Clear cell sarcoma; acute renal failure; encephalopathy; Osteolytic metastases/cutaneous metastases; Obstructive uropathy; This literature-non-study case was reported in a literature article and describes the occurrence of CLEAR CELL SARCOMA OF SOFT TISSUE (Clear cell sarcoma), ACUTE KIDNEY INJURY (acute renal failure), ENCEPHALOPATHY (encephalopathy), URINARY TRACT OBSTRUCTION (Obstructive uropathy) and SARCOMA METASTATIC (Osteolytic metastases/cutaneous metastases) in a 26-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) for COVID-19 prophylaxis.     No Medical History information was reported.    In 2021, the patient received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. In 2021, the patient experienced CLEAR CELL SARCOMA OF SOFT TISSUE (Clear cell sarcoma) (seriousness criteria death, hospitalization and medically significant), ACUTE KIDNEY INJURY (acute renal failure) (seriousness criteria hospitalization and medically significant), ENCEPHALOPATHY (encephalopathy) (seriousness criteria hospitalization and medically significant), URINARY TRACT OBSTRUCTION (Obstructive uropathy) (seriousness criteria hospitalization and medically significant) and SARCOMA METASTATIC (Osteolytic metastases/cutaneous metastases) (seriousness criteria hospitalization and medically significant). The patient was treated with PAMIDRONATE DISODIUM ongoing since an unknown date at an unspecified dose and frequency; RASBURICASE ongoing since an unknown date at an unspecified dose and frequency; ALLOPURINOL ongoing since an unknown date at an unspecified dose and frequency; NIVOLUMAB ongoing since an unknown date at an unspecified dose and frequency and IPILIMUMAB ongoing since an unknown date at an unspecified dose and frequency. The patient died in 2021. The reported cause of death was Clear cell sarcoma. It is unknown if an autopsy was performed. At the time of death, ACUTE KIDNEY INJURY (acute renal failure), ENCEPHALOPATHY (encephalopathy), URINARY TRACT OBSTRUCTION (Obstructive uropathy) and SARCOMA METASTATIC (Osteolytic metastases/cutaneous metastases) outcome was unknown.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): In 2021, Aspiration bone marrow: revealed normocellular marrow (70%)   with focal involvement by a nonhematopoietic metastatic tumor (20%).. In 2021, Biopsy: malignant melanoma. In 2021, Biopsy bone: revealed normocellular marrow (70%)   with focal involvement by a nonhematopoietic metastatic tumor (20%).. In 2021, Biopsy lymph gland: revealed normocellular marrow (70%) with focal involvement by a nonhematopoietic metastatic tumor (20%)., A melanoma-specific molecular analysis on the lymph node biopsy sample was negative for variants in BRAF, GNA11, GNAQ, HRAS, KIT, and NRAS. and Negative for variants in BRAF, GNA11, GNAQ,   HRAS, KIT, and NRAS.. In 2021, Biopsy skin: revealed anastomosing cords and fascicles of pleomorphic cells throughout the mid- and deep dermis, diffusely positive for SOX-10 and also consistent with CCS.. In 2021, Blood calcium (8.6-10.4 mg/dl): 1.7 mg/dl. In 2021, Blood creatinine (0.44-1.03 mg/dl): 1.18 mg/dl elevated. In 2021, Blood lactate dehydrogenase (98-192 U/L): 1097 U/L elevated. In 2021, Blood uric acid (3.0-6.8 mg/dl): 9.1 mg/dl. In 2021, Computerised tomogram: with intravenous contrast demonstrated conglomerates of cardiophrenic, retroperitoneal, bilateral iliac chain, and bilateral inguinal lymph nodes, with the largest node being in the left iliac chain and measuring 7.4 cm.. In 2021, Computerised tomogram abdomen: with intravenous contrast demonstrated conglomerates of cardiophrenic, retroperitoneal, bilateral iliac chain, and bilateral inguinal lymph nodes, with the largest node being in the left iliac chain and measuring 7.4 cm.. In 2021, Computerised tomogram head: with contrast revealed no intraparenchymal metastases. In 2021, Cytogenetic analysis: revealed an abnormal karyotype with an EWSR1-ATF1 gene fusion identified by FISH and copy number losses in CDKN2A, CDKN2B, and MTAP.. In 2021, Fluorescent in situ hybridisation: abnormal   karyotype with an EWSR1-ATF1 gene   fusion. Copy number loss in CDKN2A, CDKN2B, and   MTAP. In 2021, Histology: numerous cohesive clusters of large and monotonous tumor cells were noted. Singly scattered tumor cells were also detected. These tumor cells had a high nucleus-to-cytoplasmic ratio, round nuclei with fine chromatin, 1 to 3 nucleoli, and clear to eosinophilic cytoplasm. Ki-67 expression was 40%.. In 2021, Immunology test: tumor cells were positive for HMB- 45, Melan-A, SOX10, and CD99 and negative for S100, AE1/AE3, desmin, SALL4, and Oct3/4. On flow cytometry, a lymphoma cell population was not identified, and both T cells and natural killer cells appeared normal via antigen profiling.. In 2021, Interleukin level (Unknown-= 2 picogram per millilitre): 11.5 picogram per millilitre elevated. In 2021, Laboratory test: demonstrated recurrent hyperuricemia and hypercalcemia with renal impairment, hyponatremia, and lactic acidosis.. In 2021, Magnetic resonance imaging head: revealed a right frontal bone lesion suspicious for metastasis but no intra- parenchymal lesions.. In 2021, Physical examination: hard ecchymosis over the pubis and erythema over the left flank with nontender, firm lymphadenopathy in the left inguinal area. and left inguinal lymphadenopathy without   overlying skin changes.. In 2021, Positron emission tomogram: revealed multifocal FDG-avid lymphadenopathy, lytic osseous lesions, and a left lower quadrant abdominal wall mass; overall radiographic findings were most suspicious for lymphoma (Figure 2). Hydronephrosis and left ovarian enlargement with mild FDG uptake were also noted.. In 2021, Ultrasound scan: demonstrated multiple abnormal inguinal lymph nodes. In 2021, X-ray: showed no acute or healing fracture.     For mRNA-1273 (Moderna COVID-19 Vaccine) (Unknown), the reporter did not provide any causality assessments.  Company comment: This literature non study case concerns a 26-year-old, female patient with no medical history information reported, who experienced the unexpected serious (fatal, hospitalization and medically significant) event of clear cell sarcoma and serious unexpected (hospitalization and medically significant) events of acute kidney injury, obstructive uropathy, sarcoma metastatic and encephalitis. The symptoms started approximately 5 days after the second dose of mRNA-1273. As reported, patient presented with painless lumps in her left groin 5 days after receiving a second monovalent Moderna COVID-19 vaccine. On physical examination, left inguinal lymphadenopathy without overlying skin changes was noted. This was suspected to be reactive adenopathy from her recent immunization. Six weeks later lymphadenopathy, now associated with left lateral hip pain was noted. Ultrasound of the left inguinal region was performed due to persistent lymphadenopathy and it demonstrated multiple abnormal inguinal lymph nodes, suggestive of a malignant process. Patient further developed abdominal pain, persistent left inguinal lymphadenopathy, constipation, nausea and vomiting, fatigue, abdominal skin discoloration, and a 15-lb weight loss. CT showed conglomerates of cardiophrenic, retroperitoneal, bilateral iliac chain, and bilateral inguinal lymph nodes. Additional findings included moderate left hydronephrosis, diffuse lytic osseous lesions, a left adnexal soft tissue lesion suspected to be of ovarian etiology, a large indeterminate lesion measuring in the left flank that infiltrated the abdominal muscles, and external compression of the left iliac veins and patient was subsequently admitted for obstructive uropathy and hematologic consultation due to concerns about a possible lymphoproliferative disorder. Although initially lymphoproliferative malignancy and then malignant melanoma were considered after immuno-cyto-hematological and molecular testing clear cell sarcoma diagnosis was established. Patient developed acute kidney injury likely due to obstructive uropathy, and later developed encephalitis with osteolytic and cutaneous metastases diagnosed. The patient was treated with comfort measures as eventually passed away. Per authors it is unclear how COVID-19 vaccination contributed to this patient's clinical presentation; but consider the possibility of vaccine being a factor in initiation of investigation that led to the delayed diagnosis of cancer. Considering the nature of event and lack of biological plausibility for causality the events are assessed as not related to mRNA-1273. The benefit-risk relationship of mRNA-1273 is not affected by this report.   No concomitant medications were reported.  The symptoms painless lumps in her left groin, fatigue, 15-lb weight loss was subsumed under clear cell sarcoma. The symptom nausea was subsumed under acute renal failure. The symptom altered mental status was subsumed under encephalopathy.  Hypercalcemia was attributed to diffuse osteolytic metastases, and hyperuricemia and acute kidney injury were suspected to be from obstructive uropathy rather than tumor lysis syndrome. The urology team placed a left ureteral stent. She was discharged to outpatient follow-up with a diagnosis of metastatic melanoma.  A percutaneous nephrostomy tube was placed because of the acute kidney injury.  she developed fever and hypotension, requiring transfer to the intensive care unit and, eventually, mechanical ventilation and inotropic support. Broad- spectrum antibiotics were initiated again, and a repeat infectious work-up remained unrevealing. An increased confluence of her abdominal rash was also noted, prompting a biopsy of the skin rash. The possibility of cytokine release syndrome in the setting of dual immunotherapy was considered.  She developed acute renal failure accompanied by worsening encephalopathy. An urgent hemodialysis was recommended. After multidisciplinary family meetings, the patient and her family elected to proceed with comfort measures, and the patient died later the same day.  During clinical investigation patient developed lactic acidosis, hyponatremia, hypocalcemia, hyperuricemia and Somnolence as a symptoms.; Reported Cause(s) of Death: Clear cell sarcoma