OBJECTIVE: Chondromyxoid fibroma (CMF) is a rare, benign bone tumour which arises primarily in young adults and is occasionally diagnostically challenging. Glutamate metabotropic receptor 1 (GRM1) gene encodes a metabotropic glutamate receptor and was recently shown to be up-regulated in chondromyxoid fibroma through gene fusion and promoter swapping. The aim of this study was to interrogate cases of CMF for the presence of GRM1 gene rearrangements, gene fusions and GRM1 protein overexpression.
RESULTS: Selected cases were subjected to testing by fluorescent in-situ hybridisation (FISH) with a GRM1 break-apart probe, a targeted RNA sequencing method and immunohistochemical study with an antibody to GRM1 protein. Two cases were subjected to whole transcriptomic sequencing. In 13 of 13 cases, GRM1 protein overexpression was detected by immunohistochemistry using the GRM1 antibody. Of the 12 cases successfully tested by FISH, nine of 12 showed GRM1 rearrangements by break-apart probe assay. Targeted RNA sequencing analysis did not detect gene fusions in any of the eight cases tested, but there was an increase in GRM1 mRNA expression in all eight cases. Two cases subjected to whole transcriptomic sequencing (WTS) showed elevated GRM1 expression and no gene fusions.
CONCLUSIONS: GRM1 gene rearrangements can be detected using FISH break-apart probes in approximately 75% of cases, and immunohistochemical detection of GRM1 protein over-expression is a sensitive diagnostic method. The gene fusion was not detected by targeted RNA sequencing, due most probably to the complexity of fusion mechanism, and is not yet a reliable method for confirming a diagnosis of CMF in the clinical setting.

Surgical treatment of chondromyxoid fibroma of ribs is described. The diagnosis was verified after histological analysis. The patient underwent resection of multinodular tumor of anterolateral thoracic wall invading abdominal cavity via thoracoabdominal access. Postoperative period was uneventful. This case demonstrates the need for total en-bloc resection of tumor with surrounding tissues. Surgery is the only effective method for these patients.
Описан редкий случай хирургического лечения хондромиксоидной фибромы ребер. Диагноз верифицирован окончательно после получения планового гистологического заключения. Пациентке выполнено удаление многоузловой опухоли переднебоковой грудной стенки, прорастающей в брюшную полость, из комбинированного торакоабдоминального доступа. Послеоперационный период протекал без осложнений. Представленный случай демонстрирует необходимость радикального удаления опухоли с окружающими тканями единым блоком. Данные литературы демонстрируют, что единственным эффективным методом лечения данной категории пациентов является хирургический метод.

UNASSIGNED: Chondromyxoid fibroma (CMF) is a rare cartilaginous tumor, accounting for < 1% of benign bone tumors. We report a case of temporomandibular joint (TMJ)-CMF, involving the pterygopalatine space and skull base and discuss its epidemiology, clinical characteristics, and management.
UNASSIGNED: A 56-year-old woman presented with facial asymmetry and progressive mouth opening restriction due to a mass expanding upwardly to the auriculotemporal region. Using digital techniques to determine the lesion\'s boundary and reconstruct the normal glenoid fossa, the temporalis myofascial flap was transplanted between the titanium mesh and condyle to reconstruct the disc after tumor resection.
UNASSIGNED: This case highlights the importance of identifying patients with TMJ-CMF.

The clinical, radiological, and histopathological features of chondromyxoid fibroma can sometimes resemble those of other benign or malignant tumors. Recently, recurrent GRM1 rearrangements have been identified in chondromyxoid fibroma, and GRM1 positivity by immunohistochemistry has emerged as a dependable surrogate marker for this molecular alteration. Phosphaturic mesenchymal tumor is a rare tumor that often exhibits overexpression of fibroblastic growth factor 23 (FGF23) through various mechanisms. In this report, we present a case of GRM1-rearranged chondromyxoid fibroma that also exhibited FGF23 expression via in situ hybridization, posing significant diagnostic challenges during workup of the initial core biopsy. We hope that this case can serve as an educational resource, shedding light on a rare diagnostic pitfall.

Chondromyxoid fibroma is one of the rarest bone tumours, occurring most frequently in adult men in their second and third decades. It generally affects the metaphysis of long bones, particularly the femur and tibia. Diagnosis can pose differential challenges with various tumor types, particularly chondrosarcoma, requiring separate management. We present a case of chondromyxoid fibroma of the distal tibia detected by soft tissue swelling. Clinical, epidemiological and radiological aspects will be discussed.

Chondromyxoid fibroma (CMF) is a rarely documented benign osseous neoplasm, particularly with respect to its incidence in the lumbar spinal region. CMF predominantly manifests in vertebral bodies, exhibiting atypical emergence in ancillary anatomical sites. The present report describes, to the best of our knowledge, the second documented instance of CMF originating from the lumbar facet joint. The present case provides an example of CMF in the lumbar facet joint precipitating spinal canal stenosis, thereby engendering neurological manifestations in the lower extremities due to neoplastic proliferation through the intervertebral foramen. The present therapeutic intervention entailed surgical excision of the neoplasm concomitant with facet joint arthrodesis, with the objective of achieving comprehensive neoplasm eradication, ameliorating the symptomatology and safeguarding the spinal structural integrity of the patient. The present study aimed to illustrate the clinical implications of this rare neoplasm, thereby elucidating the diagnostic quandaries and therapeutic complexities associated with CMF in the lumbar facet joint. In addition, the present study aimed to augment the existing knowledge for the diagnosis and clinical management of CMF.

Chondromyxoid fibroma is a rare, benign tumor of the bone with excellent prognosis but a high rate of recurrence. We report a patient presenting with pain and a history of chondromyxoid fibroma of the distal left femur previously treated with multiple prior curettage and bone graft procedures. Magnetic resonance imaging and histopathology indicated a recurrence of tumor. Due to the small size of the tumor recurrence and challenges associated with prior open surgery, the patient underwent cryoablation of the lesion with computed tomography guidance. Follow-up 18 months later indicated a resolution of pain and improvement on magnetic resonance imaging, and no concerns after 20 months. To our knowledge, this is the first reported case of chondromyxoid fibroma treated with cryoablation. This case suggests cryoablation could be considered in the setting of recurrent chondromyxoid fibroma for local tumor control.

UNASSIGNED: Chondromyxoid fibroma (CMF) is an uncommon bone tumor, accounting for <1% of all bone tumors. It generally affects the metaphysis of the long bone of the lower limb and seldom involves the small bones, but the involvement of the flat bones, like ribs, is infrequent.
UNASSIGNED: A teenage girl complained of pain on the right side of the chest for the past 6 months, dull aching, and persistent without any diurnal variation. The chest X-ray examination showed a nodular, hyperdense lesion on the lateral chest wall near the 5-7th rib on the right side. A computed tomography scan confirmed the lesion from the sixth rib with ground-glass matrix and cortical thinning with a smooth margin, without any soft-tissue involvement. An enblock excision of the lesion was done. Histopathological studies showed a well-circumscribed tumor with reactive bone formation at the periphery with lobules of chondromyxoid tissue separated by spindle cells and stellate-shaped cells suggestive of CMF. At 1-year follow-up, she is asymptomatic without any recurrence.
UNASSIGNED: CMFs are rare benign tumors that require histopathological study to differentiate from other benign lesions of the bone. In flat tubular bones like the ribs, enblock resection is the mainstay of treatment.

Chondromyxoid fibroma is an unusual, benign bone tumour that is usually sited in the metaphyseal region of the long bones. It accounts for less than 1% of all bone tumours. It manifests predominantly in males in their second and third decades of life. Rarely, it occurs in the bones of the craniofacial skeleton. For small, lesions enucleation and curettage and for larger lesions, resection followed by are the treatment modalities available. Here, we present a case of chondromyxoid fibroma with respect to the right side of the mandible which was managed by surgical resection followed by reconstruction under general anaesthesia. Resection followed by reconstruction provides satisfactory outcomes, especially in cases with large lesions. Chondromyxoid fibroma is an asymptomatic, benign, slow-growing lesion but can rapidly expand and involve the greater area of bone. Thus, its detection at an early stage and treatment at the proper time can lead to less morbidity associated with the lesion and improved quality of life of the patient.

Chondromyxoid fibroma (CMF) is a rare benign bone tumour. While CMF located entirely on the surface of a bone (i.e. juxtacortical CMF) has been well characterised, CMF has not so far been convincingly documented to arise in soft tissues without connection to an underlying bone.We report a subcutaneous CMF in a 34-year-old male, located on the distal medial aspect of the right thigh without any connection with the femur. The tumour measured 15 mm, it was well-circumscribed and displayed typical morphological features of a CMF. At the periphery, there was a small area of metaplastic bone. Immunohistochemically, the tumour cells were diffusely positive for smooth muscle actin and GRM1, and negative for S100 protein, desmin and cytokeratin AE1AE3. Whole transcriptome sequencing revealed a novel PNISR::GRM1 gene fusion.Our case indicates that CMF should be included in the differential diagnosis of soft tissue (including subcutaneous) tumours composed of spindle/ovoid cells, with a lobular architecture and chondromyxoid matrix. The diagnosis of CMF arising in soft tissues can be confirmed by identifying a GRM1 gene fusion or GRM1 expression by immunohistochemistry.