Synchronous Breast and Kidney Carcinomas Following Treatment for Hodgkin's Lymphoma in Young Adulthood: A Case Report and Literature Review.

Background/Objectives: Multiple primary malignancies (MPMs) are defined as the occurrence of two or more independent primary tumors in the same patient, histologically distinct and not of metastatic origin. Patients treated for Hodgkin's lymphoma (HL) carry an increased risk of developing secondary malignancies, especially after chemotherapy and radiotherapy. The synchronous occurrence of breast and kidney carcinoma in this population is extremely rare. Methods: We present a 41-year-old female patient with a history of HL treated at the age of 23 with ABVD chemotherapy and supradiaphragmatic radiotherapy. Results: During staging for a newly diagnosed breast tumor (ER+/PR+/HER2+, pT1cN0), an incidental renal mass was identified and histologically confirmed as clear cell renal cell carcinoma (pT1aNxMx, G2). A multidisciplinary team performed simultaneous partial breast resection with sentinel lymph node biopsy and nephrectomy. The postoperative course was uneventful, and adjuvant systemic therapy was initiated according to oncological guidelines. Conclusions: Synchronous malignancies in HL survivors pose a clinical challenge, as they must be distinguished from metastatic disease and require coordinated therapeutic planning. Risk factors include prior radiotherapy, chemotherapy, genetic predisposition, and family history. This case highlights the importance of long-term surveillance of HL survivors, particularly young women, due to their elevated risk of secondary malignancies. Synchronous breast and kidney carcinomas after HL therapy are extremely rare and demand an integrated multidisciplinary approach. Early recognition and coordinated therapy are crucial for optimizing outcomes and contributing to a better understanding of the etiology and pathogenesis of multiple primary malignancies.