Actinomycosis - a forgotten chronic infectious disease - case report series.

Actinomycosis is one of the greatest 'chameleons' among infectious diseases. It may imitate inflammation, abscess or a neoplasmatic tumor. Moreover, correct diagnosis is even more challenging due to the fact that the disease takes on various forms like: cervicocephalic, abdominal, or affects the reproductive organs. In order to highlight the diagnostic difficulties of actinomycosis, we have decided to describe six cases of female patients (aged 31-73 years, mean age: 52 years) hospitalized due to actinomycosis in the Department of Infectious Diseases and Hepatology between 2014-2019. Additionally, a case of one patient was described in detail as the course of her disease was exceptionally non-specific. Only in 2 of 6 patients the primary diagnosis was correct. The four other patients were initially suspected with cancer or inflammation. Three of the patients were diagnosed with the abdominal form of actinomycosis, one - neck and head, and one presented both locations. Only histopathological examinations during invasive procedures allowed to state the final diagnosis. An adequate diagnosis was associated with a number of additional tests and delayed appropriate treatment. WBC and CRP were within normal range in all patients. Four patients completed treatment successfully after 60-192 days, one is still on therapy and one is lost to follow-up. In conclusion, common features of actinomycosis presented in this case series include predominance of female gender, abdominal localization and lack of typical symptoms. What is more, therapy with antibiotics, mainly doxycycline and beta-lactams resulted in complete regression of lesions in the majority of cases. Given the examples of our patients we believe that actinomycosis should be considered in the differential diagnosis of all abdominal tumors, especially in women. Abbreviations: WBC - white blood cells, CRP - C-reactive protein, CT - computed tomography, IUD - Intra-Uterine Device, i.v. - intravenous.