Primary LAMN-like mucinous neoplasm of the seminal vesicle: a case report and literature review

Background Primary low-grade mucinous neoplasms of the seminal vesicle are extremely rare. Their histopathological features closely resemble those of low-grade appendiceal mucinous neoplasms (LAMN), yet their imaging characteristics have not been systematically reported. Case presentation This article presents a case of a 67-year-old male who had a chief complaint of urinary hesitancy. MRI demonstrated marked enlargement of the right seminal vesicle due to a well-circumscribed cystic mass measuring approximately 9.0 cm in maximal dimension, with irregular wall thickening and mural nodules. In addition, the patient exhibited ipsilateral renal agenesis and testicular atrophy. The patient underwent 3D laparoscopic resection of the right seminal vesicle mass, and histopathological examination confirmed a diagnosis of primary low-grade mucinous neoplasm of the seminal vesicle. Conclusions To our knowledge, this is the first reported case describing the imaging characteristics of a primary low-grade mucinous neoplasm of the seminal vesicle in association with ipsilateral renal agenesis and testicular atrophy. Given the critical role of MRI in preoperative assessment, heightened recognition of this rare tumor is vital to avoid diagnostic pitfalls and facilitate optimal clinical decision-making.