Mathematical model of perineural tumor spread: a pilot study

Brachial plexopathy due to perineural tumor spread: a retrospective single-center experience of clinical manifestations, diagnosis, treatments, and outcomes

BACKGROUND

Perineural tumor spread (PNTS) to the brachial plexus (BP) is a rare and challenging condition. This study aimed to elucidate the clinical presentations, diagnostic challenges, and outcomes of patients with PNTS to the BP.

METHODS

We retrospectively reviewed patients diagnosed with PNTS to the BP at our institution between January 2009 and June 2024. Clinical characteristics, magnetic resonance imaging (MRI), 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) findings, and treatment outcomes were analyzed.

RESULTS

Seven patients (mean age, 50.3 years) were identified. The primary cancer diagnoses included invasive ductal carcinoma of the breast (n = 3), metaplastic carcinoma of the breast (n = 1), lung adenocarcinoma (n = 2), and papillary thyroid carcinoma (n = 1). The median time from the initial cancer diagnosis to PNTS symptom onset was 71.0 months. All patients initially presented with progressive unilateral pain or paresthesia, followed by motor weakness. Lower trunk plexopathy was the most common electrodiagnostic finding (n = 5). In most patients, BP MRI showed diffuse tubular enlargement and T2 hyperintensity throughout the BP (n = 6), with gadolinium enhancement primarily in the proximal regions (n = 7). 18F-FDG PET/CT demonstrated increased uptake in the BP, most prominently at the cervical spinal root or trunk levels (n = 6). Despite treatment, neurological outcomes were generally poor. Six of the seven patients died after a median follow-up of 19 months post-PNTS diagnosis.

CONCLUSIONS

PNTS to the BP can occur years after initial cancer diagnosis and may signify cancer progression. A high index of suspicion is crucial for timely diagnosis, particularly in patients with cancer and progressive upper extremity symptoms. Comprehensive imaging, including BP MRI and PET/CT, is essential for diagnosis. Despite treatment, prognosis remains poor, highlighting the need for improved diagnostic and therapeutic strategies.

ACR Appropriateness Criteria® Plexopathy: 2021 Update

Plexopathy may be caused by diverse pathologies, including trauma, nerve entrapment, neoplasm, inflammation, infection, autoimmune disease, hereditary disease, and idiopathic etiologies. For patients presenting with brachial or lumbosacral plexopathy, dedicated plexus MRI is the most appropriate initial imaging modality for all clinical scenarios and can identify processes both intrinsic and extrinsic to the nerves. Other imaging tests may be appropriate for initial imaging depending on the clinical scenario. This document addresses initial imaging strategies for brachial and lumbosacral plexopathy in the following clinical situations: nontraumatic plexopathy with no known malignancy, traumatic plexopathy (not perinatal), and plexopathy occurring in the context of a known malignancy or posttreatment syndrome. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Extensive perineural spread of an intrapelvic sciatic malignant peripheral nerve sheath tumor: a case report

Perineural spread has been described in multiple neoplasms of neural and non-neural origin. The peripheral nervous system may represent a highway by which tumors can spread throughout the body. Malignant peripheral nerve sheath tumor (MPNST) is a neoplasm arising from peripheral nerves with high rates of local recurrence and distant metastases, leading to a poor 5-year overall survival. In many cases, the optimal treatment involves wide en bloc excision with negative margins as well as chemotherapy and radiation. Even in cases of negative surgical margins, recurrence rates are high, suggesting possible skip lesions or very distant infiltration along the involved nerve. We report a case of high-grade MPNST of the sciatic nerve with post-mortem dissection and histopathologic characterization of perineural spread of microscopic disease to sites significantly proximal and distal to areas with evidence of gross disease, which may help to explain the high rates of local and distal recurrence in MPNST.