International Journal of Infectious Diseases 53 (2016) 12–14
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Case Report
A case of Finegoldia magna (formerly Peptostreptococcus magnus) infection mimicking disseminated malignancy Pallavi Basu *, Anwen Williams, Matthew T. O’Brien, Mattheus Brouns, Paul Edwards Nevill Hall Hospital, Brecon Road, Abergavenny, NP7 7EG, UK
A R T I C L E I N F O
Article history: Received 6 February 2016 Received in revised form 7 October 2016 Accepted 11 October 2016 Corresponding Editor: Eskild Petersen, Aarhus, Denmark Keywords: Finegoldia magna Peptostreptococcus magnus Gram-positive anaerobic cocci Intra-abdominal infection Cutaneous infection Disseminated malignancy
S U M M A R Y
A 44-year-old alcoholic (and therefore immunocompromised) hospital cleaner presented with general malaise, weight loss, and erythematous skin nodules. Computed tomography scanning revealed a neck mass invading the thyroid gland, pulmonary infiltrates, liver lesions, and deposits on the anterior abdominal wall, consistent with disseminated malignancy. However, tissue diagnosis showed a necroinflammatory process with no evidence of malignancy. Microscopy and culture of samples failed to detect any infectious pathogen, but after an extended incubation period, Finegoldia magna was isolated. This case study illustrates the importance of tissue diagnosis in suspected disseminated malignancy and raises the risk of acquiring the rarer bacteria amongst hospital staff. ß 2016 Published by Elsevier Ltd on behalf of International Society for Infectious Diseases. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
1. Introduction Finegoldia magna (formerly Peptostreptococcus magnus) is a Gram-positive anaerobic coccus (GPAC) and commensal bacterium of the skin and mucous membranes of the mouth, upper respiratory, gastrointestinal, and genitourinary tracts.1 Although it is a commensal organism, it is potentially a virulent pathogen that may cause life-threatening infections.2 Many different presentations of F. magna have been reported. A unique case of F. magna infection causing a systemic inflammatory response and multiple cutaneous and visceral inflammatory lesions mimicking disseminated malignancy is described herein. 2. Case report A 44-year-old male hospital cleaner presented with symptoms of fatigue, malaise, reduced appetite, significant weight loss, and ‘boils’ on his feet and upper thigh, all of which had appeared in the 3 weeks preceding presentation. He denied gastrointestinal, genitourinary, musculoskeletal, ear, nose, and throat symptoms. He was a smoker and consumed in the region of 100 units of
* Corresponding author. E-mail address:
[email protected] (P. Basu).
alcohol per week. There was no history of foreign travel, exposure to animals, or contagious diseases. Clinically a well-demarcated, abscess-like lesion had developed on his left thigh and another on his right shin, and lesions were visible on both feet. Hepatomegaly and a left-sided abdominal mass were detected. There was no palpable lymphadenopathy. Cardiovascular, respiratory, and oral examinations were unremarkable. Haematological investigations revealed a normocytic anaemia (haemoglobin 10.4 g/dl, mean corpuscular volume 80.9 fl), hypoalbuminaemia (20 g/dl), hyponatraemia (123 mmol/l), and elevated alkaline phosphatase (150 IU/l) and Creactive protein (176 mg/dl). A computed tomography (CT) scan of the thorax, abdomen, and pelvis with contrast was requested for a high suspicion of malignancy (Figure 1). This demonstrated a mass at the root of the neck on the left side, partially destroying the left lobe of the thyroid gland. Multiple small nodules and a patchy ground glass appearance were present bilaterally in the lungs and there was consolidation in the right middle lobe. Additionally a 4-cm lesion was seen in the right lobe of the liver and cystic deposits were apparent in the anterior abdominal wall, with the largest on the left side. Images were consistent with metastatic thyroid malignancy. However, in view of the hyponatraemia, a lung primary with paraneoplastic syndrome was considered a more likely diagnosis.
http://dx.doi.org/10.1016/j.ijid.2016.10.006 1201-9712/ß 2016 Published by Elsevier Ltd on behalf of International Society for Infectious Diseases. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/).
P. Basu et al. / International Journal of Infectious Diseases 53 (2016) 12–14
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following extended incubation, F. magna was isolated from both samples. The organism was sensitive to amoxicillin, and following an extended course of 3 months, the patient’s symptoms resolved completely. The leg lesions were noted to have healed and three follow-up CT scans were performed showing complete resolution of all lesions at 15 months.
3. Discussion
Figure 1. Coronal computed tomography scan (with contrast) showing a liver lesion and cystic lesion on the left side of the anterior abdominal wall (white arrows).
Biopsy of the neck mass revealed cores of skeletal muscles showing extensive necrosis, fibrosis, and inflammation of unknown cause. No thyroid or lymph tissue was detected. Subsequently a liver biopsy showed a necro-inflammatory process with extensive destruction of normal liver tissue. No malignant cells were noted. Gram-staining showed the possible presence of bacteria within cells; stains for fungi and mycobacteria were negative. The suspicion of a systemic infection likely secondary to immunodeficiency was raised; however the possibility of a systemic vasculitis or necrotic neoplasm could not be excluded. Biopsies of the abdominal wall mass exhibited fibrosis, inflammation, and microabscesses, with no evidence of tumour. Additionally, large numbers of macrophages were detected, which raised the possibility of tuberculosis or an atypical infection, but special stains for microorganisms were non-diagnostic. Biopsies from the skin lesion on his right leg showed a reparative response from previous inflammation, with no evidence of malignancy or vasculitis. Serology for hepatitis B and C viruses and HIV were negative; likewise, immunoglobulin and complement assays were normal. Skin swabs were non-diagnostic and the four biopsy samples from the neck, liver, abdominal wall, and skin lesions failed to grow any specific microorganisms indicative of a diagnosis. Repeated blood tests showed an ongoing inflammatory response and anaemia. Negative blood cultures and a normal trans-oesophageal echocardiogram excluded the possibility of bacterial emboli caused by endocarditis. A subsequent fine-needle aspiration (FNA) of both the masses in the neck and abdomen was performed, and
This case study illustrates a unique presentation of F. magna mimicking disseminated malignancy. It is a commensal organism that can become a virulent pathogen causing severe chronic infection in the host.2 This anaerobe is one of the three most frequent species of GPAC isolated from clinical specimens.3 It has been isolated from patients with pulmonary, intra-abdominal, and genital tract infections.2 However, it commonly presents as the agent of bone and joint infections, predominantly in patients with prostheses within 4 months of surgery,4 as well as other soft tissue infections, including diabetic foot infections.2 F. magna more unusually has been isolated in breast abscesses, infective endocarditis, necrotizing fasciitis, meningitis,2 and infections of the neck and submaxillary gland.5 Several cases have been reported of intra-abdominal infections secondary to F. magna,6 and it is the most common GPAC within splenic and liver abscesses.7 This case was unusual as it mimicked disseminated malignancy. Other conditions have been reported that mimic disseminated malignancy, including peritoneal tuberculosis,8 amoebic abscesses,9 and inflammatory myofibroblastic pseudotumours of the liver,10 highlighting the need for tissue diagnosis and prolonged culture. In addition to prolonged culture, the diagnosis of F. magna can require repeated cultures, as a high percentage are negative.1 In the present case, Gram-staining and culture of several biopsy samples were non-diagnostic. However, findings of possible bacteria within cells and the presence of numerous macrophages in biopsy samples raised the suspicion of an atypical systemic infection, thus leading to extended incubation of further samples. 16S ribosomal RNA (rRNA) gene polymerase chain reaction (PCR) is a technique that is used to diagnose bacterial infections particularly when bacterial cultures are negative.11 Thus, it would have likely been a useful test in the diagnosis of F. magna in this case. However, in order to investigate a possible diagnosis of systemic vasculitis or necrotic malignancy in this patient, several biopsy samples were taken from different sites, eventually growing F. magna from the FNA samples, and thus it was not necessary to perform 16S rRNA gene PCR. Once the diagnosis has been made, several antibiotics can be used, including penicillin, amoxicillin/clavulanic acid, piperacillin/ tazobactam, imipenem, metronidazole, cefoxitin, and chloramphenicol.12 This case was shown to be sensitive to amoxicillin and the patient responded steadily over 15 months. Immunosuppression and malnutrition are recognized reasons why commensal organisms may become virulent.13 The present patient was a chronic alcoholic, which may well have been a contributing factor, as alcoholism is associated with both immunosuppression and malnutrition.14 This is the first reported case of F. magna presenting with both intra-abdominal and cutaneous manifestations mimicking malignancy. It is crucial that in such patients a tissue diagnosis is obtained to prevent labelling the patient as incurable. It is important to send samples for microbiology, liaising with the laboratory to ensure that prolonged cultures are performed in order to establish the diagnosis.
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Acknowledgements We are grateful for the CT image courtesy of Dr Mark Robinson, Nevill Hall Hospital, Abergavenny. Conflict of interest: There is no conflict of interest. No competing interest declared. References 1. Finegold SM. Anaerobic infections in humans: an overview. Anaerobe 1995;1:3–9. 2. Murdoch DA. Gram-positive anaerobic cocci. Clin Microbiol Rev 1998;11: 81–120. 3. Song Y, Finegold SM. Peptostreptococcus, Finegoldia, Anaerococcus, Peptoniphilus, Veillonella, and other anaerobic cocci. In: Murray PR, Baron EJ, Jorgensen JH, Landry ML, Pfaller MA, editors. Manual of clinical microbiology. 9th ed., Washington, DC: ASM Press; 2007. p. 862–71. 4. Levy PY, Fenollar F, Stein A, Borrioe F, Raoult D. Finegoldia magna: a forgotten pathogen in prosthetic joint infection rediscovered by molecular biology. Clin Infect Dis 2009;49:1244–7. 5. Bourgault AM, Rosenblatt JE, Fitzgerald RH. Peptococcus magnus: a significant human pathogen. Ann Intern Med 1980;93:244–8.
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