Abdominal Actinomycosis misdiagnosed as liposarcoma
Eunice Vieira E Monteiro1, Joana Gaspar1, Claudia Paiva1
1Centro Hospitalar Universitário do Porto, Serviço de Cirurgia Geral. Porto, Portugal.
Abstract:
Actinomycosis is an uncommon, endogenous, and chronic infection with varied and nonspecific clinical features such as abdominal, pelvic or cervical masses, ulcerative lesions, abscesses, draining fistula, fibrosis, and constitutional symptoms. The disease ensues when the bacteria disrupt the mucosal barrier, invade, and spread throughout interfascial planes. Currently, the diagnosis of actinomycosis is challenging because of its very low frequency and depending on the clinical presentation it may masquerade malignancies. Therapy consists initially in intravenous penicillin, followed by an oral regimen that may be extended until a year of treatment. A timely diagnosis is crucial to avoid extensive therapeutic attempt as surgery. However, a biopsy or drainage of abscesses and fistula's tract may be required not only as a diagnostic procedure as part of the therapy. We report the case of a 72-year-old woman with an abdominal mass initially misdiagnosed as a liposarcoma. A second biopsy of a skin lesion of the abdominal wall made the diagnosis of actinomycosis, avoiding a major surgical procedure. The patient was treated with a long-term course of antibiotics with favorable outcome. Liposarcoma was ruled out after the patient's full recovery with antibiotics and the misdiagnosis was credit to the overconfidence on the immunohistochemical positivity to MDM2.
Insights
Actinomycosis, a rare chronic infection, often mimics cancer, delaying diagnosis. This case highlights how a second biopsy confirmed actinomycosis, avoiding unnecessary surgery and enabling effective antibiotic treatment.
Area of Science:
- Infectious Diseases
- Oncology
- Pathology
Background:
- Actinomycosis is an uncommon, chronic bacterial infection presenting with nonspecific symptoms, often mimicking malignancies like liposarcoma.
- Diagnosis is challenging due to low frequency and varied clinical presentations, including abdominal masses, fistulas, and constitutional symptoms.
- The infection occurs when bacteria breach mucosal barriers and spread through fascial planes.
Observation:
- A 72-year-old woman presented with an abdominal mass initially misdiagnosed as liposarcoma.
- A subsequent biopsy of an abdominal wall skin lesion led to the correct diagnosis of actinomycosis.
- Immunohistochemical positivity for MDM2 contributed to the initial misdiagnosis of liposarcoma.
Findings:
- The patient received a long-term course of antibiotics for actinomycosis.
- The patient experienced a favorable outcome with antibiotic therapy alone.
- Surgical intervention was successfully avoided due to the timely and accurate diagnosis.
Implications:
- Emphasizes the importance of considering actinomycosis in the differential diagnosis of abdominal masses, even when malignancy is suspected.
- Highlights the critical role of biopsy in confirming the diagnosis and guiding appropriate treatment, potentially avoiding extensive surgery.
- Suggests caution regarding overreliance on specific immunohistochemical markers when faced with atypical presentations.
