Perineural invasion in intramedullary spinal cord metastasis

Animal models of brain and spinal cord metastases of NSCLC established using a brain stereotactic instrument

Objective

Animal models of brain and spinal cord metastases of non-small cell lung cancer were established through the intracranial injection of PC-9 Luc cells with a brain stereotaxic device. This method provides a reliable modeling method for studying brain and spinal cord metastases of non-small cell lung cancer.

Methods

PC-9 Luc cells at logarithmic growth stage were injected into the skulls of 5-week-old BALB/c nude mice at different cell volumes (30 × 104, 80 × 104) and different locations (using anterior fontanel as a location point, 1 mm from the coronal suture, and 1.5 mm from the sagittal suture on the right upper and right lower side of the skull). After 1 week of cell inoculation, fluorescence signals of tumor cells in the brain and spinal were detected using the IVIS Xenogen Imaging system. After 4 weeks, brain and spinal tissues from the nude mice were harvested. Following paraffin-embedded sectioning, HE staining was performed on the tissues.

Results

The fluorescence signals revealed that both brain and spinal cord metastasis occurred in the mice where the cells were injected at the lower right side of the skull. There was only brain metastasis in the nude mice injected with 30 × 104 cells at the upper right side of the skull. Both brain and spinal cord metastasis occurred in the nude mice injected with 80 × 104 cells. The HE staining revealed that both brain and spinal cord metastasis occurred in the mice injected with different amounts of PC-9 Luc cells, consistent with the results detected using the IVIS Xenogen Imaging system, thereby demonstrating the reliability of detecting fluorescent signals in vivo to determine tumor growth.

Conclusion

It is a reliable method to establish the animal model of brain and spinal cord metastases of non-small cell lung cancer by injecting different quantities of cells from different positions with a brain stereotaxic device. The IVIS Xenogen Imaging system has high reliability in detecting the fluorescence signals of brain and spinal cord metastatic tumors.

In search of zebras: Critical analysis of the rarity of perineural breast cancer spread to the brachial plexus in men

BACKGROUND

Perineural spread (PNS) of breast cancer to the brachial plexus is rare, with reports limited to cases only in female patients. This study aimed to determine the incidence of PNS in male compared with female patients.

METHODS

Adult breast cancer patients referred to a single institution between 1994 and 2022 were retrospectively reviewed for imaging or biopsy-confirmed cases of PNS to the brachial plexus. Two independent reviewers of articles published in any language between 1990 and 2022 in PubMed, Scopus, Embase, and Google Scholar performed a systematic literature review.

RESULTS

Of the 10,466 patients with breast cancer (10,355 female, 111 male) referred to a single institution, there were 42 female patients with PNS to the brachial plexus for an estimated incidence of 0.4%. In the same time period, there were 111 male patients treated for breast cancer, including 88 patients with Klinefelter's syndrome (KS); however, there were no cases of male patients with PNS. A systematic review of the world's literature did not identify male patients with PNS to the brachial plexus.

CONCLUSIONS

There is a lack of any reported cases of PNS of breast cancer to the brachial plexus in men or patients with KS, who have a much higher incidence of breast cancer. This may reflect either the compounding rarity of these two events or point toward a distinct hormonally-driven link between breast cancer and PNS, highlighted by the disparity in PNS incidence in men and women.

Impact of surgical treatment for intramedullary spinal cord metastasis on neurological function and survival: A multicenter retrospective study by the Neurospinal Society of Japan

BACKGROUND

This retrospective multicenter study aimed to analyze the characteristics and surgical outcomes of intramedullary spinal cord metastasis (ISCM) and to discuss the controversy regarding its surgical indications.

METHODS

This study included 29 ISCM patients who underwent surgery between 2009 and 2020. Biopsy cases were excluded from analysis. For functional and neurological functional assessments, Karnofsky Performance Status (KPS, %) and modified McCormick Scale (MMS, 5-grade scale) scores were determined before and after surgery. Patients were divided into two groups: a mild-to-moderate disability group with preoperative MMS grades 1 to 3, and a severe disability group with preoperative MMS grades 4 to 5.

RESULTS

The mean preoperative KPS was 45.9, and the mean duration from symptom onset to surgical intervention was 1 month. The ISCM was located in the cervical spine in 10 cases and the thoracic spine in 19 cases. The access route (myelotomy) for ISCM removal was via the posterior median sulcus in 9 cases and via the posterior lateral sulcus in 11 cases, while others were not recorded. The degree of removal was gross total resection in 20 patients (69%), subtotal resection in 0 patients, and partial removal in 9 patients (31%). No significant complications related to the surgical procedures were recorded. Postoperative adjuvant therapy included radiotherapy in 17 patients (58.6%) and chemotherapy or molecular targeted therapy in 13 patients (44.8%). Pathological findings of ISCM showed that colorectal cancer was the most common in 9 cases, followed by lung cancer in 7, renal cell carcinoma in 5, and breast cancer in 2. Twenty-one of the 29 patients (72.4%) were confirmed to have survived 6 months after surgery: 8 of the 10 patients (80%) in the mild-to-moderate disability group and 13 of the 19 patients (68.4%) in the severe disability group. At 6 months after surgery, 3 of the 8 patients (38%) in the mild-to-moderate group were able to maintain or improve their function. Eleven of the 13 patients (85%) in the severe disability group maintained their function despite being severely disabled.

CONCLUSIONS

This study suggests that surgical treatment can maintain or improve neurological function in a limited number of patients with ISCM, although it had minimal impact on improving the survival rate after surgery.

Perineural spread to the brachial plexus: a focused review of proposed mechanisms and described pathologies

BACKGROUND

Perineural spread (PNS) is an emerging mechanism for progressive, non-traumatic brachial plexopathy. We aim to summarize the pathologies (tumor and infection) shown to have spread along or to the brachial plexus, and identify the proposed mechanisms of perineural spread.

METHODS

A focused review of the literature was performed pertaining to pathologies with identified perineural spread to the brachial plexus.

RESULTS

We summarized pathologies currently reported to have PNS in the brachial plexus and offer a structure for understanding and describing these pathologies with respect to their interaction with the peripheral nervous system.

CONCLUSIONS

Perineural spread is an underrepresented entity in the literature, especially regarding the brachial plexus. It can occur via a primary or secondary mechanism based on the anatomy, and understanding this mechanism helps to support biopsies of sacrificial nerve contributions, leading to more effective and timely treatment plans for patients.