Oncogenic osteomalacia in renal cell carcinoma: a case report and literature review / 中华泌尿外科杂志

ABSTRACT

Objective To investigate the clinical manifestations, pathologic features, treatment and prognosis of oncogenic osteomalacia (OO). Methods A 17-year-old male patient was admitted.The patient presented with a 4-year history of progressive lower limb weakness, muscle atrophy and joint pain. Lab tests demonstrated hypophosphatemia. Lumbar and pelvic X-ray showed wedging of the lumbar spine and decreased pelvic bone density. Ultrasonography revealed a low-echo and bloodrich mass measuring 15.1 cm× 14.5 cm× 13.2 cm located at the lower pole of left kidney. Computed tomography showed a voluminous enhanced tumor, supplied by the left renal artery, vice renal artery and a branch of the inferior mesenteric artery. A tortuous vein at the lower part of the tumor drained into the left renal vein. A radioactive octreotide scan was used to study an increased radionuclide-uptake lesion which was initially suspected on the CT scan. The patient was preoperatively diagnosed with left malignant kidney tumor and oncogenic osteomalacia. During a left radical nephrectomy performed through a transperitoneal anterior subcostal incision, a round diameter 15 cm tumor covered by twisted veins was found. The patient recovered well postoperatively. Results The histological diagnosis was renal clear cell carcinoma. Immunohistochemical staining detected Vimentin and RCC were positive and Ki-67antigen index was about 2 %. After lesion removal, the paraneoplastic syndrome resolved. At the 11-month follow-up, no recurrence of the disease was observed. Conclusions Oncogenic osteomalacia is rare and OO with renal cell carcinoma has not been reported so far. OO or rickets should be suspected in those patients who presented with metabolic bone disease associated with hypophosphatemia and inappropriate phosphaturia. If OO syndrome was suspected, in addition to past medical history and imaging, a standard meticulous examination should be initiated promptly. Surgical treatment is still necessary once confirmed. And all of them achieved a good prognosis.