A Case Report of an Invasive Scalp Actinomycosis

Background: Actinomycosis is a bacterial infection characterized by a chronic, suppurative and granulomatous process. The causative organism was identified in 1891 as Actinomycosis israelii. The disease is usually caused by the introduction of the bacteria through minor wound. Actinomycosis was classified by Cope into 3 different forms: cervicofacial (50%), pulmonothoracic (30%) and abdominopelvic (20%). Actinomycosis is an insidious disease but occasionally the clinical course can be more aggressive, involving underline tissue and organs. Involvement of scalp by actinomycosis is rare causing diagnostic dilemma and could be mistaken for different pathologies, such as tuberculosis or carcinoma. The most common clinical findings are local tumefaction with abscesses and sinuses draining pus that contains the granule of the causative organism. CT scan and MRI are aspecific for diagnosis, but they can help in defining the localization and the extension of the lesion. The certain diagnostic is based on cytology and/or biopsy. Case: A 24 year-old-man was admitted to our neurosurgical department with a 16-month history of multiple scalp ulcerated lesions and swelling of the head. He was complaining of headache. Physical examination revealed multiple scalp subcutaneous nodules and ulcerated lesions with swelling of the head. Our examination of the oral cavity revealed a poor oral hygiene condition with multiple caries. The CT scan revealed multiple scalp subcutaneous masses with chronic inflammatory changes of the skull. Routine laboratory test was normal. Surgical biopsy was performed and the histological result was compatible with actinomycosis. After histological confirmation, parenteral Penicillin 20 million units daily were given for 4 weeks. Clinical improvement was observed after completing a 4-week regimen of intravenous antibiotics. Conclusion: Involvement of scalp by actinomycosis could be mistaken for different pathologies, such as tuberculosis or carcinoma. This emphasizes the importance of biopsy for histological confirmation of the disease.