Multifocal Peripheral Osteoarticular Tuberculosis: Contribution of TEMP/TDM in the Extension Balance
A. Nouatin *1, E. Kpekpeou 1, I. Malki 1, Z. Boustouti 1, FZ. Errazouki 1, N. Ismaili Alaoui 1
*Correspondence to: A. Nouatin, Nuclear Medicine Service of the CHU HASSAN II of Fez.
Copyright
© 2026 A. Nouatin is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Received: 06 October 2026
Published: 01 November 2026
DOI: https://doi.org/10.5281/zenodo.23908322
Introduction
Tuberculosis (TB) is an infectious disease primarily transmitted from person to person, caused by Mycobacterium tuberculosis, or Koch's bacillus (BK) [1]. It constitutes a major public health problem, particularly in countries with intermediate incidence such as Morocco [2]. The pulmonary form is the most frequent clinical presentation and remains the major source of transmission. After primary infection, the bacillus can disseminate via the bloodstream, more rarely via the lymphatic system, and reach virtually all organs, including bones and joints [3].
Osteoarticular tuberculosis (OAT) encompasses all pathological manifestations secondary to the involvement of the musculoskeletal structures of the musculoskeletal system by Mycobacterium tuberculosis (Koch's bacillus). [4] It represents a relatively rare manifestation of extrapulmonary tuberculosis, accounting for approximately 11 to 15% of cases. [5] Multifocal forms, characterized by the simultaneous involvement of several bone and joint sites, are exceptional, particularly in young, immunocompetent individuals.
In this context, comprehensive assessment of osteoarticular involvement presents a diagnostic challenge, particularly in multifocal forms, where some lesions may be subclinical or underestimated by conventional imaging. Bone scintigraphy (BS) and single-photon emission computed tomography/computed tomography (SPECT/CT) allow for whole-skeletal exploration and improved anatomical characterization of detected lesions, thus optimizing the assessment of the extent of the disease.
We report the case of multifocal peripheral TOA in a young immunocompetent patient to illustrate the value of SPECT/CT in initial global mapping and in clinical reassessment in the face of persistent symptoms bone and joint under treatment antituberculosis drug.
Clinical Observation
This is a 19-year-old female patient with no significant medical history, immunocompetent (negative HIV serology, no known immunosuppressive treatment), and unknown vaccination status, being monitored for disseminated multifocal tuberculosis simultaneously affecting the meninges, lungs, lymph nodes, spleen, and musculoskeletal system. Antituberculosis treatment had been initiated five months prior to the scintigraphy, was well tolerated, but with persistent musculoskeletal manifestations.
The musculoskeletal symptoms had been developing for approximately six months. They included pain and stiffness in the left elbow and knee. The patient also presented with painful swelling of the right hand, consistent with tenosynovitis confirmed by MRI and pathology, which necessitated a synovectomy. In addition, swelling of the left hand, left big toe, and right ankle was noted, related to cold abscesses identified on CT and X-ray, which were surgically drained.
In front of the persistence of physical symptoms despite treatment, and the appearance of new swellings, particularly on the left ring finger, a bone scintigraphy was requested in order to search for subclinical deep bone foci and to better define the extent of the osteoarticular involvement.
Scintigraphic Examination
The patient underwent bone scintigraphy (BS) with 99mTc-MDP (740 MBq), including early and late whole-body acquisitions (10 min and 2 h after injection), supplemented by SPECT/CT centered on the elbows, hands, knees and feet to specify the anatomical location of the bone and periarticular foci.
The examination revealed multiple active foci of increased bone and periarticular uptake, visible at both stages of the scan, predominantly peripheral (hands, elbows, right knee, and feet), without involvement of the axial skeleton. The localization CT scan showed, adjacent to these foci, mixed lesions with periosteal reaction, consistent with active osteomyelitis and osteoarthritis, most often associated with extension to the adjacent soft tissues, in accordance with the patient's clinical presentation.
The ultrasound confirmed the main locations already identified by conventional imaging, while also revealing a greater extent of peripheral osteoarticular involvement. In particular, it highlighted several additional foci affecting the right elbow, right knee, carpal bones bilaterally, the distal radioulnar joint, and the right intercarpal joints, as well as extension to the phalanges of the hands and feet. SPECT/CT further defined the anatomical location and morphological characteristics of these lesions.
Discussion
Osteoarticular tuberculosis (OAT) results from hematogenous dissemination of Mycobacterium tuberculosis from a primary visceral focus, most often pulmonary [6] , after a variable latency period. Multifocal osteoarticular involvement constitutes less than 10% of OAT cases [7] .
Since multiple peripheral forms are even more exceptional, particularly in immunocompetent patients, few studies in the literature have focused on imaging modalities for assessing their extent. A comprehensive evaluation of osteoarticular involvement is a major diagnostic challenge, not only to confirm or rule out its multifocal nature, but also to optimize the therapeutic strategy and ensure appropriate clinical follow-up.
In the early stages, standard radiography has limited sensitivity, as bone abnormalities are only detectable after significant mineral destruction [8]. CT and MRI offer excellent anatomical resolution and allow for better characterization of lesions, but their segmental nature remains a limitation for assessing the extent of multifocal disease.
Conversely, bone scintigraphy (BS) with technetium-99m-labeled bisphosphonates has the advantage of examining the entire skeleton in a single acquisition. Thanks to its high sensitivity to osteoblastic changes induced by inflammatory or infectious processes, it can detect subclinical foci or those not identified by segmental morphological imaging [9] . This high sensitivity makes it a particularly effective examination for investigating multifocal osteoarticular tuberculosis.
Tuberculous osteoarthritis (TOA) can present in various anatomoclinical forms, predominantly involving the spine, tuberculous arthritis or osteoarthritis, osteitis, and, more rarely, soft tissue involvement such as tenosynovitis and bursitis. [1]
BK can reach the joint directly via the synovial membrane, or indirectly via the adjacent bone, which is often the epiphysis in adults and the metaphysis in children [10] . This explains why joint involvement secondary to bone involvement often results in a picture of osteoarthritis [10] .
According to published series, joint tuberculosis is located in the lower limbs in approximately 72% of cases [11]. Tuberculous osteitis, which represents nearly 19% of musculoskeletal locations, can affect all bones, with a predilection for the metaphyses of long bones as well as the bones of the hand and foot [6] . These observations are consistent with the predominant bone involvement in our patient, which preferentially affects the extremities.
Several foci of tuberculous osteoarthritis affected the small bones of the hand and foot, extending to the phalanges. SPECT/CT revealed osteolytic areas associated with focal cortical destruction, sometimes complicated by cold abscesses in the soft tissues, appearing as thin-walled, hypodense collections. Involvement of the joint interfaces of the elbows and right knee was also observed (Table 2).
Spinal involvement is the most frequent manifestation of osteoarthritis of the spine (OA), most often taking the form of multivertebral spondylodiscitis [12]. In the series by C. Ben Taarit and F. Sadouki, it represented 62% and 66% of cases, respectively [13,14]. Conversely, exclusive or predominant bone involvement of the peripheral skeleton remains unusual [8]. The absence of spinal involvement in our patient thus constitutes a unique presentation, highlighting the importance of a systematic examination of the entire skeleton, even in the absence of spinal clinical signs.
However, combining bone scintigraphy with SPECT/CT significantly improves the diagnostic value of the examination [15]. The fusion of functional and morphological data makes it possible to discriminate between bone lesions and purely articular or soft tissue lesions, while also identifying underlying structural abnormalities [16]. This hybrid approach thus increases the specificity of the examination while reducing the number of equivocal abnormalities observed on planar images alone [17].
In the reported case, this complementary approach proved crucial. Beyond confirming previously documented lesions, whole-body scintigraphy enabled a comprehensive mapping of active sites, revealing several previously asymptomatic or unrecognized foci , particularly in the right elbow, right knee (whereas the initial pain was reported on the left) , and intercarpal joints. SPECT/CT acquisition then validated the osteoarticular nature of these uptakes and specified their precise anatomical location. Furthermore, identifying all these sites optimizes the assessment of the true severity of the disease, thus ensuring an objective basis for targeted monitoring of areas at high risk of functional complications.
It is important to emphasize, however, that areas of increased uptake observed on scintigraphy do not necessarily indicate their etiology, and clinical correlation remains essential. In this context, SPECT/CT integration optimizes the morphological characterization of functional foci detected on planar imaging, thereby increasing overall diagnostic specificity.
Conclusion
Multifocal peripheral osteoarticular tuberculosis without spinal involvement is an exceptional clinical presentation that can delay diagnosis. Our work demonstrates that, in the face of persistent symptoms despite treatment, planar bone scintigraphy combined with SPECT/CT remains a valuable tool. By providing comprehensive whole-body mapping and optimal characterization of lesions, it overcomes the limitations of segmental imaging. Its high predictive value in a disseminated context allows for assessment of disease extent and adaptation of the treatment protocol, even in the absence of histological confirmation of the newly described foci
References