Analysis of misdiagnosis and 18F-FDG PET/CT findings of lymph node tuberculosis

Abstract

OBJECTIVE: To investigate 18F-FDG PET/CT findings of tuberculous lymphadenitis and analyze the causes of misdiagnosis. METHOD: Between 2013 and 2021, a retrospective review was conducted on 22 patients at Jiangxi Provincial People’s Hospital Affiliated with Nanchang University who had lymph node tuberculosis confirmed by histology or clinical investigation. Subjective judgment and quantitative analysis were adopted. RESULTS: Out of 22 patients, 14 are male and 8 are female. The average age was 55.5 years (55.5±12.4). The most common site of lymph node tuberculosis (LNTB) is the mediastinum (41.5%), followed by the neck (24.4%) and the abdominal cavity (21.9%). Half of the patients have more than one site affected. More than half of LNTB patients (54.5%) are concurrent with other types of TB, especially PTB. Among the 41 biggest affected lymph nodes, the average maximum diameter, minimum diameter, SUVmax and the lesion SUVmax/SUVmean liver ratio are 22.04±8.39, 16.93±6.75, 9.72±5.04 and 6.72±3.60, respectively. There is a poor correlation coefficient of 0.236 between the FDG uptake and the size of the biggest affected lymph node. Patients who are concurrent with no other TB have the significantly higher FDG uptake than patients who are concurrent with other TB (12.42 vs 8.02) (p = 0.005). Among these cases, 6 cases (27.3%) are accurately diagnosed with LNTB, all of which have pulmonary tuberculosis as a complication. However, 16 cases (72.7%) are misdiagnosed as lymphoma (50%), sarcoidosis (13.6%), and lymph node metastasis (9%). CONCLUSIONS: This study demonstrates that 18F-FDG PET/CT is very useful in detecting LNTB because tuberculous granulomas show significant levels of glucose uptake. It proves to be an effective method for revealing lesion extent and discovering additional lesions that morphological imaging is missed. However, 18F-FDG PET/CT is not able to reliably distinguish LNTB from lymphoma, sarcoidosis, and metastatic lymph nodes. Nonetheless, 18F-FDG PET/CT allows for the selection of the most optimal biopsy location, and thus has potential to detect early treatment response and distinguish between active and inactive lesions.

A Comparison Study of Lymph Node Tuberculosis and Sarcoidosis Involvement to Facilitate Differential Diagnosis and to Establish a Predictive Score for Tuberculosis

“…18-FDG-PET/CT at diagnosis is positive in 97.6% of patients with confirmed lymph node TB (it detects more lesions than CT) and discovers unknown lesions in 53.7% of cases [3]. It is also important to assess the activity of the lesions, guide biopsy and determine disease extent [1,3,[20][21][22]. In Sarda-Mantal et al's study, SUV max on 18-FDG-PET was the best criterion to discriminate between healing and residual disease at the end of treatment and was confirmed in Harkirat, Vorster and Ankrah's studies [1,3,18,22].…”

Imaging Features and Recent Advances in Lymph Node Tuberculosis

“…However, it can suggest the site for successful biopsy and differentiate between active and inactive nodes. 4…”

DDX58 and CXCL10 have potential as key biomarkers for lymph node tuberculosis

“…The main clinical manifestations of LNTB are masses in the neck, armpits, groin and other parts. With the disease progresses, the patient's lesions are painful, and severe symptoms such as low fever and night sweats will occur in severe cases (13)(14). However, clinically, LNTB often occurs simultaneously with other types of TB, and its atypical clinical manifestations complicate diagnosis and clinical treatment, ultimately leading to poor clinical outcomes or poor prognosis for patients (4,15).…”