Small Desmoplastic Round Cell Tumor of the Kidney following Hodgkin Lymphoma: Case Report and Literature Review.

Introduction: Desmoplastic small round cell tumor (DSRCT) is a rare and aggressive sarcoma that is most commonly present in males with abdominal and peritoneal invasion. There are potential curative therapeutic options, but survival remains poor. To this day, there have only been 22 reported cases of primary renal DSRCT in the literature and thoracic DSRCT has been rarely reported with very little known about effective therapy. This is the first reported case of renal DSRCT following a primary malignancy, and it is further distinguished by the application of whole-genome sequencing and targeted biological therapy. Case Presentation: The literature on renal DSRCT was reviewed, and we describe a patient with thoracic relapse of DSRCT following a primary renal lesion, initially treated with radical nephrectomy and 14 cycles of chemotherapy (doxorubicin 225 mg/m2, cyclophosphamide 11.4 g/m2, ifosfamide 63 g/m2, etoposide 3.5 g/m2, and vincristine 12 mg/m2). The patient also had a distant history of nodular lymphocyte predominant Hodgkin lymphoma, in remission for 5 years following three cycles of doxorubicin 150 mg/m2, vincristine 8.4 mg/m2, prednisone 840 mg/m2, and cyclophosphamide 2.4 g/m2. Treatment with pazopanib for DSRCT was attempted but discontinued due to significant toxicity. Conclusion: DSRCT remains a highly aggressive malignancy with limited treatment options and poor prognosis. Our case highlights the rarity of primary renal DSRCT and its potential for thoracic relapse, further emphasizing the challenges in disease management.