Quadruple Primary Malignancies: A Rare Case of Breast, Bladder, Lung, and Laryngeal Cancer.

Background: Multiple primary cancer (MPC) is defined as two or more primary malignant tumours in the same or a different organ that are simultaneous or metachronous. The reported incidence of MPC varies between 2 to 17%. The vast majority are patients with two primary neoplasms, while quadruple cancers are extremely rare. We present the first documented case of quadruple primary malignant neoplasms, comprising breast ductal carcinoma, papillary urothelial carcinoma, laryngeal fibrosarcoma, and lung squamous cell carcinoma. Case presentation: A 55-year-old female first presented in 2006 with a palpable lump in the right breast and was first diagnosed with breast cancer. In 2010, following haematuria, urothelial carcinoma in the bladder was identified, with more than 15 recurrences in a 13-year period. In 2014 urothelial carcinoma of the renal pelvis and proximal ureter was detected. She developed hoarseness and in 2019 a laryngeal fibrosarcoma was found. During follow-up in 2022, she was diagnosed with lung cancer. The patient received multiple rounds of chemotherapy, radiotherapy and surgical interventions. In June 2023 the patient died due to chemotherapy-related complications. Conclusions: This case highlights the importance of adapting treatment to the individual patient, long-term monitoring and the necessity. LEARNING POINTS: Long-term multidisciplinary follow-up is essential for patients with multiple primary malignancies, as timely surveillance can enable early detection and management of new cancers.Individualized treatment decisions are crucial when standard surgical or chemoradiation options are limited by treatment intolerance or patient refusal.Delayed initiation of appropriate sepsis management can critically impact patient outcomes; despite optimal subsequent treatment, disease progression may become irreversible.