INTRODUCTION: We report an interesting presentation of renal leiomyosarcoma, a rare renal tumor.
CASE PRESENTATION: A 64 year-old woman presented with cough and dyspnea for 6 months. The patient donated her kidney to her daughter 10 years back, who had end-stage renal disease due to systemic lupus erythematosus. Chest radiograph of the patient was normal before donating kidney. Two years after the renal transplant, patient's daughter was found to have a lesion in the transplanted kidney during workup for proteinuria. Biopsy of the lesion showed leiomyosarcoma, which was surgically resected. Two months later, patient's daughter had recurrence of leiomyosarcoma, which responded to further surgical resection and chemotherapy. The patient denied smoking and alcohol abuse. Physical examination was normal. Routine blood tests were normal. Chest radiograph showed a right upper lobe lung mass. Computed tomography of the chest showed 3.6 × 2.5 cm mass in right upper lobe with spiculated borders. Positron emission tomography of the chest showed increased uptake in the right upper lobe lung mass. The patient underwent wedge resection of the lung mass with mediastinal lymph node dissection. Histopathology of right lung mass showed low-grade leiomyosarcoma without mediastinal lymph node involvement. A final diagnosis of primary leiomyosarcoma of the kidney with solitary lung metastasis was made.
DISCUSSIONS: Leiomyosarcoma is a rare renal tumor. Renal leiomyosarcoma, like other types of sarcomas, tend to displace rather than invade the parenchyma, and it is characterized by rapid growth rate, frequent metastasis, and high local and systemic recurrence rates. High-grade sarcomas often metastasize, the lungs being the primary site of spread, and prognosis is poor. The majority of the patients die due to the progression of the disease within a matter of months. Low-grade sarcomas tend to pursue a more indolent course, although local recurrences are common. For the renal sarcomas, the best treatment modality is radical nephrectomy. Leiomyosarcomas, even when confined to the kidney, have a poor prognosis in general with 5-year survival rates of 29–36% (1). In a case series on genitourinary leiomyosarcomas, the primary tumor site in 131 patients was the bladder in 20, the kidney in 26, paratesticular in 57, the prostate in 21 and other in 7. The most common histological subtypes were leiomyosarcoma in 29% of cases and liposarcoma in 26%. 78% of lesions were high grade (2). Sarcomas in solid organ transplant patients appear to have aggressive features with 62% being high grade and 40% metastatic at the time of primary diagnosis with a recurrence rate of 30%. The development of the leiomyosarcoma was more aggressive in the patient's daughter most likely due to her immunosuppressive therapy.
CONCLUSION: The clinical presentation of renal leiomyosarcoma in our case is interesting. It is possible that our patient had primary leiomyosarcoma of the donated kidney with micrometastases to lung 10 years back, which developed into a lesion in the donated kidney in her daughter. Slow growing low-grade leiomyosarcoma developed into a metastatic solitary lung mass 10 years later in the patient. The patient's daughter had more aggressive manifestation of leiomyosarcoma in the transplanted kidney due to immunosuppressive therapy. We are not aware of similar presentation of renal leiomyosarcoma in the medical literature.
DISCLOSURE: Bhavneesh Sharma, No Financial Disclosure Information; No Product/Research Disclosure Information