Unusual giant low-grade appendiceal mucinous neoplasm: A case report and literature review.

RATIONALE: Low-grade appendiceal mucinous neoplasm (LAMN) is a rare subtype of appendiceal pathology characterized by epithelial hyperplasia, cellular atypia, and mucinous accumulation within the appendiceal lumen, leading to obstructive expansion of the organ. Representing a mere 0.2% to 0.3% of all appendectomies and approximately 0.5% of gastrointestinal tumors, LAMN poses diagnostic challenges in surgical practice.

PATIENT CONCERNS: We conducted a retrospective analysis of a patient with the appendiceal neoplasm. A 39-year-old female presented to Jiaozhou Hospital, East Hospital Affiliated to Tongji University on July 9, 2022, complaining of a nine-day history of right lower abdominal pain, distension, and nausea. Physical examination revealed a palpable measuring 15 × 6 cm in the right lower quadrant, accompanied by tenderness, rebound tenderness, and muscular guarding.

DIAGNOSES: Histopathological examination confirmed the diagnosis of a LAMN without evidence of lymphovascular invasion, serosal, or mesenteric infiltration.

INTERVENTIONS: After antiinflammatory therapy and comprehensive assessment, the neoplasm was excised through three-dimensional laparoscopic surgery.

OUTCOMES: No recurrence was observed during an 32-month postoperative follow-up period.

LESSONS: Despite its rarity, LAMN warrants clinical attention due to its nonspecific symptoms. Computed tomography scans significantly improve preoperative diagnostic accuracy, with pathological diagnosis serving as the gold standard. Surgical intervention is the preferred treatment option, albeit controversies persist regarding surgical extent and the utilization of preoperative and postoperative chemotherapy.