Metastatic Clear Cell Renal Cell Carcinoma with an Unknown Primary in a Living Donor Kidney Transplant Recipient (original) (raw)

2018, Clinical case reports and reviews

Background: Renal cell carcinoma (RCC) commonly metastasizes, and unusual sites of spread are characteristic. However, metastatic RCC without an identified primary site is extremely rare, and only a few cases have been documented. We report the first case of clear cell RCC identified in retroperitoneal, supraclavicular, and mediastinal lymph nodes (LN) without a primary site in a kidney transplant patient. Case report: A 68-year-old patient presented with abdominal pain accompanied by weight loss, decreased appetite, and night sweats 6 months post female living donor kidney transplant. A CT scan revealed retroperitoneal, supraclavicular, and mediastinal lymphadenopathy. An excisional supraclavicular LN biopsy stained for markers consistent with RCC (pancytokertain, PAX8, CD10, and vimentin). Subsequent karyotyping revealed a female aneuploid cell line and raised suspicion for a donor derived RCC. A primary site for the RCC could not be identified on imaging of the native and allograft kidneys. The patient expired waiting for the pathology report, and an autopsy was performed to identify the origin of the RCC. Autopsy could not identify a primary site and cytologic studies indicated that the cell line was derived from the patient. Additional chromosomal abnormalities identified in the cytologic studies (loss of VHL, PBRM1, SETD2, BAP1, CDKN2A/B TP53) narrowed the diagnosis to clear cell RCC. Conclusion: Metastatic RCC can present without a primary site. IHC plays a vital role in making the diagnosis and cytologic studies can confirm the diagnosis and exclude the renal allograft as the origin in a kidney transplant patient.