[Notochordal tumors : Benign notochordal tumors and chordomas]

Impact of CDK Inhibitors on TBXT Expression in Chordoma Cell Lines Including the First Stable Cell Line of a High-Grade Chordoma

Chordomas are very rare malignant neoplasms of the bone occurring almost exclusively along the spine. As the tumours are thought to arise from notochordal remnants, the vast majority of chordomas express the TBXT gene, resulting in detectable nuclear amounts of its gene product brachyury. This T-Box transcription factor is commonly recognised as being essential in chordoma cells, and limiting TBXT expression is thought to be the key factor in controlling this tumour. Although the tumour is rare, distinct molecular differences and vulnerabilities have been described with regard to its location and the progression status of the disease, rendering it mandatory for novel cell lines to reflect all relevant chordoma subtypes. Here, we describe a novel chordoma cell line arising from the pleural effusion of a disseminated, poorly differentiated chordoma. This cell line, U-CH22, represents a highly aggressive terminal chordoma and, therefore, fills a relevant gap within the panel of available cell culture models for this orphan disease. CDK7 and CDK9 inhibition was lately identified as being effective in reducing viability in four chordoma cell lines, most likely due to a reduction in brachyury levels. In this study, we determined the capability of the CDK7 inhibitor THZ1 and the CDK1/2/5/9 inhibitor dinaciclib to reduce TBXT expression at mRNA and protein levels in a broad range of nine cell lines that are models of primary, recurrent, and metastasised chordoma of the clivus and the sacrum.

Lumbar intraspinal microcystic/reticular schwannoma: Case report and literature review

RATIONALE

Microcystic/reticular schwannoma (MRS) is a rare histological variant of schwannoma which was initially described in 2008 with a predilection for the visceral organs. This distinct tumor had been reported to mainly affect gastrointestinal tract, subcutaneous and soft tissue, various glands and head and neck region. However, MRS involving spine is extremely rare.

PATIENT CONCERNS

The authors report the first case of MRS occurring in the lumbar (L) spinal canal of a 40-year-old male who presented with continuous pain and numbness in both feet for 2.5 years. Physical examination revealed weakness of lower extremities and hyperalgesia of both feet.

DIAGNOSES AND INTERVENTIONS

The findings of pre-operative investigation were suspicious for either a schwannoma or a spinal meningioma. Accordingly, total laminectomy, complete tumor resection, instrumentation and spinal fusion were performed. Post-operative histopathologic examination revealed a well-encapsulated neoplasm with reticular and microcystic growth pattern. Antoni A and Antoni B regions, Verocay bodies and hyalinized blood vessels were observed. And cytologic atypia, necrosis or mitosis was absent. Immunohistochemically, the tumor cells showed strong and diffuse positivity for S-100 as well as SOX 10. Therefore, a histopathological diagnosis of MRS was finally made.

OUTCOMES

The patient remains well with no evidence of recurrence at a 22-month follow-up.

LESSONS

This is the first case of MRS which is located in the L spinal canal. Awareness of this distinctive entity is helpful in preventing diagnostic pitfalls and making correct treatment strategies.