Ischial tuberculosis: MRI and mNGS enable early diagnosis in the largest reported case series of twenty two patients

To analyze the clinical features, diagnosis, treatment, and prognosis of ischial tuberculosis (IT), and to evaluate the diagnostic value of MRI and mNGS in the largest reported case series to date.

Data from 22 patients with confirmed IT treated between January 2013 and January 2023 were retrospectively reviewed. Diagnosis was based on histopathology, microbiology, and molecular tests.

The mean age was 31.6 years (11 to 67). Common symptoms included gluteal pain (100.0%), sitting-induced pain (81.8%), and local swelling (59.1%). Computed tomography (CT) revealed lesions in 86.4% of patients, while magnetic resonance imaging (MRI) showed abnormalities in all 18 patients examined. The ischial tuberosity was the most common site of involvement (63.6%). The T-cell spot test for tuberculosis infection (T-SPOT.TB), Xpert Mycobacterium tuberculosis/rifampicin resistance assay (Xpert MTB/RIF), and metagenomic next-generation sequencing (mNGS) showed positivity rates of 83.3%, 83.3%, and 100%, respectively. Histopathological granulomas were observed in 77.3%. Overall, 68.2% underwent surgical debridement. All patients achieved clinical cure with no recurrence at a mean follow-up of 34.7 months.

IT has an insidious onset. MRI (100% sensitivity) is valuable for early diagnosis, and molecular tests, particularly mNGS (100% detection rate), enhance pathogen detection. Surgical debridement combined with standard chemotherapy achieved clinical cure in all patients, but comparative studies are needed to confirm its superiority over conservative treatment.