A Case of Urethral Carcinoma With Cardiac Metastasis and Pulmonary Tumor Thrombotic Microangiopathy Confirmed by Autopsy.

Cardiac metastasis and pulmonary tumor thrombotic microangiopathy (PTTM) are uncommon, often fatal complications of malignancy, and are rarely reported in urothelial carcinoma. We report an autopsy-confirmed case of a primary urethral carcinoma in a female patient that progressed into both cardiac metastasis and PTTM. A 70-year-old woman complaining of a palpable urethral mass was referred to our urology department during treatment for an infected hip prosthesis. Her history included stage IIIB cervical cancer treated with pelvic radiotherapy, followed by long-term intermittent self-catheterization for neurogenic bladder. Imaging demonstrated a urethral tumor without distant metastases, and initial needle biopsy suggested squamous cell carcinoma. Multimodal therapy was initially considered but limited by infection and renal dysfunction. Local radiotherapy achieved initial tumor reduction, and she subsequently underwent anterior pelvic exenteration with right nephroureterectomy for a severely atrophic right kidney. Pathology revealed invasive urothelial carcinoma with squamous differentiation and positive pelvic lymph nodes. Four months post-surgery, she developed lower limb edema and deep vein thrombosis. Echocardiography revealed a right ventricular mass, initially suspected to be infective vegetation or tumor thrombus. Treatment was limited by bleeding risk, and the cardiac mass progressed, ultimately leading to death. Autopsy disclosed a large tumor nearly filling the right heart chambers, histologically consistent with metastatic urothelial carcinoma. Microscopic examination of the lungs revealed tumor emboli with intimal proliferation and thrombosis consistent with PTTM. We present a rare case of primary urethral carcinoma complicated by both cardiac metastasis and PTTM, confirmed by autopsy. This report highlights aggressive disease behavior, diagnostic challenges, and the importance of considering uncommon metastatic patterns in advanced urothelial malignancies.