罕見腎細胞癌 – 案例報告

潘柏勳¹、張延驊^1,2、黃志賢^1,2

¹台北榮民總醫院 泌尿部；²陽明交通大學醫學院泌尿學科，書田泌尿科學研究中心

Metastatic INI1-deficient and Succinate Dehydrogenase B-deficient Renal Cell Carcinoma Treated with Presurgical Pembolizumab/Axitinib followed by Consolidative Nephrectomy – A Case Report

Po-Hsun Pan¹, Yen-Hwa Chang^1,2,3, William J.S. Huang^1,2,3

¹Department of Urology, Taipei Veterans General Hospital, Taipei, Taiwan

²Department of Urology, College of Medicine and Shu-Tien Urological Research Center, National Yang Ming Chiao Tung University, Taipei, Taiwan

Introduction:

Renal medullary carcinoma is an extremely rare subtype of renal cell carcinoma (RCC). This kind of RCC originated from distal nephron, is usually aggressive, more common in young adults and has association with sickle cell disease. Some of these tumors may lack of expression of INI1/SMARCB1. INI1 expressed in all cell, producing proteins called SWI/SNF complex which affects chromatin remodeling, DNA packaging, repair or replication, and also considered to be tumor suppression gene. Lack of INI1 expression might present in rhabdoid tumor or Schwannomatosis.

Succinate dehydrogenase (SDH) deficient RCC is another rare subtype of RCC (about 0.05 to 0.2 percent of renal carcinomas) which is caused by germline mutation of SDH gene. Mostly, presented as low grade tumor with good prognosis, however some may have high grade features with high metastasis rate. SDH mutation might also be found in paragangliomas and gastrointestinal stromal tumors.

Case Report:

A 53-year-old male patient had no prior medical disease, who suffered from low back pain with weight loss 7 kgs for two months ago with radiation and left leg numbness. Poor appetite and body weight loss were also noted. He did not experience any specific symptoms such as abdominal pain, or hematuria; and physical examination were negative. CT scan disclosed a heterogenous enhancing mass about 13.4x8.2cm at upper pole of left kidney with nodular lesion at left adrenal gland, paraortic lymphadenopathy, multiple osteolytic bone lesion at T8, T12, L3, S1, S2; multiple lung nodules and one small hypoenhance nodule about 0.8cm in size over S5 liver. He received US-guided biopsy of left renal tumor and L3 spine lesion with pathology report of metastatic unclassified renal cell carcinoma. He then completed 12 courses of IO/TKI combination therapy with pembrolizumab 200mg iv q3w and axitinib 5mg bid. Palliative external beam radiation therapy was also performed for spine lesion due to potential spinal cord compression. Following systemic therapy, he underwent consolidative left nephrectomy and adrenalectomy with uneventful recovery. The final pathology was composite INI1-deficient renal cell carcinoma and succinate dehydrogenase B-deficient renal cell carcinoma, pT3a.

Conclusions:

We described a rare case of INI1-deficient and succinate dehydrogenase B-deficient renal cell carcinoma. The patient presented with metastatic disease. Due to the poor prognosis, the condition of our patient progressed in 1 month after surgery and discharged home under critical disease. It needs further surveys or studies for therapeutic strategy in these kind of aggressive RCC.