Highly malignant submandibular extraskeletal osteosarcoma in a young patient

A Rare Case of Extraosseous Osteosarcoma (EOS) of Parotid Gland

Extraosseous osteosarcoma is a rare malignant soft tissue neoplasm, and extraosseous osteosarcoma of the parotid gland is very rare. It has a very aggressive course, and there are no standardized treatment guidelines. We report the case of a 20 year old male patient who presented with history of right neck swelling since 6 years for which he had undergone right parotid surgery 5 years ago. The final histopathological report indicated that the mass was a pleomorphic adenoma. One year after the first surgery, the patient experienced recurrence of swelling over the operated site, and the size of the swelling has been increasing gradually since then. He was evaluated clinically, and a large mass was noted over the upper aspect of the right upper neck, extending to the occipital and parotid regions. An MRI scan was done which showed a 12 × 10 × 8 cm lesion centred in the right parotid gland, involving paraspinal muscles, C1-C2 vertebrae and extending into the parapharyngeal space. FNAC of the lesion showed features of pleomorphic adenoma. The patient underwent a complete excision of the tumour. The patient's post-operative period was uneventful. The final histopathological report of the patient was extraosseous osteosarcoma of the parotid gland. The patient was referred for adjuvant radiotherapy. He has been on regular follow-up for the past 6 months and has shown no sign of recurrence. EOS is an extremely rare tumour of the head and neck region which often requires extensive surgical resection with or without adjuvant radiotherapy. It has a high rate of local recurrence and a very low disease free survival. Such patients should be kept on a close follow-up.

Update on MR Imaging of Soft Tissue Tumors of Head and Neck

This article reviews soft tissue tumors of the head and neck following the 2020 revision of WHO Classification of Soft Tissue and Bone Tumours. Common soft tissue tumors in the head and neck and tumors are discussed, along with newly added entities to the classification system. Salient clinical and imaging features that may allow for improved diagnostic accuracy or to narrow the imaging differential diagnosis are covered. Advanced imaging techniques are discussed, with a focus on diffusion-weighted and dynamic contrast imaging and their potential to help characterize soft tissue tumors and aid in distinguishing malignant from benign tumors.

Osteoblastic Extraosseous Osteosarcoma of the Neck

Extraosseous osteosarcoma as a primary tumor of the neck is exceedingly rare, with only a few cases reported to date. The most appropriate therapy is still under investigation. We report a case of an aggressive, right-sided, advanced-stage extraosseous osteosarcoma in a female patient. A 48-year-old woman presented with a right-sided infra-parotid mass encompassing neck regions II and III, measuring over 6 cm in craniocaudal diameter. She was initially treated by wide surgical resection. The definitive histopathologic diagnosis was osteoblastic extraosseous osteosarcoma. Computed tomography at initial presentation did not show signs of tumorous growth in other areas. The patient was treated with adjuvant chemoradiotherapy postoperatively. A local recurrence with intraspinal propagation was noted 4 months after surgery, and a second surgical attempt was made to remove the tumor. The disease recurred in the neck and spine 3 months after the second surgical procedure, and a final unsuccessful attempt at reducing the tumor mass was performed. The tumor site was reirradiated. The patient died of local disease propagation 3 months later. Extraosseous osteosarcoma of the neck is an extremely rare tumor, distinct from primary osteosarcoma of the bone, with a high rate of local recurrence and poor prognosis in advanced disease.

Soft tissue tumors of the head and neck: imaging-based review of the WHO classification

The World Health Organization (WHO) system for defining and classifying soft tissue tumors is usually applied to lesions that occur in the trunk and extremities, but it also provides an excellent framework for characterizing nonepithelial extraskeletal tumors of the head and neck. Although nonepithelial extraskeletal tumors are in the minority among head and neck lesions, they are by no means rare. The WHO classification system recognizes nine major types based on histologic differentiation: adipocytic, fibroblastic or myofibroblastic, fibrohistiocytic, smooth muscle, skeletal muscle, vascular, pericytic, and chondro-osseous tumors, as well as soft tissue tumors of uncertain differentiation. Tumors of each histologic type may be further subclassified on the basis of their biologic behavior as benign, intermediate (ie, having malignant potential), or malignant. Imaging plays an important role in the noninvasive diagnosis and characterization of nonepithelial soft tissue tumors of the head and neck, providing clues about tumor grade, composition, extent, and involvement of adjacent structures. Although the imaging characteristics of many such tumors are nonspecific, consideration of the clinical history in concert with the imaging findings may help limit the differential diagnosis or even allow reliable diagnosis of some of these tumors.

Extraosseous osteosarcoma in the neck

BACKGROUND

Extraosseous osteosarcoma arising in the head and neck region is an exceptional finding, with a few isolated cases informed in the literature. We report a new case of a large high-grade extraosseous osteosarcoma located in the neck.

CASE PRESENTATION

A 74 year-old woman with a tumor on the right side of the neck was treated by complete surgical resection. The histopathological diagnosis was osteoblastic extraosseous osteosarcoma. PET-CT scan disclosed no evidence of disease in other areas. Patient received adjuvant radiotherapy and after 3 months of follow-up tumor activity was detected in the cavernous sinus and the patient died of disease one month later.

CONCLUSION

Extraosseous osteosarcoma in head and neck region is exceptional, and incisional biopsy is the only method to establish a diagnosis and the one to differentiate it from other bone-producing soft tissue tumors. Surgery is the gold standard for treatment of extraosseous osteosarcoma.