Tenosynovial giant cell tumor, or TGCT, is a neoplasm arising from the synovial lining of joints, bursae, or tendon sheaths. Under the 2020 World Health Organization Classification of Soft Tissue and Bone Tumours, the disease is divided by growth pattern into localized and diffuse types. The diffuse variant, historically known as pigmented villonodular synovitis, is a locally aggressive lesion marked by extensive synovial proliferation, nodular growth, and a strong tendency to recur. It most often strikes the knee, but also appears in the finger, ankle, and shoulder. Hip involvement is uncommon, and that rarity is precisely what makes it so dangerous diagnostically: when a deep, inaccessible joint begins to erode bone, the list of possible culprits is long and includes some far more alarming possibilities.

The patient’s story began one week before admission, when he experienced acute chills and high fever and received three days of empirical intravenous cefuroxime at a local hospital, with partial improvement. Then came the hip pain — acute, severe, worst at night, disturbing his sleep, and worsened by movement. Rest and repositioning did not help. On examination he was afebrile at 36.4°C, with marked tenderness over the right hip, pain provoked by internal rotation, adduction, and flexion, and mildly restricted range of motion. There was no redness, warmth, or swelling, no trauma, no weight loss, and no evening fevers. The distal neurovascular examination was unremarkable. In short, nothing about the physical presentation clearly separated infection from tumor.

Imaging told a more revealing story, though not a definitive one. Magnetic resonance imaging of both hips demonstrated abnormal intra-articular synovial tissue in the right hip, with mild bilateral joint effusion that was more pronounced on the right. The lesion, measuring approximately 27 by 35 by 25 millimeters, showed heterogeneous low-to-intermediate signal intensity on T1-weighted images, heterogeneous signal on T2-weighted images, and heterogeneous enhancement after contrast administration — a signal profile characteristic of TGCT, reflecting variable proportions of fibrous tissue, lipid-laden macrophages, fluid, and hemosiderin deposition. The adjacent anterior acetabular column appeared thinned, and mild swelling of the right obturator externus muscle was noted. Computed tomography then showed joint effusion, cystic low-density intra-articular lesions, and clear thinning and erosion of the anterior and inferomedial acetabular wall. Notably, the plain radiograph showed no definite abnormality, underscoring why advanced imaging is essential when plain films fail.

Laboratory testing deepened the ambiguity rather than resolving it. The white blood cell count was 6.46 × 10⁹/L with 68.4% neutrophils, C-reactive protein was elevated at 34.20 mg/L, the erythrocyte sedimentation rate was 25 mm/h, and procalcitonin measured 0.268 ng/mL — a pattern suggestive of low-grade inflammation but far from conclusive. Serum alkaline phosphatase and tumor markers were normal. Whole-body bone scintigraphy showed increased tracer uptake in both hips, sacroiliac joints, and shoulders, which clinicians judged most consistent with degenerative change. With a recent febrile illness, equivocal inflammatory markers, and a destructive-appearing acetabular lesion, the preoperative differential diagnosis spanned infectious or inflammatory synovitis, synovial chondromatosis, and other aggressive synovial or osseous lesions. Because neither imaging nor laboratory work could deliver a verdict, the team proceeded to surgical exploration after multidisciplinary discussion.

What surgeons found inside the joint settled the immediate uncertainty about the lesion’s nature while illustrating why preoperative diagnosis is so difficult. Intraoperative inspection revealed abundant yellowish joint fluid and diffuse proliferation of synovium-like tissue throughout the right hip, with irregular nodular lesions along the anteromedial and inferomedial acetabular wall. The team performed complete excision of the identified intra-articular lesions and involved synovial tissue, curetted the eroded inferomedial acetabular wall, treated it with alcohol ablation, and reconstructed the localized bone defect with an autologous iliac bone graft. Estimated blood loss was approximately 150 milliliters. Although the lesion contained nodular components measuring up to roughly 1.5 by 3.0 centimeters, it was classified as diffuse-type TGCT because of the widespread intra-articular synovial involvement, the acetabular erosion, and the absence of a solitary encapsulated mass.

Histopathologic examination provided the gold-standard confirmation. Microscopy showed proliferative synovium-like tissue with focal cyst wall-like structures lined by flattened to cuboidal cells, a stroma containing proliferative fibrous tissue, histiocytes, prominent congested vessels, diffuse chronic inflammatory cells, scattered neutrophils, and focal coagulative necrosis. Scattered and clustered foamy histiocytes and variable numbers of osteoclast-like multinucleated giant cells were present, along with hemosiderin granules within the cytoplasm of mononuclear cells and histiocytes — the pigment that gave the old disease its name. Immunohistochemistry showed strong CD68 positivity in the multinucleated giant cells and a subset of mononuclear cells, focal S-100 expression, and a Ki-67 labeling index of approximately 5% to 10%, compatible with low proliferative activity. Focal coagulative necrosis was interpreted as a secondary degenerative or ischemic change, and no cytologic atypia, atypical mitotic activity, or sarcomatous overgrowth was identified. Joint-fluid cultures were negative for bacterial and fungal growth, though the authors caution that prior cefuroxime exposure may have reduced culture sensitivity, so infection could never be excluded on microbiologic grounds alone.

The molecular backdrop of this tumor is one of the more fascinating chapters in modern soft-tissue oncology. TGCT is associated with overexpression of colony-stimulating factor 1, or CSF1, which recruits macrophages to the lesion through what researchers call the landscape effect — a minority population of neoplastic cells orchestrating a massive influx of reactive, non-neoplastic immune cells that constitute most of the tumor’s bulk. This mechanism also underpins CSF1/CSF1R-targeted therapies, which are reserved for selected patients with residual, recurrent, or incompletely resectable disease. In this case, however, gross excision and synovectomy were achieved without postoperative radiotherapy or systemic antitumor therapy, with management transitioning instead to clinical and imaging surveillance.

The recovery course was largely favorable, punctuated by one unrelated complication. The patient experienced marked pain relief immediately after surgery, but on postoperative day three he developed fever, mild cough, and fatigue. Chest CT revealed bilateral patchy opacities, pulmonary infection was diagnosed, and intravenous cefuroxime with supportive care normalized his temperature and resolved his systemic symptoms. Follow-up imaging told a reassuring story: CT on the first postoperative day showed satisfactory filling of the acetabular defect by the bone graft, and at two months the graft maintained its position with osseous incorporation and healing. At the two-week mark the incision was well healed and hip motion had improved beyond preoperative levels. By six months, the patient reported sustained pain improvement and had returned to independent daily activities and work, although mild limitation of right hip motion persisted.

The case, reported in Cancer Reports, carries an educational message that resonates well beyond a single patient. Because the hip joint is deeply situated and its capsule has limited capacity to accommodate proliferative synovium, osseous erosion is a recognized feature of hip D-TGCT — yet a destructive-appearing acetabular lesion inevitably raises concern for septic arthritis, inflammatory synovitis, synovial chondromatosis, or a more aggressive neoplasm. The authors emphasize that MRI remains the preferred modality for mapping the extent of synovial disease, while CT more clearly delineates the osseous erosion relevant to operative planning, making the two techniques complementary rather than interchangeable. Ultimately, imaging alone could not reliably distinguish this tumor from infectious or aggressive etiologies; definitive diagnosis depended on integrating the clinical course, intraoperative observations, and characteristic histopathologic features. The authors frame the report primarily as an educational account of diagnostic evaluation and multidisciplinary management rather than evidence of durable local control, noting that the follow-up period remains short and that recurrence is a recognized concern given the complex anatomy of the hip. Longer surveillance will be needed to assess recurrence, joint function, and treatment durability. The broader lesson stands: diffuse-type tenosynovial giant cell tumor deserves a place on the differential diagnosis of any unexplained erosive intra-articular hip lesion, even when the clinical context screams infection.

Subject of Research: Diffuse-type tenosynovial giant cell tumor of the hip with acetabular bone involvement diagnosed by radiologic-pathologic correlation.

Article Title: Diffuse‐Type Tenosynovial Giant Cell Tumor of the Hip With Acetabular Bone Involvement: A Case Report With Radiologic‐Pathologic Correlation

Article References: Quanbing, W., Huanhuan, X., Xing, Z., Tao, Y., Jun, Z., Lei, Z., Kai, L., Lei, L., Feng, A., & Wei, Y. (2026). Diffuse‐Type Tenosynovial Giant Cell Tumor of the Hip With Acetabular Bone Involvement: A Case Report With Radiologic‐Pathologic Correlation. Cancer Reports, 9(9), Article e70696. https://doi.org/10.1002/cnr2.70696

Image Credits: AI Generated

DOI: 10.1002/cnr2.70696

Keywords: tenosynovial giant cell tumor, diffuse-type TGCT, hip, acetabular erosion, MRI, CT, synovectomy, histopathology, CSF1, case report, orthopedic oncology, diagnostic imaging

The review team searched three major biomedical databases, SCOPUS, PubMed, and Web of Science, and identified 129 records for consideration. After screening, 41 studies met the criteria for inclusion and provided usable data on disease type, imaging modalities, and reported radiation dose metrics. The populations covered were diverse: children with congenital heart disease, scoliosis, cystic fibrosis, inflammatory bowel disease, esophageal atresia, osteogenesis imperfecta, spina bifida, hydrocephalus, urological conditions, bleeding disorders, craniosynostosis, cleft palate, asthma, pulmonary hypertension, and organ transplant recipients, among others. This breadth is important, because the authors found that radiation exposure was not uniform across conditions but was strongly influenced by the specific diagnosis, the age at which imaging began, the severity of the disease, and the imaging modalities that each disease trajectory demands.

One of the clearest technical findings of the review is that the modality mix matters enormously. Plain radiography, the conventional X-ray, was by far the most frequently performed examination across nearly all chronic disease groups. However, radiographs deliver relatively small doses per examination, and the review concluded that they were not the dominant contributors to cumulative burden. Instead, computed tomography and fluoroscopy, both of which involve substantially higher dose outputs and, in the case of fluoroscopy, prolonged real-time exposure, accounted for the majority of the cumulative effective dose reported in the included studies. In some patient groups, cumulative doses from these higher-yield modalities exceeded 20 to 50 millisieverts, thresholds that radiation protection specialists regard as significant when accumulated during childhood.

The biological rationale for concern lies in the interaction between ionizing radiation and growing tissue. Effective dose, measured in millisieverts, is a calculated quantity that weights absorbed dose by the radiation sensitivity of the organs exposed, allowing comparison across different types of examinations. Pediatric patients are more sensitive to radiation-induced carcinogenesis than adults for several reasons: their tissues are actively dividing, their longer life expectancy leaves more time for radiation-induced cancers to manifest, and stochastic effects, meaning probabilistic DNA damage that may lead to malignancy decades later, do not have a known safe threshold in the linear no-threshold framework commonly used for protection purposes. A child with a chronic disease diagnosed in infancy may therefore face decades of potential risk following exposures delivered in the first years of life.

Several disease-specific patterns emerged from the included literature. Children with congenital heart disease, particularly those requiring staged surgical palliation or interventional cardiac catheterization, consistently appeared among the most heavily exposed groups, because cardiac fluoroscopy and CT angiography are central to both diagnosis and treatment. Studies cited in the review estimated cumulative doses during staged single-ventricle palliation and documented measurable chromosomal DNA damage in exposed children. In scoliosis management, repeated spinal radiographs required for curve monitoring, combined with intraoperative imaging, produced substantial cumulative exposure, prompting the development of low-dose slot-scanning systems that reduce dose compared with standard radiographs. Children with inflammatory bowel disease frequently underwent CT during acute flare-ups before magnetic resonance enterography became the preferred alternative, and retrospective cohorts documented cumulative doses high enough to raise malignancy concerns.

Other chronic conditions illustrated subtler but still meaningful exposure pathways. Infants with esophageal atresia undergo repeated contrast studies and fluoroscopic procedures in the first months of life, and one French study cited in the review explicitly asked how low these cumulative doses could realistically be pushed. Children with spina bifida and shunt-treated hydrocephalus accumulated exposure through serial imaging of the brain and spine, while pediatric stone disease generated exposure through fluoroscopy-guided procedures such as percutaneous nephrolithotomy and shockwave lithotripsy. Even conditions considered lower risk, such as developmental dysplasia of the hip, appeared in the literature, with one study reassuringly concluding that repeated pelvic radiographs during harness treatment carry very low radiation risk. Meanwhile, pediatric cleft palate patients showed a three- to five-fold increase in cumulative radiation exposure from dental radiology compared with age- and gender-matched peers.

Organ transplant recipients represent another group highlighted by the review. Children receiving heart transplants accumulated considerable exposure within the first post-transplant year through echocardiography-adjacent imaging, catheterization, and CT surveillance for complications such as rejection, infection, and vascular stenosis. A cohort study of pediatric transplant recipients more broadly documented diagnostic imaging exposure that was markedly elevated compared with healthy children. Similarly, children with osteogenesis imperfecta, the brittle bone disorder, required serial skeletal radiographs throughout childhood to monitor fractures and surgical interventions, with one cited study estimating associated lifetime cancer risk from these cumulative exposures.

What emerges from the synthesis is not a reason for alarm or for avoiding medically necessary imaging, the authors emphasize, but rather a roadmap for safer practice. The review calls for evidence-based referral guidelines specific to pediatric chronic disease populations, so that clinicians weigh the diagnostic yield of each examination against its dose contribution within the context of a child’s total imaging history. It also highlights the importance of standardized imaging protocols optimized for children, including weight- and age-based parameter adjustment, substitution of ultrasound or magnetic resonance imaging where diagnostically equivalent, and the use of dose modulation technologies in CT. Equally critical is dose reporting: recording cumulative effective dose in the patient record so that ordering physicians can see the full picture rather than evaluating each request in isolation. Principles such as ALARA, keeping exposure as low as reasonably achievable, and its extensions emphasizing appropriate use and avoiding unnecessary procedures, are framed as essential operational standards rather than abstract ideals.

The authors also point toward the practical infrastructure needed to make dose stewardship routine. Electronic health record integration of dose-tracking systems, standardized dose metrics across institutions, and education of referring clinicians about the relative doses of different modalities all feature in the review’s recommendations. International collaborative efforts, such as the HARMONIC project cohort studies on radiation exposure in children with congenital heart disease cited within the review, exemplify the kind of multinational, disease-stratified data collection the field needs to quantify risk precisely and track the impact of protection measures over time. The review itself was a literature-based analysis, so no individual patient data were collected, and no ethics approval was required.

For families, the message is one of partnership rather than fear. Parents of children with chronic diseases can and should ask whether each proposed imaging examination is necessary, whether a lower-dose alternative is available, and whether the child’s cumulative imaging history has been considered. For the medical community, the review consolidates more than a decade of evidence into a single argument: the child with a chronic disease is not a series of isolated imaging encounters but a single, longitudinally exposed patient whose total radiation burden deserves active management. As imaging technology continues to advance and dose reduction becomes increasingly feasible, the findings serve as both a benchmark of current exposure levels and a challenge to ensure that the children who depend most on medical imaging are also the best protected from its long-term consequences.

Subject of Research: Cumulative ionizing radiation exposure from medical imaging in pediatric patients with chronic diseases

Article Title: Cumulative ionizing radiation exposure in pediatric patients with chronic diseases: a narrative review

Article References: Eimane, A., Francavilla, M., Grigorjevs, A., Granata, C., Limantoro, I., Olteanu, B.-S., Sofia, C., Nievelstein, R. A., Kardos, M., Kasznia-Brown, J., Salerno, S., & Apine, I. (2026). Cumulative ionizing radiation exposure in pediatric patients with chronic diseases: a narrative review. Pediatric Radiology. https://doi.org/10.1007/s00247-026-06785-x

Image Credits: AI Generated

DOI: 10.1007/s00247-026-06785-x

Keywords: pediatric radiology, cumulative radiation dose, ionizing radiation, CT, fluoroscopy, radiation protection, chronic disease, effective dose, congenital heart disease, scoliosis, medical imaging, ALARA