Neurolymphomatosis as primary presentation of extra-nodal NK/T-cell lymphoma, nasal type.

Neurolymphomatosis (NL) describes an infiltration of cranial and peripheral nerves by lymphoma cells, most frequently in non-Hodgkin B-cell lymphoma. This clinical entity is rare and poses a challenging diagnosis. We describe a case of a 64-year-old female patient with NL associated with extra-nodal NK/T-cell lymphoma (ENKTL), nasal type, presenting as a painful progressive mononeuropathy multiplex with an oral cavity lesion. ENKTL is usually associated with Epstein-Barr virus (EBV) infection and rarely affects the central and peripheral nervous system. Lumbar puncture, magnetic resonance imaging (MRI), nerve biopsy, and 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) help to establish the diagnosis. Thereby, NL should be considered in the differential diagnosis of painful progressive multiple neuropathies, even in patients without previous history of cancer.

Primary peripheral nerve lymphoma: a case report and literature review.

Neurolymphomatosis (NL) is an uncommon malignant lymphoma characterized by selective infiltration of the central and peripheral nervous system. In this case report, we present a patient diagnosed with diffuse large B-cell lymphoma who initially manifested with peripheral neuropathy, primarily characterized by weakness of the left lower limb. By exploring its clinical manifestations, ancillary tests, and reviewing the relevant literature, we aim to deepen our understanding, diagnosis, and treatment of this disease. A 48-year-old male patient presented to the Department of Neurology, Hematology, and Neurosurgery with complaint of left lower limb weakness that had persisted for over 11 months. Initial laboratory tests and cerebrospinal fluid analysis yielded negative results. Electromyography examination indicated damage to the left lumbar plexus and iliac plexus nerves raising suspicions of nerve root involvement. Enhanced MRI of the lumbosacral plexus nerves revealed thickening and enhanced signals in left nerve roots at T12-L1, L1-2, and L3-4 levels. Additionally, local thickening and enhancement of signals were observed in the left erector spine muscle, psoas major, and iliopsoas muscles compared to the contralateral side. PEC/CT imaging displayed multiple soft tissue density shadows in the left foraminal area at the T12-1 and L1-2 levels. Bone marrow examination excluded hematological disease. Subsequent biopsy of the left foraminal nerve root at T12-L1 and the vertebral muscle at L3 level confirmed a diagnosis of diffuse large B-cell malignant lymphoma, indicating PNSL due to the involvement of multiple nerve roots. Following diagnosis, the patient underwent chemotherapy, resulting in the alleviation of his symptoms. Diagnosing PNSL can be challenging due to the nonspecific clinical manifestations and often inconclusive laboratory test results. Misdiagnosis and delayed diagnosis are common pitfalls. Electromyography may reveal damage to the affected peripheral nerves, while MR imaging might show nerve root thickening, and PET/CT can demonstrate increased lesion uptake. However, the definitive diagnosis relies on a biopsy of the lesion. Treatment for PNSL typically involves chemotherapy.

Primary cauda equina lymphoma confirmed by autopsy: A case report.

Compared with those involving the central nervous system, lymphomas involving the peripheral nervous system, namely neurolymphomatosis, are extremely rare. Neurolymphomatosis is classified as primary or secondary; the former is much rarer than the latter. Herein, we present an autopsied case of primary cauda equina lymphoma (PCEL), a type of primary neurolymphomatosis, with a literature review of autopsied cases of PCEL as well as primary neurolymphomatosis other than PCEL (non-PCEL primary neurolymphomatosis). A 70-year-old woman presented with difficulty walking, followed by paraplegia and then bladder and bowel disturbance. On magnetic resonance imaging, the cauda equina was diffusely enlarged and enhanced with gadolinium. The brainstem and cerebellum were also enhanced with gadolinium along their surface. The differential diagnosis of the patient included meningeal tumors (other than lymphomas), lymphomas, or sarcoidosis. The biopsy of the cauda equina was planned for a definite diagnosis, but because the patient deteriorated so rapidly, it was not performed. Eventually, she was affected by cranial nerve palsies. With the definite diagnosis being undetermined, the patient died approximately 1.5 years after the onset of disesase. At autopsy, the cauda equina was replaced by a bulky mass composed of atypical B-lymphoid cells, consistent with diffuse large B-cell lymphoma (DLBCL). The spinal cord was heavily infiltrated, as were the spinal/cranial nerves and subarachnoid space. There was metastasis in the left adrenal. The patient was finally diagnosed postmortem as PCEL with a DLBCL phenotype. To date, there have been a limited number of autopsied cases of PCEL and non-PCEL primary neurolymphomatosis (nine cases in all, including ours). The diagnosis is, without exception, B-cell lymphoma including DLBCL, and the histology features central nervous system parenchymal infiltration, nerve root involvement, and subarachnoid dissemination (lymphomatous meningitis). Metastases are not uncommon. All clinicians and pathologists should be aware of lymphomas primarily involving the peripheral nervous system.

Pronator syndrome and anterior interosseous nerve palsy due to neurolymphomatosis: a case report.

Pronator syndrome is a median nerve entrapment neuropathy that can be difficult to diagnose due to its variable presentation and objective findings. Neurolymphomatosis is an uncommon disease in which malignant lymphocytes infiltrate central or peripheral nerve endoneurium and is often missed for prolonged periods prior to diagnosis. We present a rare case of pronator syndrome and anterior interosseous nerve palsy due to neurolymphomatosis that was occult on initial MRI in spite of the presence of a median nerve mass discovered intra-operatively during neurolysis. This case demonstrates the value of ultrasound for the examination of peripheral nerve pathology and illustrates its utility as an adjunct to MRI, in part due to the ability to screen a large region.

The role of 18F-FDG PET/CT in Neurolymphomatosis: A Comprehensive Imaging Approach.

Neurolymphomatosis (NL) is an uncommon and rare neurologic disorder characterised by extranodal lymphoma, where the tumour cells invade the cranial nerves, nerve plexus, nerve root, spinal nerve roots, trunk nerves or peripheral nerves. MRI is the modality of choice, but is often challenging in detection of early recurrence, assessing residual disease and response evaluation. 18FFDG PET/CT has superior diagnostic performance compared with body CT in the evaluation of NL. 18F-FDG PET-CT is helpful in evaluation of disease extent and potential to guide biopsy. 18F-FDG PETCT is a highly sensitive technique for early localisation of NL than MRI or CT alone. Besides diagnostic and prognostic value in NL, it might be very helpful in response assessment.

Primary perineuritis, a rare but treatable neuropathy: Review of perineurial anatomy, clinicopathological features, and differential diagnosis.

The perineurium surrounds each fascicle in peripheral nerves, forming part of the blood-nerve barrier. We describe its normal anatomy and function. "Perineuritis" refers to both a nonspecific histopathological finding and more specific clinicopathological entity, primary perineuritis (PP). Patients with PP are often assumed to have nonsystemic vasculitic neuropathy until nerve biopsy is performed. We systematically reviewed the literature on PP and developed a differential diagnosis for histopathologically defined perineuritis. We searched PubMed, Embase, Scopus, and Web of Science for "perineuritis." We identified 20 cases (11 M/9F) of PP: progressive, unexplained neuropathy with biopsy showing perineuritis without vasculitis or other known predisposing condition. Patients ranged in age from 18 to 75 (mean 53.7) y and had symptoms 2-24 (median 4.5) mo before diagnosis. Neuropathy was usually sensory-motor (15/20), painful (18/19), multifocal (16/20), and distal-predominant (16/17) with legs more affected than arms. Truncal numbness occurred in 6/17; 10/18 had elevated cerebrospinal fluid (CSF) protein. Electromyography (EMG) and nerve conduction studies (NCS) demonstrated primarily axonal changes. Nerve biopsies showed T-cell-predominant inflammation, widening, and fibrosis of perineurium; infiltrates in epineurium in 10/20 and endoneurium in 7/20; and non-uniform axonal degeneration. Six had epithelioid cells. 19/20 received corticosteroids, 8 with additional immunomodulators; 18/19 improved. Two patients did not respond to intravenous immunoglobulin (IVIg). At final follow-up, 13/16 patients had mild and 2/16 moderate disability; 1/16 died. Secondary causes of perineuritis include leprosy, vasculitis, neurosarcoidosis, neuroborreliosis, neurolymphomatosis, toxic oil syndrome, eosinophilia-myalgia syndrome, and rarer conditions. PP appears to be an immune-mediated, corticosteroid-responsive disorder. It mimics nonsystemic vasculitic neuropathy. Cases with epithelioid cells might represent peripheral nervous system (PNS)-restricted forms of sarcoidosis.

A severe case of neuroleukemiosis caused by B cell chronic lymphocytic leukemia, presenting as mononeuritis multiplex.

AIMS: To report an exceptional case of nerve infiltration by an otherwise benign chronic B cell leukemia, inducing severe mononeuritis multiplex. METHODS: The patient underwent extensive evaluation, including nerve conduction study and myography, brain and plexus MRI, and nerve biopsy. RESULTS: The clinical and electrophysiological diagnosis was a mononeuritis multiplex with severe motor and sensory involvement; only the nerve biopsy allowed definite diagnosis and introduction of chemotherapy, leading to resolution of sensory deficit and progressive motor improvement. DISCUSSION: Neuroleukemiosis caused by chronic lymphoid leukemia is an exceptional diagnosis. The presence of other possible causes like cryoglobulinemia could induce avoidance of nerve biopsy thus undertreating patient, since steroid treatment is not expected to be efficient on lymphocytic proliferation. Our case stretches the importance of nerve biopsy and raises neuromuscular specialist's awareness of this rare entity.

Neurolymphomatosis: involvement of peripheral nervous system revealing hematologic malignancy, a report of nine cases.

BACKGROUND AND AIM: Neurolymphomatosis is defined as an infiltration of the peripheral nervous system (PNS) by malignant lymphoma cells. It is a rare entity and diagnosis is complicated especially when PNS involvement is the initial and leading symptom. To improve knowledge of the disorder and shorten the time to diagnosis, we report a series of nine patients without a history of hematologic malignancy, who were diagnosed with neurolymphomatosis after evaluation and workup of peripheral neuropathy. METHODS: The patients were included from the Department of Clinical Neurophysiology at Pitié Salpêtrière and Nancy Hospitals over a period of 15 years. Diagnosis of neurolymphomatosis was confirmed by histopathologic examination for each patient. We characterized their clinical, electrophysiological, biological, imaging, and histopathologic features. RESULTS: The neuropathy was characterized by pain (78%), proximal involvement (44%) or of all four limbs (67%), asymmetrical or with multifocal distribution (78%), abundant fibrillation (78%), a tendency to worsen rapidly, and significant associated weight loss (67%). Neurolymphomatosis was diagnosed principally on nerve biopsy (89%) identifying infiltration of lymphoid cells, atypical cells (78%), a monoclonal population (78%), and supported by fluorodeoxyglucose-positron emission tomography, spine or plexus MRI, cerebrospinal fluid analysis, and blood lymphocyte immunophenotyping. Six patients had systemic disease and three impairment limited to the PNS. In the latter case, progression could be unpredictable and may be diffuse and explosive, sometimes occurring years after a seemingly indolent course. INTERPRETATION: This study provides better knowledge and understanding of neurolymphomatosis when neuropathy is the initial presentation.

Primary neurolymphomatosis of the trigeminal nerve.

We report a case of a primary malignant lymphoma of the trigeminal nerve that was associated with facial pain. A 65-year-old man was examined at another hospital for unilateral facial pain. Carbamazepine was prescribed, but his symptoms did not improve. Magnetic resonance imaging (MRI) revealed swelling of the trigeminal nerve and a mass lesion in Meckel's cave. The patient was referred to our hospital at this point. Gadolinium-enhanced MRI and F18-Fluorodeoxyglucose-position emission tomography suggested a likely malignant tumour and a biopsy was performed. Histopathological examination showed diffuse a large B cell lymphoma. The patient was treated with high-dose methotrexate (HD-MTX) and radiotherapy. Despite responding well to initial treatment, the patient relapsed, with lymphoma observed throughout the body. He died of pneumonia 18 months after the initial diagnosis. Facial pain is a symptom that is commonly managed in general practice. If symptoms do not improve, repeated imaging studies, including contrast MRI, is warranted. This is the first reported case of primary neurolymphomatosis (NL) of the trigeminal nerve associated with facial pain alone. Furthermore, HD-MTX and radiotherapy may be considered for the management of primary NL of a cranial nerve.

Primary Extranodal NK/T-Cell Lymphoma Presenting as Neurolymphomatosis Involving Multiple Cranial Nerves: A Case Report.

Neurolymphomatosis (NL) is a rare condition caused by the lymphomatous or leukemic infiltration of nerves and manifests as neuropathy. Most often, NL is associated with B-lineage non-Hodgkin lymphoma (NHL) and only infrequently occurs in conjunction with T- or NK-lineage NHL. Extranodal NK/T-cell lymphoma (ENKTL)-associated NL is exceedingly unusual, with only 9 cases described in the English language literature, in addition to our case. Diagnosis of NL is challenging, as the entity can mimic neuropathies of more common etiologies, and an adequate biopsy may be difficult to obtain. Timely diagnosis demands a high index of suspicion, especially for patients without a history of hematologic malignancy. We expand upon a unique case of NL exclusively involving cranial nerves and cauda equina nerve roots, as the initial manifestation of ENKTL, and contextualize our findings within the framework of previously reported NK/T-lineage NL cases.

Neoplastic nerve lesions.

Though metastasis and malignant infiltration of the peripheral nervous system is relatively rare, physicians should have a familiarity with their presentations to allow for prompt diagnosis and initiation of treatment. This article will review the clinical presentations, diagnostic evaluation, and treatment of neoplastic involvement of the cranial nerves, nerve roots, peripheral nerves, and muscle. Due to the proximity of the neural structure traversing the skull base, metastasis to this region results in distinctive syndromes, most often associated with breast, lung, and prostate cancer. Metastatic involvement of the nerve roots is uncommon, apart from leptomeningeal carcinomatosis and bony metastasis with resultant nerve root damage, and is characterized by significant pain, weakness, and numbness of an extremity. Neoplasms may metastasize or infiltrate the brachial and lumbosacral plexuses resulting in progressive and painful sensory and motor deficits. Differentiating neoplastic involvement from radiation-induced injury is of paramount importance as it dictates treatment and prognosis. Neurolymphomatosis, due to malignant lymphocytic infiltration of the cranial nerves, nerve roots, plexuses, and peripheral nerves, deserves special attention given its myriad presentations, often mimicking acquired demyelinating neuropathies.

Neurolymphomatosis in follicular lymphoma: an autopsy case report.

Neurolymphomatosis is a neurological manifestation of lymphoma that involves the cranial or spinal peripheral nerves, nerve roots, and plexus with direct invasion of neoplastic cells. Neurolymphomatosis is rare among patients with low-grade lymphoma. We report an autopsied case of neurolymphomatosis that arose from follicular lymphoma. A 49-year-old woman who presented with pain of her neck and shoulder and numbness of her chin. Computed tomography revealed enlarged lymph nodes in her whole body, and biopsy from the axillary lymph node revealed grade 2 follicular lymphoma. Although the patient underwent chemotherapy, she gradually developed muscle weakness in the upper limbs and sensory disturbances of the trunk and limbs. 18 F-fluorodeoxyglucose positron emission tomography (FDG-PET) revealed increased tracer uptake of the cervical nerve roots. Repeated FDG-PET after additional therapy revealed progression of disease within the nerve roots and brachial plexus, whereas gadolinium-contrast magnetic resonance imaging (MRI) showed weak enhancement of the cervical nerve roots without formation of mass lesions. She died after a total disease duration of 12 months. Postmortem observations revealed invasion of lymphoma cells into the cervical nerve roots, dorsal root ganglia, and subarachnoid spaces of the spinal cord. Neurolymphomatosis was prominent at the segments of C6-Th2. Combined loss of axons and myelin sheaths was observed in the cervical nerve roots and posterior columns. Lymphoma cells also invaded the cranial nerves. The subarachnoid and perivascular spaces of the brain demonstrated focal invasion of the lymphoma. Mass lesions were not observed in the central nervous system. The lymphoma cells did not show histological transformation to higher grades, and the density of the centroblasts remained at grade 2. Our report clarifies that low-grade follicular lymphoma can manifest as neurolymphomatosis and central nervous system invasion in the absence of transformation toward higher histological grades. FDG-PET may be more sensitive to non-mass-forming lesions, including neurolymphomatosis, than gadolinium-contrast MRI.

Particularities of Neurological Manifestations in Adult T-Cell Leukemia/Lymphoma: Need for a Multidisciplinary Approach-A Narrative Review.

ATL is a rare but a highly aggressive T-cell neoplasm associated with human T-cell leukemia virus-1 (HTLV-1) infection. Human T-cell lymphotropic virus type-1 (HTLV-1) is a oncogenic retrovirus responsible for the development of adult T-cell leukemia (ATL), but also for other non-malignant diseases, such as HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). HTLV-1 has a higher prevalence in Japan, the Caribbean, South America, intertropical Africa, Romania, and northern Iran. ATL patients can have an extensive spectrum of neurological manifestations. Numerous factors can be implicated, such as central nervous system infiltrates, neurolymphomatosis, complications to medication or allogeneic stem cell transplantation, HAM/TSP, infections, metabolic disturbances. The neurological complications are not always easy to recognize and treat. Thus, this review underlines the necessity of a multidisciplinary approach in ATL patients with neurological symptomatology.

A case report of secondary neurolymphomatosis showing selective nerve infiltration and massive lumbar plexus enlargement.

BACKGROUND: Neurolymphomatosis (NL) is a rare manifestation of malignant lymphoma that shows selective infiltration to the peripheral nervous system primarily or secondarily. We report a patient with secondary NL caused by germinal center B-cell (GCB)-type diffuse large B-cell lymphoma (DLBCL) who showed selective infiltration of the lumbar plexus to the spinal cord and massive nerve enlargement resulting in severe pain. CASE PRESENTATION: A 72-year-old female exhibited asymmetric motor and sensory impairments and pain in the lower limbs that progressed for five months. Magnetic resonance imaging (MRI) showed an enlarged lumbar plexus, which continued to the cauda equina via the L3 and L4 spinal nerves. Her symptoms gradually worsened. Ten months after the onset of symptoms, the enlarged cauda equina filled the spinal canal space, and the spinal cord was swollen. A cauda equina biopsy was performed, and she was diagnosed with GCB-type DLBCL with CD10 positivity. The primary tumor was found in a mammary cyst. The autopsy study did not show apparent infiltration, except in the nervous system. CONCLUSIONS: Although there are many neurologic phenotypes of malignant lymphoma, the association between the cytological characteristics of lymphoma and the neurological phenotypes is still unclear. Several reports of CD10-positive secondary NL are available, whereas peripheral or central nervous tissue origin lymphoma cases are mostly negative for CD10. CD10 staining may be useful for distinguishing primary NL from secondary NL. NL often has a strong organotropism for peripheral nervous tissue, which makes early diagnosis challenging.

CIDP mimics: a case series.

BACKGROUND: To report our experience with a group of patients referred for refractory CIDP who fulfilled "definite" electrodiagnostic EFNS criteria for CIDP but were found to have an alternate diagnosis. METHODS: Patients who were seen between 2017 and 2019 for refractory CIDP that fulfilled "definite" electrodiagnostic ENFS criteria for CIDP, but had an alternate diagnosis, were included. Patients who correctly had CIDP, anti MAG neuropathy, or MMN with conduction block, were excluded from the study. Demographics, clinical and electrophysiological characteristics, pertinent workup, final alternate diagnoses, and outcomes were collected. RESULTS: Seven patients were included: POEMS (n = 5), CANOMAD (n = 1), and neurolymphomatosis (n = 1). Most patients reported neuropathic pain and leg swelling (n = 6) or significant weight loss (n = 4). All patients had a monoclonal protein, and most patients who were tested had an elevated VEGF and CSF cyto-albuminologic dissociation. Electrophysiology showed pronounced intermediate more than distal demyelination, and axonal loss in the lower extremities. Response to steroids or IVIG varied, but some patients did respond to these treatments, especially early in the disease. CONCLUSION: Pain, systemic symptoms, suggestive electrophysiological findings, and/or a serum monoclonal protein should raise suspicion for CIDP mimics. Initial response to steroids or IVIG, over reliance on CSF, and electrophysiology findings can all be misleading.

Isolated primary neurolymphomatosis with cranial multineuritis: a case presentation.

BACKGROUND: Isolated primary neurolymphomatosis (NL) of cranial multineuritis is a very rare condition that refers to the lymphomatous invasion of cranial nerves only. There are sparse cases of isolated cranial nerves NL reported worldwide. CASE PRESENTATION: We present magnetic resonance imaging (MRI) and cerebrospinal fluid (CSF) findings of a 63-year-old female patient suffering from isolated neurolymphomatosis of cranial multineuritis with a wide constellation of syndromes including binocular diplopia, left facial paralysis and pain, syncope episodes, and progressive dysphagia. A contrasted MRI brain showed multiple cranial nerves enhancement. Extensive workup for infectious, autoimmune, neoplastic, paraneoplastic, or inflammatory etiologies had been unrevealing except CSF cytology revealed large atypical monotypic B cells that were suspicious for non-Hodgkin lymphoma on the third large volume tap. The decision of biopsy was deferred after the risks and benefits discussion. Following the four cycles of empiric methotrexate-based induction chemotherapy, the patient's symptoms resolved, and a complete radiographic response was achieved without whole-brain radiation or autologous hematopoietic cell transplantation. In the latest follow-up, she is independent with her daily activities and remains in clinical and radiographic remission more than 3 years since initial chemotherapy. CONCLUSION: Isolated NL of cranial nerves can present diagnostic and management pitfalls for the neurologist, neurosurgeons, and oncologists. Since current diagnostic modalities have modest sensitivity and a pathological diagnosis is often difficult, empiric treatment once other possibilities are ruled out can carry a good prognosis.

Neurological misdiagnoses of lymphoma.

BACKGROUND: Lymphoma of the nervous system is rare and usually involves the brain, spinal cord, or peripheral nerves. Hence, it has varied clinical presentations, and correct diagnosis is often challenging. Incorrect diagnosis delays the appropriate treatment and affects prognosis. We report 5 patients with delayed diagnosis of lymphoma involving the central and/or peripheral nervous system, initially evaluated for other neurological diagnoses. We also discuss the challenge of diagnosis and appropriate testing. METHODS: Retrospective review of 2011-2019 records of patients with confirmed nervous system lymphoma diagnosed in a tertiary care medical center. RESULTS: We present 5 adult patients initially evaluated for inflammatory myelopathy, inflammatory lumbosacral plexopathy, atypical parkinsonism, and demyelinating disease of the CNS. Final diagnosis of the nervous system lymphoma was delayed by 4 to 18 months and was based on tissue biopsy in 4, and on CSF and bone marrow examination in 1 patient. CONCLUSIONS: Lymphoma may imitate various central and peripheral nervous system disorders. We suggest several red flags that indicate the need to consider lymphoma, including subacute but progressive symptomatic evolution, painful neurological deficit, unclear clinical diagnosis, and transient steroid responsiveness. Correct diagnosis often requires a combination of diagnostic tests, while pathology testing is crucial for early diagnosis and is strongly recommended in the appropriate clinical setting.

Intravascular large B-cell lymphoma affecting multiple cranial nerves: A histopathological study.

Intravascular large B-cell lymphoma (IVLBCL) is a rare form of lymphomas with poor prognosis, characterized by atypical lymphocytes selectively growing within the lumen of small or medium-sized vessels. Here, we report a case of intracerebral IVLBCL in a 54-year-old man who died three months after symptom onset. The diagnosis was made by postmortem pathological examination, based on the identification of multiple ischemic lesions, with small or medium-sized vessels filled with malignant B-cells, in the cerebral hemispheres, cerebellum, midbrain, and medulla oblongata, including the external cuneate nucleus and trigeminal spinal tract nucleus. Apart from necrotic lesions, specific histopathological search for occluded vessels in the other brain stem structures permitted identification of significant involvement of the cuneate nucleus, solitary tract nucleus, hypoglossal nucleus, and inferior olivary complex. Small vessels affected by IVLBCL were also found in the trunks of the oculomotor, trigeminal, glossopharyngeal, vagal, and hypoglossal nerves. These histopathological findings were consistent with some cranial nerve symptoms/signs ascertained during hospitalization, such as diplopia, dysphonia, and asymmetry/hypomotility of the palatal veil. The case study presented here reports novel insights on radiological, anatomical, and clinical correlations of the IVLBCL, including the possible involvement of nuclei and trunks of multiple cranial nerves. The reported findings may help clinicians in the early identification of this rapidly progressive disease that can be easily misdiagnosed, through integrated neuroradiological, neurological and neuropathological approaches.

Fried egg sign: A typical ultrasonography feature of neurolymphomatosis.

Neurolymphomatosis (NL) is a rare condition caused by non-Hodgkin's lymphoma or leukemia. We present a case of NL and describe ultrasound features, including the "fried egg sign" in which there is a clear demarcation between an avascular echogenic core and a hypoechoic vascularized peripheral zone that may help to distinguish NL from primary nerve sheath tumors.

Neurolymphomatosis, a rare manifestation of peripheral nerve involvement in lymphomas: Suggestive features and diagnostic challenges.

Neurolymphomatosis, the infiltration of the peripheral nervous system from lymphoid cells, represents an uncommon manifestation of lymphomas. We describe the challenging diagnostic work-up in a patient with neurolymphomatosis. A 58-year-old woman with previous breast diffuse large B-cell lymphoma treated with chemo- and radiation-therapy, presented with dysesthesias, neuropathic pain at left abdomen and thigh, and weakness at left lower limb 9 years after disease remission. Neurophysiology revealed left T10-L4 radiculo-plexopathy with no abnormalities at cerebrospinal fluid (CSF), nerve ultrasound, and 18 fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT). MR-neurography disclosed left rectus abdominis muscle atrophy, neurogenic edema, and denervation. Radiation-induced damage, paraneoplastic, infectious radiculo-plexopathies, and atypical chronic inflammatory demyelinating polyradiculoneuropathy were ruled out. Neurolymphomatosis was suspected, and the patient treated with rituximab with improvement. Despite treatment, the radiculo-plexopathy eventually extended to the right side and sacral roots. Later in the disease course, sural nerve biopsy confirmed the diagnosis. Maintenance therapy was continued, until cutaneous localizations occurred, requiring salvage therapy and autologous stem cell transplant. Although rare, neurolymphomatosis should be considered in all patients with lymphomas and unexplained peripheral nervous system involvement. Hematological, CSF, and neuroimaging findings may be unremarkable, and a high index of suspicion required in order to achieve the diagnosis.