Tuberculous Spondylodiscitis with Psoas Abscess Descending into the Anterior Femoral Compartment Identified Using 2-deoxy-2-[18F]fluoroglucose Positron Emission Tomography Computed Tomography

Abstract

A 24-year-old immunocompetent woman underwent whole-body 18F-FDG PET/CT for the evaluation of MRI-suspicious tuberculous spinal lesions. The PET/CT results showed no pathological uptake in either lung, and there were no pathological changes on CT. There was increased uptake in the right psoas muscle, extending continuously down anterior to the right hip joint, posterior to and around the trochanteric region of the right femur, and into the right thigh, with an SUVmaxbw of 17.0. Subsequently, the patient underwent CT-guided biopsy as per protocol, which revealed drug-sensitive Mycobacterium tuberculosis, and the patient was started on standard tuberculosis treatment for 12 months.

Keywords: PET/CT; Pott’s disease; drug-sensitive; psoas abscess; tuberculous spondylodiscitis.

Figure 1

A 24-year-old immunocompetent woman with a history of four months of lower back pain and magnetic resonance imaging (MRI) features suggestive of tuberculous spondylodiscitis of lumbar vertebra 2 and 3 was recruited to the Spinal TB X cohort at the Groote Schuur Hospital of the University of Cape Town (ClinicalTrials.gov Identifier: NCT05610098). As per study protocol, the patient underwent whole-body 2-deoxy-2-[18F]fluoroglucose (FDG) positron emission tomography (PET) computed tomography (PET/CT). PET/CT showed no pathological uptake in either lun’s and there were no pathological changes on CT (A). There was increased uptake in the right psoas muscle extending down anterior to the right hip joint, posterior to and around the trochanteric region of the right femur and into the right thigh, with an SUVmaxbw of 17.0 ((B,C) white triangles; (D,F,H,J) white arrows). On CT, the psoas muscle had an altered density, which spread caudally all the way into the lateral compartment of the thigh ((E,G,I,K), white arrows). Increased uptake was also seen in the left psoas muscle, with an SUVmaxbw of 8.04. A discrete 80 mm long by 40 mm wide psoas collection is noted on the left on CT ((E), orange arrow). In the L2–4 region, vertebral collapse with 50% destruction of L2 ((L,M), white arrow), significant body destruction of L3 ((L,M), orange arrow), and beginning erosion of the anterior body of L4 ((L,M), blue arrow), with an SUVmaxbw of 13, were noted. Subsequently, the patient underwent CT-guided biopsy as per protocol, which revealed drug-sensitive Mycobacterium tuberculosis, and the patient was started on standard tuberculosis treatment for 12 months.