Fibrocartilaginous mesenchymoma: a clinicopathological analysis of four cases / 中华病理学杂志

Objective: To investigate the clinical, radiological, histological and molecular features and the differential diagnosis of fibrocartilaginous mesenchymoma (FM). Methods: Four cases of FM diagnosed in the Department of Pathology, the Sixth People's Hospital Affiliated to Shanghai Jiaotong University School of Medicine from 2020 to 2022 were analyzed. Related literature was also reviewed. Results: Case 1 was a 10-year-old girl with bone destruction in the sacrum and L5 articular processes revealed by CT scan. Case 2 was a 7-year-old girl with an aggressive lesion in her right distal ulna. Case 3 was an 11-year-old boy with a lesion in the metaphysis of his left proximal tibia. Case 4 was an 11-year-old boy with bone destruction in the distal portion of a radius. Microscopically, the four tumors all consisted of numerous spindle cells, hyaline cartilage nodules, and bone trabeculae. The hypocellular to moderately cellular spindle cell component contained elongated cells with slightly hyperchromatic, mildly atypical nuclei arranged in bundles or intersecting fascicles. Benign-appearing cartilaginous nodules of various sizes and shapes were scattered throughout the tumors. There were areas mimicking epiphyseal growth-plate characterized by chondrocytes arranged in parallel columns and areas of enchondral ossification. The stroma was rich in mucus in case 1. Mutation of GNAS and IDH1/IDH2 and amplification of MDM2 gene were not found in any of the three tested cases. Conclusions: FM is very rare and tends to affect young patients. It most frequently occurs in the metaphysis of long tubular bones, followed by the iliac-pubic bones and vertebrae. FM is characterized by a mixed population of spindle cells, hyaline cartilage nodules and trabeculae of bone, without specific immunophenotypes and molecular alternations. As a borderline, locally aggressive neoplasm, surgical removal with a wide margin is generally the treatment of choice for FM.

Monitoring Response to Neoadjuvant Chemotherapy of Primary Osteosarcoma Using Diffusion Kurtosis Magnetic Resonance Imaging: Initial Findings

OBJECTIVE: To determine whether diffusion kurtosis imaging (DKI) is effective in monitoring tumor response to neoadjuvant chemotherapy in patients with osteosarcoma. MATERIALS AND METHODS: Twenty-nine osteosarcoma patients (20 men and 9 women; mean age, 17.6 ± 7.8 years) who had undergone magnetic resonance imaging (MRI) and DKI before and after neoadjuvant chemotherapy were included. Tumor volume, apparent diffusion coefficient (ADC), mean diffusivity (MD), mean kurtosis (MK), and change ratio (ΔX) between pre- and post-treatment were calculated. Based on histologic response, the patients were divided into those with good response (≥ 90% necrosis, n = 12) and those with poor response (< 90% necrosis, n = 17). Several MRI parameters between the groups were compared using Student's t test. The correlation between image indexes and tumor necrosis was determined using Pearson's correlation, and diagnostic performance was compared using receiver operating characteristic curves. RESULTS: In good responders, MDpost, ADCpost, and MKpost values were significantly higher than in poor responders (p < 0.001, p < 0.001, and p = 0.042, respectively). The ΔMD and ΔADC were also significantly higher in good responders than in poor responders (p < 0.001 and p = 0.01, respectively). However, no significant difference was observed in ΔMK (p = 0.092). MDpost and ΔMD showed high correlations with tumor necrosis rate (r = 0.669 and r = 0.622, respectively), and MDpost had higher diagnostic performance than ADCpost (p = 0.037) and MKpost (p = 0.011). Similarly, ΔMD also showed higher diagnostic performance than ΔADC (p = 0.033) and ΔMK (p = 0.037). CONCLUSION: MD is a promising biomarker for monitoring tumor response to preoperative chemotherapy in patients with osteosarcoma.

Imaging manifestations and clinical diagnosis of phosphaturic mesenchymal tumor / 中华放射学杂志

Objective To investigate the clinical and imaging characteristics of phosphaturic mesenchymal tumor and improve the clinical diagnosis. Methods From November 2014 to September 2017, 22 patients with pathologically confirmed diagnosis as phosphaturic mesenchymal tumor (PMT) were retrospectively analyzed, including 12 males and 10 females, age ranged from 30-72 years, mean (47 ± 11) years old. The clinical data, laboratory tests [serum calcium, phosphorus, alkaline phosphatase, parathyroid hormone and 1, 25- (OH) 2 D] and imaging examinations (X-ray, CT, MRI, nuclide) were collected and explored. Sixteen patients underwent SPECT scan and seven underwent PET/CT scan. Twenty patients had X-ray, eighteen patients had CT and 12 patients had MRI with enhancement. Results All patients suffered from diffuse pain for one to fifteen years, especially in lower back and lower extremities. All patients were found with low serum phosphorus, normal serum calcium. Twenty-one patients were found with elevated alkaline phosphatase, 16 with increased parathyroid hormone and 15 with decreased 1, 25 - (OH) 2 D. Thirteen lesions were located in the medullary cavity, seven in the soft tissue and two in the sinuses. Nineteen cases showed varying degrees of trabecular bone sparse, osteoporosis and osteomalacia on X-ray;There were 15 cases of multiple pseudo-fractures, including four cases of pelvic fracture complicated with femoral fracture, six cases of single fracture of pelvis, four cases of femur and one case of fibula. And seven cases showed multiple vertebral compression fractures. Thirteen lesions showed soft-tissue density and four in the medullary cavity showed high density on CT scan. The lesions presented low signal intensity on T1WI,high or low signal intensity on T2WI FLAIR and obviously enhanced in 12 patients who underwent MRI enhancement. Conclusion For patients with decreased serum phosphorus, elevated alkaline phosphatase, bone softening and fracture, octreotide or other nuclides should be primary imaging modality for confirming the location of the lesion. CT and MRI can further evaluate the nature of the lesion and improve diagnostic accuracy.

Clinicopathologic characteristics of primary Schwannoma of the bone / 中华病理学杂志

<p><b>OBJECTIVE</b>To evaluate the diagnostic criteria and morphologic difference of primary schwannoma from that of soft tissue schwannoma.</p><p><b>METHODS</b>All neurogenic tumors of the bone in this hospital from 2002 to 2013 were reviewed, four cases of primary schwannoma arising from bone were selected. Their clinical features, radiologic appearance and pathologic findings were evaluated. Immunophenotyping was performed using EnVision method.</p><p><b>RESULTS</b>All four cases had classic morphologic features and immunophenotype of conventional schwannoma. Compared with schwannoma of the soft tissue, primary bone schwannoma had the following features: benign radiological appearance, absence of capsule under light microscope, local infiltration of bone or destruction of bone cortex, occasionally involving extra-osseous soft tissue. Most tumors were solid, with less cystic degeneration. Histologically, the tumors were mainly composed of compact areas of spindle cells (Antoni A), and areas of hypercellularity could often be observed.</p><p><b>CONCLUSIONS</b>Primary schwannoma of the bone is rare, usually arises within the long bones and flat bones. Compared to conventional soft tissue schwannoma, it shows different growth pattern, imaging and pathologic features; thus care should be exercised not to misdiagnose schwannoma of the bone as other primary low-grade malignant spindle cell sarcoma of the bone and to avoid unnecessary over-treatment.</p>