Primary Actinomycosis of the Stomach: A Review of the Literature for A Rare Entity.

Background/Objectives: Primary gastric actinomycosis is extremely rare and only a limited number of cases are published in the literature. Actinomycosis is caused by anaerobic Gram-positive bacteria; these microorganisms are members of the normal human microbiome and occasionally lead to infection, especially in immunocompromised patients or patients subjected to abdominal surgery. Advances in personalized medicine, including tailored antimicrobial therapy based on individual patient profiles, may enhance treatment efficacy and reduce unnecessary interventions. Methods: A review was performed through a literature search of the PubMed/MedLine and Scopus databases. Results: A total of 27 patients were included, 15 males (55.56%) and 12 (44.44%) females, with a mean age of 55.11 ± 17.48 years. Among the included patients, 25.93% had a history of abdominal surgery. Abdominal pain (73.08%), weight loss (40.74%), nausea or vomiting (30.77%) and fever (19.23%) constitute the most commonly reported clinical manifestations. Endoscopy (59.26%), computed tomography (48.15%), ultrasonography (22.22%) and magnetic resonance imaging (11.11%) assisted in indicating the primary lesion. Diagnosis was achieved preoperatively in 66.66% of patients, via endoscopy and biopsy (51.85%) or via cultures (14.81%), while nine cases (33.33%) were diagnosed postoperatively. The therapeutic approaches included antimicrobial administration (32%), surgery (24%) or both (44%). The most widely used antimicrobial was penicillin (77.78%) and the mean duration of antimicrobial treatment was 5.85 months. The protocol for this review was registered in Prospero (ID:CRD42025649532). Conclusions: Due to the divergent clinical presentation of primary gastric actinomycosis, clinicians should be aware of this rare entity in order to establish diagnosis in a timely manner and provide prompt and effective treatment.