Primary orbital extraskeletal osteosarcoma and review of literature

Primary orbital sarcoma in adults: a case series with emphasis on post-irradiation sarcoma

PURPOSE

To describe a series of eight adult patients with primary orbital sarcoma and to review the existing literature on orbital sarcoma and post-irradiation sarcoma.

METHODS

Report of eight cases and literature review.

RESULTS

We report eight cases of primary orbital sarcoma, three of which were radiation-induced. Only one patient had a history of retinoblastoma. The most common presentations were painful proptosis and reduced vision. Most tumours arose in the extraconal compartment. The overall median age at diagnosis was 50 years. The pathology comprised a diverse group of tumours. Treatment and outcome varied between patients and their clinical circumstances.

CONCLUSIONS

Adult primary orbital sarcomas are rare. They can comprise a variety of tumour types and are difficult to treat. Irradiation is a significant risk factor, and the incidence of post-irradiation sarcoma of the orbit may be increasing due to the widespread use of radiotherapy and improved survival of patients with cancer. Post-irradiation sarcoma should be considered in the differential diagnosis of an orbital space-occupying lesion in a patient with a history of radiotherapy.

Extra-skeletal osteosarcoma: a review

Extra-skeletal osteosarcoma is a rare malignant soft tissue sarcoma which can cause a diagnostic challenge due to its non-specific presentation and soft tissue mineralisation, thus potentially mimicking conditions such as myositis ossificans. This review will outline the demographics, clinical presentation, key imaging features, differential diagnosis, management and outcomes of extra-skeletal osteosarcoma and serve as a reference to radiologists and other clinicians involved in the care of patients with soft tissue tumours and tumour-like lesions.

Ectopic Fibrous Dysplasia Presenting As a Well-Circumscribed Orbital Mass

The authors present the case of a middle-aged woman with subacute progressive swelling of the OD associated with pain and severely limited duction in all gazes. MRI demonstrated a ~3 cm circumscribed mass in the extraconal space, which displaced and distorted the globe and impinged upon ocular adnexa. She underwent lateral orbitotomy with bone osteotomy to remove the mass, and subsequent histopathologic examination showed woven bone set within a fibrotic background, microscopic features of fibrous dysplasia. Fibrous dysplasia is characterized by abnormal scar-like bony proliferation, typically within a preexisting structure of the skeletal system. To the authors' knowledge, this represents the first example of fibrous dysplasia presenting as an orbital mass unconnected to the craniofacial skeleton.

Computed tomography and magnetic resonance imaging of an unusual intraconal orbital osteoma

We report the case of a 64-year-old male patient with a 5 month history of proptosis, motility limitation and vision loss in OD. Visual acuity (VA) was 20/200 in OD and 20/20 in OS. CT showed a large, round, intraconal lesion, with bony density and no apparent connection to adjacent orbital walls. MRI showed a T1-weighted hypointense lesion surrounded by a contrast enhancing capsule. The orbital tumor was excised through a lateral orbitotomy revealing a nodular, round, osseous structure. Histological examination disclosed well-formed lamellar bone trabeculae, with no necrosis or mitosis figures. Immunohistochemical staining was negative for MDM2 and CDK4. After 3 years, there was no evidence of tumor recurrence and VA had improved to 20/30. Intraconal osteomas with no clear attachment to orbital walls are extremely rare. We are aware of a few reported cases in the lid, hand, thigh, tongue, pterygopalatine fossa and brain. To the authors' knowledge, this is the first report in English literature of an orbital intraconal osteoma without any visible relation to the orbital walls.

Lessons from Injury: How Nerve Injury Studies Reveal Basic Biological Mechanisms and Therapeutic Opportunities for Peripheral Nerve Diseases

Since Waller and Cajal in the nineteenth and early twentieth centuries, laboratory traumatic peripheral nerve injury studies have provided great insight into cellular and molecular mechanisms governing axon degeneration and the responses of Schwann cells, the major glial cell type of peripheral nerves. It is now evident that pathways underlying injury-induced axon degeneration and the Schwann cell injury-specific state, the repair Schwann cell, are relevant to many inherited and acquired disorders of peripheral nerves. This review provides a timely update on the molecular understanding of axon degeneration and formation of the repair Schwann cell. We discuss how nicotinamide mononucleotide adenylyltransferase 2 (NMNAT2) and sterile alpha TIR motif containing protein 1 (SARM1) are required for axon survival and degeneration, respectively, how transcription factor c-JUN is essential for the Schwann cell response to nerve injury and what each tells us about disease mechanisms and potential therapies. Human genetic association with NMNAT2 and SARM1 strongly suggests aberrant activation of programmed axon death in polyneuropathies and motor neuron disorders, respectively, and animal studies suggest wider involvement including in chemotherapy-induced and diabetic neuropathies. In repair Schwann cells, cJUN is aberrantly expressed in a wide variety of human acquired and inherited neuropathies. Animal models suggest it limits axon loss in both genetic and traumatic neuropathies, whereas in contrast, Schwann cell secreted Neuregulin-1 type 1 drives onion bulb pathology in CMT1A. Finally, we discuss opportunities for drug-based and gene therapies to prevent axon loss or manipulate the repair Schwann cell state to treat acquired and inherited neuropathies and neuronopathies.