Spontaneous Regression Of Metastatic Clear Cell Renal Cell Carcinoma: A Report Of A Rare Case And A Review Of The Literature
Mullasseril, A., Lam, A. B., Mitta, A., Morton, D., McIntosh, A., Patel, S., Thai, T., Annan, A., & Ayanambakkam, A. (2024). Spontaneous regression of metastatic clear cell renal cell carcinoma: A report of a rare case and a review of the literature. Urology case reports, 57, 102868. https://doi.org/10.1016/j.eucr.2024.102868
View Original Source →Abstract
Renal cell carcinoma (RCC) is the seventh most common cancer in the United States; clear cell RCC (ccRCC) is the most common subtype. We report a case of spontaneous regression of metastatic ccRCC and discuss possible underlying mechanisms informed by a literature review. While regression of metastatic RCC has been described following nephrectomy or treatment of the primary tumor, spontaneous regression is rare. Postulated underlying causes include tumor necrosis and immune-mediated responses. Of 29 identified cases of spontaneous regression, only ours occurred after only a biopsy. Better understanding of the pathophysiology of spontaneous regression in RCC will improve its management.
Case Details
Disease Location
Paraspinal muscles, kidney, lymphnodes.
Personal Characteristics
52-year-old male. History of idiopathic pulmonary fibrosis and type 2 diabetes mellitus, occupational exposure to sand blasting, aluminum, and industrial cleaning products
Clinical Characteristics
Presented with right flank pain, and progressively worsening clinical condition leading to inability to work. CT scan revealed a 12 × 10 cm heterogeneously enhancing left renal mass, along with enlargement of the left renal vein. Additionally, a heterogeneous mass was identified in the right paraspinal muscle, accompanied by prominent retroperitoneal lymphadenopathy and bilateral pulmonary nodules, indicative of metastatic disease. Histopathological examination of the left renal mass via CT-guided core needle biopsy showed sheets of tumor cells with focal clear cell changes. Immunohistochemical stains performed were positive for ca-ix, pax-8, with patchy amacr expression. Consistent with a diagnosis of ccrcc with extensive necrosis. Similarly, biopsy of the paraspinal muscle mass revealed ccrcc with rhabdoid changes. Next-generation sequencing of paraspinal muscle mass tissue identified a von hippel-lindau mutation (exon 2) and polybromo-1 mutation. Before initiating systemic therapy, he was admitted due to severe anemia and chest pain, accompanied by elevated troponin t. CT revealed worsening pulmonary nodules, mediastinal lymphadenopathy, persistence of the left renal mass, new liver lesions, and cardiac lesions. Echocardiogram findings raised concerns about a right ventricular mass suggestive of metastatic disease and intraventricular thrombosis. After receiving packed red blood cells and initiating treatment with apixaban for thrombus management and antibiotics for suspected infection, he was discharged. The patient was subsequently started on nivolumab and ipilimumab one-week post-discharge. However, this regimen was complicated by the development of pneumonitis, necessitating steroid therapy and discontinuation of further ipilimumab.
Remission Characteristics
CT showed a significant decrease in the size of the paraspinal muscle mass. Upon follow-up in the clinic (57 days post-biopsy), he reported significant improvement in flank pain and interim enhancement in performance status, even prior to systemic treatment. Upon repeat CT cap, a complete response was observed in the paraspinal muscle mass, along with im- provements in the renal mass and retroperitoneal lymphadenopathy,
Treatment & Mechanisms
Proposed Remission Mechanisms
An invasive procedure resulting in cellular injury can theoretically lead to exposure of intracellular neoantigens and a positive immune response.
Clinical Treatment
Biopsy, apixaban, antibiotics, steroid therapy