Atypical Cartilaginous Tumors: Trends in Management

Incidental Finding of an Atypical Cartilaginous Tumor in an Adult Female with Recurrent Patellar Dislocation: Single-stage Extended Curettage using Freezing Nitrogen Ethanol Composite followed by Medial Patello-Femoral Ligament Reconstruction

Atypical cartilaginous tumor (ACT) refers to a low-grade cartilaginous neoplasm microscopically identical to grade 1 chondrosarcoma, affecting the appendicular skeleton. Treatment with intralesional curettage has been found to provide sufficient local control with less morbidity compared to wide resection. This is the first reported case of a simultaneous medial patello-femoral ligament (MPFL) reconstruction with extended curettage for ACT on the ipsilateral femur. A 45-year-old female presented with chronic recurrent patellar dislocation of the right knee. Magnetic resonance imaging revealed a tear of the MPFL, with an incidental epi-metaphyseal chondroid lesion. After biopsy confirmed an ACT, single-stage extended curettage using freezing nitrogen ethanol composite (FNEC) and MPFL reconstruction was performed, followed by augmentation with bone cement and a distal femoral plate. Currently, the patient is independently ambulatory, with full range of motion about the knee. Following histologic confirmation of an ACT in the setting of a concurrent MCL tear, a single-stage procedure to address both conditions is a viable option that can reduce complications associated with multiple surgeries. Extended curettage using FNEC has been shown to produce good short-term oncologic outcomes while maximizing function.

Emerging Treatments Targeting the Tumor Microenvironment for Advanced Chondrosarcoma

Chondrosarcoma (ChS), a malignant cartilage-producing tumor, is the second most frequently diagnosed osseous sarcoma after osteosarcoma. It represents a very heterogeneous group of malignant chemo- and radiation-resistant neoplasms, accounting for approximately 20% of all bone sarcomas. The majority of ChS patients have a good prognosis after a complete surgical resection, as these tumors grow slowly and rarely metastasize. Conversely, patients with inoperable disease, due to the tumor location, size, or metastases, represent a great clinical challenge. Despite several genetic and epigenetic alterations that have been described in distinct ChS subtypes, very few therapeutic options are currently available for ChS patients. Therefore, new prognostic factors for tumor progression as well as new treatment options have to be explored, especially for patients with unresectable or metastatic disease. Recent studies have shown that a correlation between immune infiltrate composition, tumor aggressiveness, and survival does exist in ChS patients. In addition, the intra-tumor microvessel density has been proven to be associated with aggressive clinical behavior and a high metastatic potential in ChS. This review will provide an insight into the ChS microenvironment, since immunotherapy and antiangiogenic agents are emerging as interesting therapeutic options for ChS patients.

Chondrosarcoma evaluation using hematein-based x-ray staining and high-resolution 3D micro-CT: a feasibility study

BACKGROUND

Chondrosarcomas are rare malignant bone tumors diagnosed by analyzing radiological images and histology of tissue biopsies and evaluating features such as matrix calcification, cortical destruction, trabecular penetration, and tumor cell entrapment.

METHODS

We retrospectively analyzed 16 cartilaginous tumor tissue samples from three patients (51-, 54-, and 70-year-old) diagnosed with a dedifferentiated chondrosarcoma at the femur, a moderately differentiated chondrosarcoma in the pelvis, and a predominantly moderately differentiated chondrosarcoma at the scapula, respectively. We combined a hematein-based x-ray staining with high-resolution three-dimensional (3D) microscopic x-ray computed tomography (micro-CT) for nondestructive 3D tumor assessment and tumor margin evaluation.

RESULTS

We detected trabecular entrapment on 3D micro-CT images and followed bone destruction throughout the volume. In addition to staining cell nuclei, hematein-based staining also improved the visualization of the tumor matrix, allowing for the distinction between the tumor and the bone marrow cavity. The hematein-based staining did not interfere with further conventional histology. There was a 5.97 ± 7.17% difference between the relative tumor area measured using micro-CT and histopathology (p = 0.806) (Pearson correlation coefficient r = 0.92, p = 0.009). Signal intensity in the tumor matrix (4.85 ± 2.94) was significantly higher in the stained samples compared to the unstained counterparts (1.92 ± 0.11, p = 0.002).

CONCLUSIONS

Using nondestructive 3D micro-CT, the simultaneous visualization of radiological and histopathological features is feasible.

RELEVANCE STATEMENT

3D micro-CT data supports modern radiological and histopathological investigations of human bone tumor specimens. It has the potential for being an integrative part of clinical preoperative diagnostics.

KEY POINTS

• Matrix calcifications are a relevant diagnostic feature of bone tumors. • Micro-CT detects all clinically diagnostic relevant features of x-ray-stained chondrosarcoma. • Micro-CT has the potential to be an integrative part of clinical diagnostics.

Prevalence and characteristics of benign cartilaginous tumours of the shoulder joint. An MRI-based study

OBJECTIVE

Enchondromas (EC) of the shoulder joint are benign intraosseous cartilage neoplasms, with atypical cartilaginous tumours (ACT) representing their intermediate counterpart. They are usually found incidentally on clinical imaging performed for other reasons. Thus far the prevalence of ECs of the shoulder has been analysed in only one study reaching a figure of 2.1%.

MATERIALS AND METHODS

The aim of the current study was to validate this number via retrospective analysis of a 45 times larger, uniform cohort consisting of 21.550 patients who had received an MRI of the shoulder at a single radiologic centre over a time span of 13.2 years.

RESULTS

Ninety-three of 21.550 patients presented with at least one cartilaginous tumour. Four patients showed two lesions at the same time resulting in a total number of 97 cartilage tumours (89 ECs [91.8%], 8 ACTs [8.2%]). Based on the 93 patients, the overall prevalence was 0.39% for ECs and 0.04% for ACTs. Mean size of the 97 ECs/ACTs was 2.3 ± 1.5 cm; most neoplasms were located in the proximal humerus (96.9%), in the metaphysis (60.8%) and peripherally (56.7%). Of all lesions, 94 tumours (96.9%) were located in the humerus and 3 (3.1%) in the scapula.

CONCLUSION

Frequency of EC/ACT of the shoulder joint appears to have been overestimated, with the current study revealing a prevalence of 0.43%.

Wait-and-scan: an alternative for curettage in atypical cartilaginous tumours of the long bones

Aims

Due to its indolent clinical behaviour, the treatment paradigm of atypical cartilaginous tumours (ACTs) in the long bones is slowly shifting from intralesional resection (curettage) and local adjuvants, towards active surveillance through wait-and-scan follow-up. In this retrospective cohort study performed in a tertiary referral centre, we studied the natural behaviour of ACT lesions by active surveillance with MRI. Clinical symptoms were not considered in the surveillance programme.

Methods

The aim of this study was to see whether active surveillance is safe regarding malignant degeneration and local progression. In total, 117 patients were evaluated with MRI assessing growth, cortical destruction, endosteal scalloping, periosteal reaction, relation to the cortex, and perilesional bone marrow oedema. Patients received up to six follow-up scans.

Results

At the time of the first follow-up MRI, 8% of the lesions showed growth (n = 9), 86% remained stable (101), and 6% decreased in size (n = 7). During the third follow-up, with a mean follow-up time of 60 months (SD 23), 24 patients were scanned, of whom 13% had lesions that had grown and 13% lesions that had decreased in size. After 96 months (SD 37), at the sixth follow-up MRI, 100% of the lesions remained stable. None of the lesions showed malignant progression and although some lesions grew in size (mean 1 mm (SD 0.8)), no malignant progression occurred.

Conclusion

We conclude that active surveillance with MRI is safe for ACTs in the long bones in the short- and mid-term follow-up.

A Masquerading Hematoma Resulting in the Delayed Diagnosis of a Soft Tissue Sarcoma: A Case Report

A 27-year-old male with insidious right arm swelling was diagnosed with a hematoma secondary to a partial biceps tear, later identified as a rhabdomyosarcoma. Soft tissue sarcomas (STS) may present with misleading patient histories and nonspecific symptoms, resulting in misdiagnosis and delayed treatment. One of the classic masqueraders of soft tissue sarcomas is hematomas secondary to trauma. Obtaining a prudent history with careful scrutiny of appropriate imaging often helps establish the correct diagnosis. Ultimately, tissue biopsy can resolve any ambiguous cases and prevent delays in diagnosis and treatment.

Chondroid Tumors: Review of Salient Imaging Features and Update on the WHO Classification

Chondrogenic tumors are typically well recognized on radiographs, but differentiation between benign and malignant cartilaginous lesions can be difficult both for the radiologist and for the pathologist. Diagnosis is based on a combination of clinical, radiological and histological findings. While treatment of benign lesions does not require surgery, the only curative treatment for chondrosarcoma is resection. This article (1) emphasizes the update of the WHO classification and its diagnostic and clinical effects; (2) describes the imaging features of the various types of cartilaginous tumors, highlighting findings that can help differentiate benign from malignant lesions; (3) presents differential diagnoses; and (4) provides pathologic correlation. We attempt to offer valuable clues in the approach to this vast entity.

Curettage or Resection? A Review on the Surgical Treatment of Low-Grade Chondrosarcomas

Introduction Low-grade chondrosarcomas (LG-CS), including atypical cartilaginous tumors (ACT), are locally aggressive lesions. The focus of the discussion sits on the differential diagnosis between benign lesions or aggressive cartilaginous tumors and on their treatment: intralesional curettage or wide resection. This study presents the results obtained in the surgical treatment of 21 cases of LG-CS. Methods This retrospective study includes 21 consecutive patients from a single center with LG-CS who underwent surgery from 2013 to 2021. Fourteen were located in the appendicular skeleton, and seven in the axial (shoulder blade, spine, or pelvis). Mortality rate, recurrence, metastatic disease, overall survival, recurrence-free survival, and metastatic disease-free survival were analyzed for each type of procedure and each disease location. Operative complications and residual tumors were also recorded in cases where resection was performed. Survival was calculated using the Kaplan-Meier method. Results Thirteen patients underwent intralesional curettage (11 appendicular and 2 axial lesions), and eight underwent wide resection (5 axial and 3 appendicular). There were six recurrences during the follow-up, 43% of the axial lesions recurred, rising to 100% in axial curetted ones. Appendicular LG-CS recurred in 21% of cases, and only 18% of curetted appendicular lesions were not eradicated. The overall survival for the entire follow-up is 90.5%, and the 5-year survival rate is 83% (12 patients have adequate follow-up). Recurrence-free and metastasis-free survival were higher in resection cases, with 75% and 87.5%, vs. curettage 69.2% and 76.9%, respectively. In 9% of cases, the preoperative biopsy was inconsistent with the pathology of the surgical specimen. Discussion LG-CS and ACT are described as having high survival and low potential for metastatic disease. For this reason, these lesions are subject to a change in treatment philosophy to reflect these characteristics. Intra-lesional curettage is advocated as a less invasive technique for eradicating atypical cartilage tumors and has fewer and less severe complications, which was in accordance with our findings. Diagnosis, however, is challenging; misgrading is frequent and should be considered. Because of this risk of under-treating higher-grade lesions, some authors still defend wide-resection as the treatment of choice. We observed a trend towards longer survival, less recurrence, and metastatic disease with wide resection. Metastatic disease was higher than expected, present in 19% of cases, and always associated with local recurrence. Conclusion LG-CS is still a diagnostic and treatment challenge; patient selection is fundamental. Overall survival is high, independent of treatment choice or lesion location. We found a higher rate of metastatic disease than described in the literature; this, coupled with a misgrading rate of 9%, reflects the difficulty of preoperative diagnosis and the risk of treating high-grade chondrosarcomas as a low-grade lesion. More studies should be carried out with larger samples to obtain statistically robust results.

Classification of Chondrosarcoma: From Characteristic to Challenging Imaging Findings

Chondrosarcomas can be classified into various forms according to the presence or absence of a precursor lesion, location, and histological subtype. The new 2020 World Health Organization (WHO) Classification of Tumors of Soft Tissue and Bone classifies chondrogenic bone tumors as benign, intermediate (locally aggressive), or malignant, and separates atypical cartilaginous tumors (ACTs) and chondrosarcoma grade 1 (CS1) as intermediate and malignant tumors. respectively. Furthermore, the classification categorizes chondrosarcomas (including ACT) into eight subtypes: central conventional (grade 1 vs. 2–3), secondary peripheral (grade 1 vs. 2–3), periosteal, dedifferentiated, mesenchymal, and clear cell chondrosarcoma. Most chondrosarcomas are the low-grade, primary central conventional type. The rarer subtypes include clear cell, mesenchymal, and dedifferentiated chondrosarcomas. Comprehensive analysis of the characteristic imaging findings can help differentiate various forms of chondrosarcomas. However, distinguishing low-grade chondrosarcomas from enchondromas or high-grade chondrosarcomas is radiologically and histopathologically challenging, even for experienced radiologists and pathologists.

Surgical Treatment of Bone Sarcoma

Bone sarcomas are rare primary malignant mesenchymal bone tumors. The three main entities are osteosarcoma, chondrosarcoma, and Ewing sarcoma. While prognosis has improved for affected patients over the past decades, bone sarcomas are still critical conditions that require an interdisciplinary diagnostic and therapeutic approach. While radiotherapy plays a role especially in Ewing sarcoma and chemotherapy in Ewing sarcoma and osteosarcoma, surgery remains the main pillar of treatment in all three entities. After complete tumor resection, the created bone defects need to be reconstructed. Possible strategies are implantation of allografts or autografts including vascularized bone grafts (e.g., of the fibula). Around the knee joint, rotationplasty can be performed or, as an alternative, the implantation of (expandable) megaprostheses can be performed. Challenges still associated with the implantation of foreign materials are aseptic loosening and infection. Future improvements may come with advances in 3D printing of individualized resection blades/implants, thus also securing safe tumor resection margins while at the same time shortening the required surgical time. Faster osseointegration and lower infection rates may possibly be achieved through more elaborate implant surface structures.