Recurrent rectal cancer causing lumbosacral plexopathy with perineural spread to the spinal nerves and the sciatic nerve: An anatomic explanation

Identification of perineural invasion at imaging staging as a novel potential risk factor in rectal cancer: A case report

Treatment of rectal cancer has improved over the years thanks to a multidisciplinary approach. A correct staging has a fundamental role for risk stratification and to define the best treatment for each patient. Unfortunately, approximately 30% of patients with locally advanced rectal cancers will experience tumor recurrence. Thus, the identification of novel clinical-pathological and radiological prognostic factors represents an urgent unmet clinical need. Here we report the case of a patient with radically resected localized rectal cancer who developed an impressive early pelvic recurrence. To better understand the clinical scenario, we have studied the possible factors related to the aggressiveness of the disease. The only poor prognosticfactor that was evidenced at histological report was perineural invasion. Therefore, we questioned whether we could evaluate perineural invasion with imaging, similar to head and neck tumors. Learning from this clinical case, we believe that improving the risk stratification and radiology reporting is necessary to provide the best care for the patient and allow for a better prognosis prediction. Of course, our data should be considered as hypothesis generating and should be further investigated and validated in larger and prospective studies.

Redo Pelvic Surgery and Combined Metastectomy for Locally Recurrent Rectal Cancer with Known Oligometastatic Disease: A Multicentre Review

INTRODUCTION

Historically, surgical resection for patients with locally recurrent rectal cancer (LRRC) had been reserved for those without metastatic disease. 'Selective' patients with limited oligometastatic disease (OMD) (involving the liver and/or lung) are now increasingly being considered for resection, with favourable five-year survival rates.

METHODS

A retrospective analysis of consecutive patients undergoing multi-visceral pelvic resection of LRRC with their oligometastatic disease between 1 January 2015 and 31 August 2021 across four centres worldwide was performed. The data collected included disease characteristics, neoadjuvant therapy details, perioperative and oncological outcomes.

RESULTS

Fourteen participants with a mean age of 59 years were included. There was a female preponderance (n = 9). Nine patients had liver metastases, four had lung metastases and one had both lung and liver disease. The mean number of metastatic tumours was 1.5 +/- 0.85. R0 margins were obtained in 71.4% (n = 10) and 100% (n = 14) of pelvic exenteration and oligometastatic disease surgeries, respectively. Mean lymph node yield was 11.6 +/- 6.9 nodes, with positive nodes being found in 28.6% (n = 4) of cases. A single major morbidity was reported, with no perioperative deaths. At follow-up, the median disease-free survival and overall survival were 12.3 months (IQR 4.5-17.5 months) and 25.9 months (IQR 6.2-39.7 months), respectively.

CONCLUSIONS

Performing radical multi-visceral surgery for LRRC and distant oligometastatic disease appears to be feasible in appropriately selected patients that underwent good perioperative counselling.

Diagnostic value of proximal cutaneous nerve biopsy in brachial and lumbosacral plexus pathologies

BACKGROUND

Brachial and lumbosacral plexopathies can result from numerous non-traumatic etiologies, including those of inflammatory, autoimmune, or neoplastic origin, that often require nerve biopsy for diagnosis. The purpose of this study was to evaluate the diagnostic efficacy of medial antebrachial cutaneous nerve (MABC) and posterior femoral cutaneous nerve (PFCN) nerve biopsies in proximal brachial and lumbosacral plexus pathology.

METHOD

Patients undergoing MABC or PFCN nerve biopsies at a single institution were reviewed. Patient demographics, clinical diagnosis, symptom duration, intraoperative findings, post-operative complications, and pathology results were recorded. Biopsy results were classified as diagnostic, inconclusive, or negative based on the final pathology.

RESULTS

Thirty patients undergoing MABC biopsies in the proximal arm or axilla and five patients with PFCN biopsies in the thigh or buttock were included. MABC biopsies were diagnostic in 70% of cases overall and 85% diagnostic in cases where pre-operative MRI also demonstrated abnormalities in the MABC. PFCN biopsies were diagnostic in 60% of cases overall and in 100% of patients with abnormal pre-operative MRIs. There were no biopsy-related post-operative complications in either group.

CONCLUSIONS

In diagnosing non-traumatic etiologies of brachial and lumbosacral plexopathies, proximal biopsies of the MABC and PFCN provide high diagnostic value with low donor morbidity.

The spectrum of brachial plexopathy from perineural spread of breast cancer

OBJECTIVE

Perineural spread of breast cancer to the brachial plexus can lead to pain, sensory alterations, and upper-extremity weakness. Although rare, perineural spread is an often-misdiagnosed long-term complication following breast cancer diagnosis. The objective of this study was to critically review the clinical, radiological, and pathological findings of biopsy-proven perineural spread of breast cancer to the brachial plexus.

METHODS

This is a retrospective study from a single institution in which a total of 19 patients with brachial plexus involvement from perineural spread of breast cancer who underwent fascicular biopsy between 1999 and 2021 were identified. Clinical, radiographic, and pathological data were retrospectively collected. Descriptive statistics were calculated for the cohort.

RESULTS

The mean age of patients at the time of diagnosis of breast cancer perineural spread was 60.6 ± 11.5 years. The diagnosis of brachial plexopathy due to perineural spread was on average 12 years after the primary diagnosis of breast cancer. There was also a delay in diagnosis due to the rarity of this disease, with a mean time from initial symptom onset to diagnosis of perineural spread of 25 ± 30 months. All patients at the time of presentation had upper-extremity weakness and pain. Nearly all patients demonstrated T2 signal change and nodular so-called sugar-coating contrast enhancement on brachial plexus MRI. Similarly, all patients who underwent PET/MRI or PET/CT had increased FDG uptake in the involved brachial plexus. Breast cancer perineural spread has an overall poor prognosis, with 16 of 19 patients dying within 5.9 ± 3.0 years after diagnosis of perineural spread.

CONCLUSIONS

Perineural spread should be considered in patients with a history of breast cancer, even 10 years after primary diagnosis, especially in patients who present with arm pain, weakness, and/or sensory changes. Further diagnostic workup with electrodiagnostic studies; brachial plexus MRI, PET/CT, or PET/MRI; and possibly nerve biopsy is warranted to ensure accurate diagnosis.

Lumbosacral plexopathy caused by the perineural spread of pelvic malignancies: clinical aspects and imaging patterns

BACKGROUND

Perineural spread (PNS) of tumors from pelvic malignancies is a rare phenomenon but constitutes an important differential diagnosis of lumbosacral plexopathy (LSP). Herein, we describe the clinical and imaging features of patients with LSP due to PNS of pelvic malignancies along with a literature review.

METHODS

We retrospectively reviewed 9 cases of LSP caused by PNS of pelvic malignancy between January 2006 and August 2021, and all clinical and imaging parameters were recorded in detail. Clinical symptoms and signs of patients were described and listed in the order in which they occurred. The results of imaging test were analyzed to describe specific findings in LSP caused by PNS.

RESULTS

This study enrolled nine adult patients (mean age, 50.1 years). Two cases initially presented as LSP and were later diagnosed with pelvic malignancy. Pain in the perianal or inguinal area preceded pain at the extremities in six patients. Neurogenic bladder or bowel symptoms developed in five patients. On the magnetic resonance imaging (MRI), the S1-S2 spinal nerve was most commonly involved, and S1 myotome weakness was more prominent in six patients than the other myotomes. One patient had an intradural extension. ¹⁸F-Fluorodeoxyglucose (FDG) positron emission tomography (PET) and computed tomography (CT) showed abnormal signal intensity in six patients. No abnormality in ¹⁸F-FDG PET/CT was detected in the nervous structures in one patient. Only four patients survived until the last follow-up visit.

CONCLUSIONS

Though rare, physicians should always keep in mind the possibility of LSP due to the PNS in patients with pelvic malignancy. Thorough physical examination and history taking could provide clues for diagnosis. Pelvic MRI and ¹⁸F-FDG-PET/CT should be considered for patients with LSP to rule out neoplastic LSP.

Sacral plexus disorder caused by a wooden toothpick in the rectum

A 67-year-old man presented with a 2-month history of pain in his right buttock and lower limb. MRI depicted right L5/S1 lateral recess stenosis requiring surgical treatment; however, preoperative CT showed an approximately 7 cm long, thin, rod-shaped structure in the rectum, which was ultimately determined to be an accidentally ingested toothpick. It was removed surgically 6 days after diagnosis, because right leg pain worsened rapidly. The pain disappeared thereafter, and the symptoms have not recurred since. The pain might have been localised to the right buttock and posterior thigh in the early stages because the fine tip of the toothpick was positioned to the right of the anterior ramus of the S2 spinal nerve. Although sacral plexus disorder caused by a rectal foreign body is extremely rare, physicians should be mindful to avoid misdiagnosis.

Imaging of non-neurogenic peripheral nerve malignancy-a case series and systematic review

OBJECTIVE

To evaluate the frequency, clinico-pathologic and imaging features of malignant tumors in peripheral nerves which are of non-neurogenic origin (non-neurogenic peripheral nerve malignancy-PNM).

MATERIALS AND METHODS

We retrospectively reviewed our pathology database for malignant peripheral nerve tumors from 07/2014-07/2019 and performed a systematic review. Exclusion criteria were malignant peripheral nerve sheath tumor (MPNST). Clinico-pathologic and imaging features, apparent diffusion coefficient (ADC_min), and standard uptake values (SUV_max) are reported.

RESULTS

After exclusion of all neurogenic tumors (benign = 196, MPNST = 57), our search yielded 19 non-neurogenic PNMs (7%, n = 19/272), due to primary intraneural malignancy (16%, n = 3/19) and secondary perineural invasion from an adjacent malignancy (16%, n = 3/19) or metastatic disease (63%, n = 12/19). Non-neurogenic PNMs were located in the lumbosacral plexus/sciatic nerves (47%, n = 9/19), brachial plexus (32%, n = 6/19), femoral nerve (5%, n = 1/19), tibial nerve (5%, n = 1/19), ulnar nerve (5%, n = 1/19), and radial nerve (5%, n = 1/19). On MRI (n = 14/19), non-neurogenic PNM tended to be small (< 5 cm, n = 10/14), isointense to muscle on T1-W (n = 14/14), hyperintense on T2-WI (n = 12/14), with enhancement (n = 12/12), low ADC_min (0.5-0.7 × 10-3 mm²/s), and variable metabolic activity (SUV_max range 2.1-13.1). A target sign was absent (n = 14/14) and fascicular sign was rarely present (n = 3/14). Systematic review revealed 89 cases of non-neurogenic PNM.

CONCLUSION

Non-neurogenic PNMs account for 7% of PNT in our series and occur due to metastases and primary intraneural malignancy. Although non-neurogenic PNMs exhibit a non-specific MRI appearance, they lack typical signs of neurogenic tumors such as the target sign. Quantitative imaging features identified by DWI (low ADC) and F¹⁸-FDG PET/CT (high SUV) may be helpful clues to the diagnosis.

Perineural Spread Along Spinal and Obturator Nerves in Primary Vaginal Carcinoma: A Case Report

BACKGROUND

Perineural spread is not an uncommon feature in carcinoma of the head and neck. On the contrary, perineural spread in pelvic malignancies has been rarely reported. This is the first report on perineural spread of the obturator nerve and the lumbosacral plexus from primary vaginal cancer.

CASE DESCRIPTION

A 50-year-old woman diagnosed with infectious spondylitis at an outside hospital was referred to our institution. She presented with persistent lower back pain and right anterior thigh pain. Magnetic resonance imaging and subsequent ¹⁸F-fluorodeoxyglucose-positron emission tomography/computed tomography revealed primary vaginal cancer with metastatic lymphadenopathy and perineural spread of the lumbosacral plexus, including L3, L4 nerve roots and branches, and obturator nerve along with soft tissue masses in the right psoas and proximal adductor muscles.

CONCLUSIONS

Clinical diagnosis of perineural spread in pelvic malignancies is difficult to establish, as it has nonspecific symptoms as an initial manifestation. Clinicians should recognize the possibility of perineural spread of malignancies if radiologic findings, such as thickening of lumbosacral nerves and perineural mass, are observed on magnetic resonance imaging. Further evaluation is necessary to detect possible pelvic malignancy and differentiate from other diseases.

Mathematical model of perineural tumor spread: a pilot study

BACKGROUND

Perineural spread (PNS) of pelvic cancer along the lumbosacral plexus is an emerging explanation for neoplastic lumbosacral plexopathy (nLSP) and an underestimated source of patient morbidity and mortality. Despite the increased incidence of PNS, these patients are often times a clinical conundrum-to diagnose and to treat. Building on previous results in modeling glioblastoma multiforme (GBM), we present a mathematical model for predicting the course and extent of the PNS of recurrent tumors.

METHODS

We created three-dimensional models of perineurally spreading tumor along the lumbosacral plexus from consecutive magnetic resonance imaging scans of two patients (one each with prostate cancer and cervical cancer). We adapted and applied a previously reported mathematical model of GBM to progression of tumor growth along the nerves on an anatomical model obtained from a healthy subject.

RESULTS

We were able to successfully model and visualize perineurally spreading pelvic cancer in two patients; average growth rates were 60.7 mm/year for subject 1 and 129 mm/year for subject 2. The model correlated well with extent of PNS on MRI scans at given time points.

CONCLUSIONS

This is the first attempt to model perineural tumor spread and we believe that it provides a glimpse into the future of disease progression monitoring. Every tumor and every patient are different, and the possibility to report treatment response using a unified scale-as "days gained"-will be a necessity in the era of individualized medicine. We hope our work will serve as a springboard for future connections between mathematics and medicine.

'Trident sign' in pelvis: sinister sign with poor prognosis

The perineural spread of the cancer through the lumbosacral plexus gives an appearance of 'trident sign' on contrast-enhanced CT scan and MRI. It is associated with adverse survival rates and carries a poor prognostic value.

Perineural spread in pelvic malignancies can be an alternate explanation for pelvic bony metastases rather than hematogenous spread. A report of two cases

We propose that pelvic malignancies can spread to bone and cause bony metastases using nerves as conduits. We reviewed two cases of pelvic malignancy with perineural spread of bladder cancer and prostate cancer. In a patient with prostate cancer, we identified six lesions that were positive on the (11)C-choline PET/CT scan and MRI; in a patient with bladder cancer, we identified two lesions positive on the (18)F-deoxy-glucose PET/CT scan and MRI. We carefully reviewed the imaging studies, and using established sclerotome maps we identified spinal nerves supplying each of eight pelvic bony lesions. All these spinal nerves showed evidence of tumor infiltration with extension toward the affected bones. We theorize that perineural tumor spread may serve as an additional mechanism of pelvic osseous metastases in pelvic malignancies.

Perineural spread of pelvic malignancies to the lumbosacral plexus and beyond: clinical and imaging patterns

OBJECT

Perineural spread along pelvic autonomie nerves has emerged as a logical, anatomical explanation for selected cases of neoplastic lumbosacral plexopathy (LSP) in patients with prostate, bladder, rectal, and cervical cancer. The authors wondered whether common radiological and clinical patterns shared by various types of pelvic cancer exist.

METHODS

The authors retrospectively reviewed their institutional series of 17 cases concluded as perineural tumor spread. All available history, physical examination, electrodiagnostic studies, biopsy data and imaging studies, evidence of other metastatic disease, and follow-up were recorded in detail. The series was divided into 2 groups: cases with neoplastic lumbosacral plexopathy confirmed by biopsy (Group A) and cases included based on imaging characteristics despite the lack of biopsy or negative biopsy results (Group B).

RESULTS

Group A comprised 10 patients (mean age 69 years); 9 patients were symptomatic and 1 was asymptomatic. The L5–S1 spinal nerves and sciatic nerve were most frequently involved. Three patients had intradural extension. Seven patients were alive at last follow-up. Group B consisted of 7 patients (mean age 64 years); 4 patients were symptomatic, 2 were asymptomatic, and 1 had only imaging available. The L5–S1 spinal nerves and the sciatic nerve were most frequently involved. No patients had intradural extension. Four patients were alive at last follow-up.

CONCLUSIONS

The authors provide a unifying theory to explain lumbosacral plexopathy in select cases of various pelvic neoplasms. The tumor cells can use splanchnic nerves as conduits and spread from the end organ to the lumbosacral plexus. Tumor can continue to spread along osseous and muscle nerve branches, resulting in muscle and bone “metastases.” Radiological studies show a reproducible, although nonspecific pattern, and the same applies to clinical presentation.

Magnetic resonance imaging evidence for perineural spread of endometriosis to the lumbosacral plexus: report of 2 cases

Sciatic nerve endometriosis (EM) is a rare presentation of retroperitoneal EM. The authors present 2 cases of catamenial sciatica diagnosed as sciatic nerve EM. They propose that both cases can be explained by perineural spread of EM from the uterus to the sacral plexus along the pelvic autonomie nerves and then further distally to the sciatic nerve or proximally to the spinal nerves. This explanation is supported by MRI evidence in both cases. As a proof of concept, the authors retrieved and analyzed the original MRI studies of a case reported in the literature and found a similar pattern of spread. They believe that the imaging evidence of their institutional cases together with the outside case is a very compelling indication for perineural spread as a mechanism of EM of the nerve.