) revealed a solid heterogenic mass at the lower pole of the right kidney. Besides, three mesenteric masses were noticed. A controlateral and mesenteric metastasis of the left kidney leiomyosarcoma was suspected. In order to confirm the diagnosis, an ultrasound guided biopsy of the right kidney lesion was performed. Histopathological findings concluded to a low grade leiomyosarcoma. The patient did not undergo surgery and was referred to a medical oncology center and chemotherapy is in progress. Conclusion: Leiomyosarcoma of the kidney is a rare aggressive tumour. Only few cases are reported in literature. Clinical features are non-specific making generally a delayed diagnosis. The treatment is based on surgery. The prognosis is still poor.