Unusual presentations of actinomycosis: a case series and literature review

Introduction: To review unusual actinomycosis cases that appeared as a diagnostic and therapeutic challenge at our institution and to present a literature review on the usual clinical presentations. Methodology: This retrospective review included all patients hospitalized for actinomycosis in a 10-year period at the University Hospital for Infectious Diseases "Dr. Fran Mihaljevic", Zagreb, Croatia. Results: A total of 15 patients were hospitalized during the observed period, 9 (60%) females and 6 (40%) males. The localizations of actinomycosis were: pelvis (5), lungs (3), blood stream (2), colon (1), penis (1), stomach (1), skin (1), cervicofacial region (1). We present four unusual cases: subcutaneous actinomycotic abscess, actinomycosis of the stomach with underlying non-Hodgkin lymphoma, sepsis due to Actinomyces neslundii originated from chronic asymptomatic periapical tooth abscesses and actinomycosis of the distal part of the penile shaft. Conclusions: Actinomycosis was a very rare clinical problem in our clinical practice (0.032% of all hospitalizations and 0.0034% of all outpatients) but among those cases classical clinical presentations were also very rare.