天美传媒

Chondrosarcoma (CS) is a malignant tumor of chondroblast arises in the cortex or periosteum of metaphysis. They are relatively slow growing and have better prognosis. Secondary chondrosarcoma is a malignant chondroid tumor arising in a benign precursor. In cases of sporadic osteochondromas and multiple osteochondromas it will develop a secondary peripheral chondrosarcoma in 1% and 1%-3% cases respectively at the age of 30–60 years [1]. Patients with malignant chondrosarcomas typically present with a history of progressive pain and local swelling. The symptoms are usually insidious, progressive, and worse at night and have a long duration [2].

A 27 year old male presented with swelling over left leg ankle since 1 year which was rapidly increased in size in last 4 months. There was history of mild pain which was progressively increased.

Patient had history of surgical excision of mass lesion at same site 4 years back.

Radiological Findings Figures 1 and 2 CT scan-Ill-defined altered signal intensity lesion measuring 5.8 × 3.8 × 4.0 cm noted along lateral process of calcaneal tuberosity with well-defined soft tissue component.

Figure 1: CT scan-heterogeneously hypointense on T2 showing peripheral nodular enhancement with soft tissue involvement.

Figure 2: CT scan heterogeneously hypo-intense area showing peripheral nodular enhancement.

Signal characteristics of lesion are showed area of altered bone signal appearing hypointense on T1/T2 and showing heterogenous nodular peripheral enhancement is noted involving the lateral process of calcaneal tuberosity with bony outgrowth directed inferolaterally which is seen continuing with the parent bone (confirmed on CT). Extensive soft tissue appearing is to hypointense on T1 and heterogeneously hypointense on T2 showing peripheral nodular enhancement is noted continuing with the above mentioned lesion and is seen extending inferolaterally involving the adductor minimi muscle and plantar aponeurosis inferiorly; laterally seen extending upto skin surface and is seen displacing peroneus tendons anteriorly. Few areas of blooming noted in gradient sequence (CT-shows calcified matrix with in soft tissue) maximum thickness of soft tissue (2.4 cm). Another lesion with similar morphology and signal intensity is noted arising from superolateral aspect of calcaneal body measuring 2.5 × 2.3 × 2.4 cm. Area of altered bone signal intensity appearing hypointense on T1/T2/PDFS sequence noted involving medial portion of calcaneal body (chondroid matrix–confirmed on CT). Calcaneal bone shows diffuse marrow edema. Other visualized osseous structures show normal morphology and signal intensity. There was no evidence of any metastesis.

Findings suggestive of malignant bone lesion likely secondary chondrosarcoma.

Excision tissue sections studied showed a tumor composed of neoplastic chondrocytes arranged in lobules and sheets with infiltration into surrounding stroma (Figures 3 and 4). Neoplastic cells showed varying degree of nuclear atypia. Few of the bits showed more cellularity and nuclear atypia showing enlarged, pleomorphic nuclei, few showing nucleoli. Binucleated cells are also seen. Tumor showed cartilaginous matrix. There was no osteoid or bone formation by tumor cells was noted.the Histopathological report was given as in view of radiological features showing soft tissue extension and lesion size >5 cm, histomorphological features are suggestive of peripheral chondrosarcoma from lesion in left calcaneum.

Figure 3: Tumour composed of neoplastic chondrocytes arranged in lobules and sheets (H&E stain, 100x)

Figure 4: Tumor composed of neoplastic chondrocytes arranged in lobules and sheets with infiltration into surrounding stroma (H&E stain, 100 xs).

Chondrosarcoma (Cs) is a rare malignant cartilaginous tumor of the bone. Most arose from the medullary canal of the affected bone. CS of the calcaneum is a rare tumor of all over the bone.

CS can be primary or secondary type. CS that arise de novo are called primary whereas CS developing on preexisting benign cartilage tumors such as an enchondroma or osteochondroma are referred to as secondary CS [3]. In our case it is of secondary type. Secondary peripheral chondrosarcomas are malignant cartilage-producing tumors.

Depending on anatomic location CS is called central when they occur within the medullary canal or peripheral when they occur in the cartilage cap of an exostosis. In majorty of cases it develops from malignant change of enchondromas or the cartilaginous cap of osteochondromas.

The age commonly affected for CS is between the fourth and sixth decades of life. Patients of chondrosarcomas typically present with a history of progressive pain [4]. The site commonly noted is in the pelvis, scapula proximal femur, and shoulder girdle. The CS of small bones of hand and foot are rare [5,6]. The CS of the calcaneum is a rare lesion that accounts for 0.5%-2.97% of all CS of other sites. In the foot benign enchondromas, chondromyxoid fibromas and CS are the common tumor of all bone tumors. Radiographically, it can be difficult to distinguish low-grade chondrosarcomas from benign lesions. It is important to correlate radiological and clinicopathological features for the diagnosis of CS [7].

The radioimaging like radiography, computed tomography (CT) and Magnetic Resonance Imaging (MRI) are used to diagnosis calcaneal CS. On routine radiograph it will show osteolytic lesion with “rings or arc like” calcification of chondroid or cartilaginous matrix. Tumors shows reactive thickening of the cortex, or destroy the cortex forming a soft tissue mass lesion. The most common radiographic features of CS are endosteal scalloping, cortical expansion and cortical destruction. CT is essential for identifying the pattern of bone destruction and the presence of matrix mineralization.

While MRI is used for the extent of intraosseous and soft tissue involvement. Thus the radioimaging features are critical in diagnosis. The difficulty in differentiating enchondroma from low grade chondrosarcoma is well recognized and is even more difficult in small bones of the hands and feet.

The pathological criteria used for diagnosing CS include hypercellularity, double‐nucleated cells, cytologic atypia, myxoid change in the matrix, permeation within the bone, marrow spaces, and soft tissue extension. In our case on histopathology reported as in the view of radiological features showing soft tissue extension and lesion size >5 cm, histomorphological features are suggestive of peripheral chondrosarcoma calceneum.

On histopathological examination CS are of conventional, dedifferentiated, myxoid, mesenchymal, and clear cell type. Each neoplasm has a distinct histological morphology. The differential diagnosis is enchondroma, osteochondromas. For soft tissue extention and myxoid CS carefully look for chondromyxoid fibroma, Myxofibrosarcoma, Low grade fibromyxoid sarcoma [8].

More than 90% of conventional CSs are low to intermediate-grade tumors and should be distinguished from enchondroma. Permeation of cortical bone and/or preexisting medullary bone is most important to distinguish CSs from enchondromas.

The grading is primarily based on nuclear size, hyperchromasia, cellularity and mitoses Grade 1 (low-grade) Grade 2 (intermediate) tumors. Grade 3 (highgrade) tumors. Approximately 90% of conventional CSs are low to intermediate grade and rarely metastasize [9]. The CS location in foot is less aggressive nature comparison to other anatomic locations [10].

Treatment for chondrosarcoma

The therapy for chondrosarcoma remains surgical wide resection and chemotherapy. But the chemotherapy is less effective because of a low mitotic index and poor vascularity. The rate of local recurrence in secondary chondrosarcomas depends on adequate surgical treatment, its localization and histological grade. The average time between the initial diagnosis and malignant transformation was 9.8 years.

Secondary peripheral chondrosarcoma is the result of malignant transformation of a pre-existing osteochondroma.The rate of local recurrence in secondary chondrosarcomas depends on adequate surgical treatment, its localization and histological grade. We are presenting case for its clinical , radiological and histopathological findings.

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