Case Report
Clinical features
82 year old male patient complains of pain and swelling in right elbow and since 31/2 months. Swelling was progressive in size. On examination swelling of size 3.5x3cm was located in right elbow, tenderness, inflammation and mild restriction of movement noted. Right elbow X-ray was taken which was reported as normal. Lesion was excised and sent for histopathological examination.
Pathology
Gross
Received grey white cystic soft tissue measuring 3x2.5x1.5 cm. Cut surface shows multiple cystic spaces filled with grey white gelatinous material.
Microscopy
H/E Section showed a neoplasm composed of multiple lobules showing extensive myxoid area with tumor cells arranged in sheets and trabecular pattern having round to oval nuclei showing moderate pleomorphism and eosinophilic cytoplasm. Increase in mitosis noted. It was reported as extra skeletal myxoid chondrosarcoma.
To confirm following panels of immunohistochemistry was employed which includes S100, Vimentin, NSE, Synaptophysin, CK and EMA. Of which vimentin showed positivity. All other markers were negative.
Discussion
EMC is an uncommon soft tissue sarcoma with chondroblastic origin but positivity of neuroendocrine or neural markers suggest likely neuroendocrine or neural differentiation in some Extraskeletal myxoid chondrosarcoma.3,4 Regardless of the name there is no substantial indication of cartilaginous differentiation.
It mostly occurs in adults, about 54 years. Males are affected more than female.5 It is more common in extremities.3 Occasionally occur in foot, trunk, head and neck and paraspinal, and region.6
Clinical features vary depending on their locations, EMC tumors present with nerve compression symptoms.7 Swelling, decreased mobility, pain tenderness.6
Radiologically shows an soft tissue mass with clear border and even density. The mass will have an lobulated appearance, and in T1WI it is hypoechoeic to muscle, but on T2WI hyperechoeic, and it is separated into several lobules by numerous septa which appears hypoechoeic.7
Grossly it is an Large mass with psuedocapsule, C/S- shows an well-defined multiple nodules with gelatinous areas separated by fibrous septa.
Microscopy shows a multinodular architecture with malignant chondroblast like cells arranged in clusters or cords in a myxoid matrix. There is no definite cartilaginous differentiation.
The neoplastic cells have moderate eosinophilic, finely granular to vacuolated cytoplasm and uniform round to oval nuclei and inconspicuous nucleoli. Mitotisis usually low.
Cellular variant – shows epithelioid cells with high mitosis and geographic necrosis along with that conventional EMC noted.
It is essential to differentiate EMC from other myxoid tumors and extraskeletal mesenchymal chondrosarcoma Immunohistochemistry shows reliable positivity for vimentin and shows positivity for SIOO, CK, EMA focally. Few cases shows positivity for NSE, Synaptophysin.5
Translocation t (9;22)(q22;q12) consistently has been identified in EMC.8,9
Conclusion
EMC shows increased incidence of tumor recurrence and distant spread in spite of a prolonged clinical course.10 The only therapeutic option for EMC is early wide local resection with or without radiation for localized disease.11 MRI alone cannot distinguish EMC from common extraskeletal chondrosarcoma. Therefore, diagnosing EMC with both CT and MRI scan is suggested.2
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