Diagnostic utility of CSF1 immunohistochemistry in tenosynovial giant cell tumor for differentiating from giant cell-rich tumors and tumor-like lesions of bone and soft tissue

Diagnostic Challenge of Localized Tenosynovial Giant Cell Tumor in Children

This report describes a rare case of a pediatric tenosynovial giant cell tumor (TSGCT) with a delayed diagnosis. A 9-year-old boy presented with a 3-month history of knee pain and swelling, initially attributed to a femoral non-ossifying fibroma and arthritis based on computed tomography findings and slightly elevated C-reactive protein levels. The symptoms persisted despite medical treatment. Magnetic resonance imaging (MRI) revealed a tumor in the posterior compartment. He underwent surgery, and the pathology confirmed the diagnosis of localized TSGCT. Six months postoperatively, the patient remained asymptomatic. Pediatric knee pain is a complex symptom associated with inflammatory conditions and benign and malignant tumors. Benign tumors, as in this case, can be misdiagnosed as arthritis, delaying diagnosis and treatment. MRI is recommended in cases involving symptom persistence. However, histopathological, immunohistochemical, and morphological examinations are crucial for definitive diagnosis, particularly when the imaging findings are inconclusive.

Pathology of intra-articular tumours and tumour-like lesions: pearls, pitfalls and rarities from a general surgical pathology practice

Intra-articular tumours are uncommonly encountered in routine practice and may present diagnostic challenges to pathologists. Challenges unique to this site include distinction from more common reactive synovial conditions, which are far more common; histologic variability; superimposed reactive changes; and often, lack of provided clinicoradiological context. This article reviews the pathology of the synovial tumours and tumour-like lesions, including diagnostic pearls, pitfalls and rare entities.

Diffuse-type tenosynovial giant cell tumor between the suboccipital bone and posterior C1 arch: illustrative case

BACKGROUND

Tenosynovial giant cell tumor (TGCT) occurs most commonly in the appendicular skeleton and is only rarely found in the vertebral column. Lesions of the craniocervical junction are particularly rare, with only 4 cases reported in the literature. The authors describe the case of a diffuse-type TGCT at the craniocervical junction.

OBSERVATIONS

A patient presented with a 1-year history of right-sided neck pain and bilateral neurological symptoms in the distribution of the right occipital nerve. A 20-mm homogeneously contrast-enhancing mass in the suboccipital and posterior C1 region was discovered on magnetic resonance imaging of the cervical spine. The tumor was operated on via a posterior approach, and gross-total resection (GTR) was achieved. Immunohistochemical (IHC) examination revealed a diffuse-type TGCT. The patient had an uneventful recovery.

LESSONS

TGCT can arise at the craniocervical junction and is easily misdiagnosed because of its rare occurrence. IHC examination of a tumor specimen should be done to confirm the diagnosis. GTR is the objective when treating these tumors, especially when they are the diffuse type, as they have a high recurrence rate. Radiation and small-molecule therapies are viable postoperative therapies if GTR cannot be achieved or in cases of recurrence.