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.

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.

BACKGROUND: Chondromyxoid fibroma (CMF) is an unusual benign tumour of cartilaginous tissues that may be confused with other malignant tumours. It is rarely seen in the cervical spine.
METHODS: A 24-year-old young woman was admitted to the hospital because of neck and shoulder pain. Computed tomography, magnetic resonance imaging, X-ray and other imaging examinations of the cervical spine and laboratory-related indicators combined with intraoperative pathology revealed that the patient had cervical CMF. We performed total resection of the vertebral body and intervertebral disc, and internal fixation was performed to simultaneously maintain the stability of the entire spine. The clinical results from extensive resection were satisfactory. At the 2-year follow-up, the patient\'s symptoms had not recurred.
CONCLUSIONS: CMF is a benign primary bone tumour that is rarely located in the vertebral bone. Accurate initial diagnosis of these tumours is important for appropriate treatment. En bloc surgical resection of the tumour is the cornerstone of treatment.

The surgical resection of the tumor spreading into the cavernous sinus (CS) is complicated and challenging.
We report a left recurrent CS chondromyxoid fibroma occupying the clival-petrous apex-parasellar-suprasellar area, which was totally removed by the micro-endo combination technique via the middle cranial fossa extradural approach.
This case demonstrates the value of the micro-endoscopic combination technique for complicated skull base surgery.

OBJECTIVE: Whether H3.3 K36M mutation (H3K36M) could be an approach if the diagnosis of chondroblastoma (CB) patients was indistinct and it was suspected to be unclear clinically.
METHODS: We reviewed and compared our clinical experiences of CB cases and some suspected cases, which were not diagnosed distinctly, between 2013 to 2019. A total of 15 male and four female cases included in this study were seperated into two groups, CB group and suspected case (SC) group. The CB group included 13 men and 3 women, with an age range from 9 to 54 (mean age, 22 years old). The SC group included two men and one woman, with the age range from 13 to 25 (mean age, 19 years old). In both groups the patients had been followed-up until December 2019 and none of the patients had prior treatment history. We evaluated the clinical complaints, radiological features, and clinical-histological features of the cases and performed an immunohistochemical (IHC) study to detect whether the H3K36M expression of cases was different, consistent with a gene-mutation analysis.
RESULTS: In both groups, the radiologic features of both groups appeared as round low-density shadow with a clear edge, pathologic features showed diffuse proliferation of neoplastic cells with multinuclear giant cells. The radiological tumor size of CB group and SC group showed little difference, which was about 29.0*21.6 mm. Clinical-immunohistochemical features of both groups showed chondroid matrix inside with naïve tumor cells, multinucleated giant cells, and ground substance cells. Most of them showed chondro-related antibody positive (12 cases) but some of them showed S-100 negative (four cases). The clear difference of both groups was the result of H3K36M IHC study and gene analysis. In our cases, the CB group showed diffuse H3K36M positive and the SC group showed negative. The gene mutation analysis revealed that H3K36M-positive CB patients had K36M mutation, which were not found in the SC group. Sanger sequencing showed an A > T substitution at codon 36 of histone H3F3B. No other types of histone H3 mutation was detected in the CB group. Particularly, one of the suspected cases showed a G34W mutation was confirmed to be a giant cell tumor of bone (GCTB).
CONCLUSIONS: Our study showed H3K36M immunohistochemistry and gene mutation analysis were specific clinical diagnostic tools to distinguish suspected CB from other giant cell-rich or cartilage matrix-diffuse bone tumors. The clinical-radiological and histomorphological features of patients gave suggestions on whether the H3K36M IHC and gene analysis should be required.

BACKGROUND: Chondromyxoid fibroma-like osteosarcoma (CMF-OS) is an exceedingly rare subtype of low-grade central osteosarcoma (LGCO), accounting for up to 10% of cases and making it difficult to diagnose. CMF-OS is frequently misdiagnosed on a radiological examination and biopsy, even after the initial operation. Its treatment is a controversial issue due to its low-grade classification and actual high-grade behavior.
METHODS: We retrospectively reviewed the medical charts of more than 2000 osteosarcoma patients between 2008 and 2019; 11 patients with CMF-OS were identified, of which six patients were treated by our institution with complete clinical characteristics, including treatment and prognosis, radiological and pathological features were reviewed. Three males and three females with a median age of 46 (range 22-56) years were pathologically proven to have CMF-OS. The radiological presentation of CMF-OS is variable, thus radiological misdiagnoses are common. However, one must not ignore a malignant radiologic appearance. The most distinctive pathological feature conferring the diagnosis of CMF-OS is the presence of osteoid production directly by the tumor cells under a chondromyxoid fibroma (CMF)-like background. Differential diagnoses based on comprehensive data from CMF, LGCO, chondrosarcoma (CHS), conventional osteosarcoma (COS), etc., are needed. All patients were treated with an operation and chemotherapy, and one patient received additional radiotherapy. Nevertheless, recurrence and metastasis are common in CMF-OS patients. Relatively invasive biological behavior of CMF-OS is against the low-grade classification of this disease.
CONCLUSIONS: It is important to recognize CMF-OS and distinguish it from CMF, CHS, COS and other LGCOs. CMF-OS has a relatively poor prognosis despite its low-grade classification.

BACKGROUND: Chondromyxoid fibroma (CMF) is a rare benign bone tumour of cartilaginous origin, which usually affects the metaphysis of the long bone. Involvement of the temporal bone is extremely rare. Patients with CMF in the temporal bone can present some neurological deficits due to involvement of surrounding neural structures.
METHODS: We present the first case of histopathologically proven CMF originating in the temporal bone and involving the hypoglossal canal in a 40-year-old woman. Hypoglossal nerve paralysis was identified on the cranial nerve examination. The patient underwent surgical excision and was neurologically normal except for mild left facial palsy on 5-mo follow-up examination after surgery. In the current report, the major characteristics and computed tomography/magnetic resonance imaging features of the lesion are discussed. Furthermore, previous literature regarding this pathology is reviewed.
CONCLUSIONS: The current study presents the first case of temporal bone CMF involving the hypoglossal canal.

Chondromyxoid fibroma (CMF) is a rare benign bone tumor. This tumor mostly affects the long bones of the appendicular skeleton but rarely grows in the craniofacial region. In this article, a case of CMF of the mandible was presented to enhance our understanding of CMF. Its clinical manifestations, imaging characteristics, and treatment methods were discussed by analyzing the related literature.
软骨黏液样纤维瘤是一种罕见的良性骨肿瘤，通常较多见于四肢骨骼，而发生于颌面骨骼较为少见。软骨黏液样纤维瘤的临床表现以及影像学不具有特异性，易误诊为其他常见的骨肿瘤或肿瘤病变。本文报道1例发生于下颌骨的软骨黏液样纤维瘤，并结合相关文献对其临床表现、影像学特点及治疗方法等进行分析。.

We present a rare case of giant soap bubble-shaped cystic lesion in the craniofacial region in an adult female. Histopathologic examination revealed the tumor consisted of 3 components including chondroblastoma, chondromyxoid fibroma, and hemorrhagic aneurysmal bone cyst. The present case is rare in terms of size, location, and histopathologic diagnosis, which is probably the result of underdeveloped health care in the remote place.