| Abstract|| |
Brucellosis remains a major public health problem worldwide. It is commonly found in most developed and developing countries, such as the Mediterranean region, the Middle East, and Latin America. In China, brucellosis is mainly distributed in some of the northern provinces and is relatively rare in Shandong province. Brucellosis has a variety of clinical manifestations, with fever, sweating, fatigue, and migratory joint pain being the most common. Because of the non-specific clinical symptoms, brucellosis is often misdiagnosed as other diseases. Here, we report a rare case of brucellosis of thoracic vertebrae misdiagnosed as thoracic malignant tumor and present a review of related literature.
Keywords: Back pain, brucella, spondylitis
|How to cite this article:|
Fengzhen Y, Lihua J, Jinying W, Maoli Y. A rare case of thoracic brucellosis misdiagnosed as malignant tumor and literature review. Indian J Pathol Microbiol 2021;64:824-6
|How to cite this URL:|
Fengzhen Y, Lihua J, Jinying W, Maoli Y. A rare case of thoracic brucellosis misdiagnosed as malignant tumor and literature review. Indian J Pathol Microbiol [serial online] 2021 [cited 2021 Nov 28];64:824-6. Available from: https://www.ijpmonline.org/text.asp?2021/64/4/824/328565
| Introduction|| |
Brucellosis is the most common zoonotic disease caused by gram-negative coccobacillus of Brucella. Clinical symptoms of brucellosis include undulant fever, sweating, migratory arthralgia, myalgia, and weakness. Due to the variable and non-specific symptoms, brucellosis is easily misdiagnosed as a cold, tuberculosis, and arthritis. However, it is rare for spinal brucellosis to be misdiagnosed as a malignancy. This report presents a rare case of thoracic brucellosis misdiagnosed as a malignant tumor and a review of related literature.
| Case Report|| |
A 57-year-old female patient was admitted to our hospital with a complaint of progressive back pain and low fever over the course of two weeks. She had no other discomfort, no underlying illnesses, no history of long-distance travel and consuming raw meat. Blood examination showed normal white blood cells, erythrocyte sedimentation rate, and procalcitonin, with a slightly higher level of C-reactive protein (5.62 mg/L, where normal: 0.00-5.00 mg/L).
Lumbar magnetic resonance imaging (MRI) demonstrated a decreased signal intensity of the T10-11 vertebrae on T1-weighted images and increased signal intensity on T2-weighted images, which was suspected to be metastatic malignancy [Figure 1]. Positron emission tomography-computed tomography (PET-CT) was then performed [Figure 2]. Lytic bone destruction, thickening diaphragm, and increased FDG (fluorodeoxyglucose) uptake with a maximum SUV (standard uptake value) of 7.0 were present in the left appendage of the T10-11 vertebrae. Slight osteolytic bone destruction with increased FDG metabolism (maximum SUV of 4.4) also appeared in the 11th rib and ischium on the left. In addition, PET-CT revealed local thickening of the left breast with calcification, slightly increased FDG metabolism in the left adrenal gland, left pharyngeal recess, and left cervical lymph nodes. Considering these exceptional results, nasal endoscopy, breast fine-needle aspiration biopsy, craniocerebral and cervical MRI were performed in the following days, but no tumor was found.
|Figure 1: Lumbar spine MRI. (a) T1-weighted sagittal scan showed decreased signal intensity of T10-11 vertebrae. (b) T2-weighted sagittal scan demonstrated increased signal intensity|
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|Figure 2: Total body PET-CT scan. (a) Radionuclide concentration was detected at left appendage of T10 vertebra. (b) Left appendage of T11 vertebra and 11th rib. (c) Ischium on the left and (d) left cervical lymph nodes|
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During hospitalization, the patient developed a fever and blood culture was collected for examination. Three days later, urease positive, gram-negative coccobacilli were found in the blood culture, which were later identified as Brucella Maltese [Figure 3]. A detailed history was obtained once again and revealed that the patient raised sheep at home, which may have been the cause of this disease.
|Figure 3: Culture results. (a) Gram staining of blood culture. Gram-negative coccobacilli were observed (oil lens of OLYMPUS microscope, 1000×). (b) Pinhead colony on blood agar after 48h of incubation. (c) Offwhite, smooth colonies with neat edges on blood agar after 96h of incubation. (d) Urease test in blood culture showed positive|
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Combined with the epidemiological exposure history, clinical manifestations, blood culture, and imaging examination, a diagnosis of Brucella spondylitis was established. After three months of treatment with doxycycline combined with streptomycin and rifampicin, the patient's fever was resolved and her back pain was significantly relieved.
| Discussion|| |
Human brucellosis remains a major public health problem worldwide. About 500,000 cases of brucellosis occur globally each year. In China, brucellosis is mainly distributed in some of the northern provinces, and is relatively rare in Shandong province. The symptoms of brucellosis are generally non-specific, such as fatigue, sweating, joint pain, fever, and gastrointestinal problems. Therefore, clinicians can easily miss this condition or misdiagnose it due to lack of sufficient experience. Brucella species are transmitted by direct or indirect exposure to infected animals or via animal byproducts. In the present case, where the patient had no history of skin trauma or eating raw meat, the most likely transmission of brucellosis was via direct transmission from infected sheep.
After invading the human body, Brucella reach the local lymph nodes and are engulfed by the phagocytes. If the phagocytes fail to kill the bacteria, the bacteria multiplies in the phagocytes, causing them to rupture. A large number of bacteria then enter the lymph and blood circulation and are subsequently seeded throughout the body. A slightly increased FDG metabolism was present in the left cervical lymph nodes in the present case, which may be associated with the Brucella invasion. Brucella is able to survive and replicate within host cells by expressing different virulence factors and using various strategies to avoid the host's immune response.
Blood culture or local culture of Brucella is the gold standard when diagnosing brucellosis. However, the sensitivity is very low, with a positive rate of 50–70% in blood culture. Lambourne JR. suggested that bone marrow culture with a sensitivity of 65–95% should be conducted in patients with suspected brucellosis. In addition, the increased agglutination titer of Brucella also supports brucellosis.
Imaging detection also plays an important role in the diagnosis of brucellosis. Esmaeilnejad-Ganji believe that MRI may be the best way to diagnose and locate the causes of spondylodiscitis, epidural abscess, or compression on the spine associated with brucellosis. Bozgeyik et al. found that the T1-weighted images of brucella spondylitis patients obtained from the MRI examination of the affected vertebral body, endplate, and intervertebral disc showed a low signal, while the T2-weighted images showed a high signal in the acute phase. In the present case, the MRI examination showed low signal on the T1-weighted image and high signal on the T2-weighted image, which was consistent with Bozgeyik's study. Some scholars believe that PET-CT can also help diagnose Brucella and accurately pinpoint lesion locations. It is worth noting that brucella spondylitis should be differentiated from spinal metastatic tumors. Spinal destruction in brucella spondylitis is mostly distributed at the edge of the vertebral body. Hyperplasia of periosteum and spine forms a labial osteophyte with intervertebral disc damage and paraspinal soft tissue swelling that may be accompanied by a localized abscess. While spinal destruction in metastatic tumors is often involved in jumps and posterior vertebral body, the vertebral arch and appendages are more easily involved without including the intervertebral disc. It is not difficult to diagnose spinal metastatic tumors based on age, symptoms, and primary tumor history.
In conclusion, this report described a rare case of thoracic brucellosis misdiagnosed as a malignant tumor in a non-epidemic area, resulting in great mental harm and financial burden to the patient. This suggests that detailed medical history collection is crucial. Patients with a history of exposure to cattle and sheep or eating raw meat or unpasteurized milk should be highly suspected of brucellosis and sent for culture and serological tests repeatedly. In addition, clinicians should improve their understanding of this disease and enhance their ability to differentiate it from other spinal conditions.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
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Conflicts of interest
There are no conflicts of interest.
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Department of Laboratory Medicine, Qingdao University Medical College Affiliated Yantai Yuhuangding Hospital, 20# Yuhuangding East Road, Zhifu District, Yantai - 264000, Shandong Province
Source of Support: None, Conflict of Interest: None
[Figure 1], [Figure 2], [Figure 3]