Outcomes of radiocarpal pinning to facilitate nerve repair in wrist-level ulnar nerve injuries with defect.

BACKGROUND: The ideal scenario for ulnar nerve repair is primary end-to-end neurorrhaphy in a tension-free environment. However, this could be complicated by soft tissue loss, scarring, and neuroma formation in a delayed injury, creating a nerve defect. With a wrist-level nerve defect, a flexion position can help shorten the nerve gap; however, maintaining the position can be challenging intraoperatively and postoperatively. METHODS: Previously, we proposed our method of using a 1.6-mm K wire for radius-lunate-capitate pinning of the wrist in flexion to minimize the nerve gap, thereby facilitating neuroma excision and end-to-end neurorrhaphy in delayed ulnar nerve injury. In this study, we elaborate our method and present our case series. RESULTS: From October 2018 to July 2020, five patients (mean age: 48.2 years; mean delay from injury to surgery: 84.6 days; mean follow-up: 17.5 months) were retrospectively reviewed. The mean flexion fixation angle was 52°, and the K wire was removed at an average of 5.1 weeks postoperatively. All patients were followed up for a minimum of 12 months. All patients achieved M4 and S3 or S3+ neurologically (according to the criteria of the Nerve Injuries Committee of the British Medical Research Council). The mean disabilities arm, shoulder, and hand score was 14.1. The mean grasp and pinch strengths were, respectively, 76.8% and 63.6% of the contralateral hand. All wrist range of motion returned to normal within 12 weeks. No complications were noted intraoperatively or postoperatively. CONCLUSION: Our study showed that radiocarpal pinning of the wrist in flexion was safe and convenient to minimize the nerve gap and to facilitate end-to-end neurorrhaphy in limited-sized wrist-level ulnar nerve defects.

Alpha-2 macroglobulin for the treatment of neuroma pain in the stump of a below-knee amputee patient.

This case report describes the successful treatment of neuroma pain in the setting of below knee amputations using alpha-2-macroglobulin (A2M). A 34-year-old female patient presented with 9 months of stump pain despite conservative treatment. The exam revealed persistent pain through rest periods and weight-bearing status during therapy. Ultrasound showed neuroma formation with neovascularization. The patient underwent two A2M hydrodissection treatments, 2 weeks apart. The patient reported significant pain relief. Ultrasound showed decreases in neovascularization and cross-sectional area of the neuroma. The patient was able to ambulate pain-free for 2 years and reported no pain since. A2M may be a treatment for patients with neuroma pain in the setting of amputations.

Targeted muscle reinnervation and regenerative peripheral nerve interfaces for pain prophylaxis and treatment: A systematic review.

OBJECTIVE: Nerve pain frequently develops following amputations and peripheral nerve injuries. Two innovative surgical techniques, targeted muscle reinnervation (TMR) and regenerative peripheral nerve interfaces (RPNI), are rapidly gaining popularity as alternatives to traditional nerve management, but their effectiveness is unclear. LITERATURE SURVEY: A review of literature pertaining to TMR and RPNI pain results was conducted. PubMed and MEDLINE electronic databases were queried. METHODOLOGY: Studies were included if pain outcomes were assessed after TMR or RPNI in the upper or lower extremity, both for prophylaxis performed at the time of amputation and for treatment of postamputation pain. Data were extracted for evaluation. SYNTHESIS: Seventeen studies were included, with 14 evaluating TMR (366 patients) and three evaluating RPNI (75 patients). Of these, one study was a randomized controlled trial. Nine studies had a mean follow-up time of at least 1 year (range 4-27.6 months). For pain treatment, TMR and RPNI improved neuroma pain in 75%-100% of patients and phantom limb pain in 45%-80% of patients, averaging a 2.4-6.2-point reduction in pain scores on the numeric rating scale postoperatively. When TMR or RPNI was performed prophylactically, many patients reported no neuroma pain (48%-100%) or phantom limb pain (45%-87%) at time of follow-up. Six TMR studies reported Patient-Reported Outcomes Measurement Information System (PROMIS) scores assessing pain intensity, behavior, and interference, which consistently showed a benefit for all measures. Complication rates ranged from 13% to 31%, most frequently delayed wound healing. CONCLUSIONS: Both TMR and RPNI may be beneficial for preventing and treating pain originating from peripheral nerve dysfunction compared to traditional techniques. Randomized trials with longer term follow-up are needed to directly compare the effectiveness of TMR and RPNI with traditional nerve management techniques.

Left Gluteal Maximus Neuroma Causing Long-Standing Gluteal Pain.

ABSTRACT: Diagnosing buttock pain is a challenge due to complex anatomy and multiple causes. Potential pathologies range from common and benign to rare and life-threatening. Common causes for buttock pain include referred pain from the lumbar spine and sacroiliac joint, hamstring origin tendinopathy, myofascial pain, ischiogluteal bursitis, gluteal pathology, and piriformis syndrome. Rarer causes include malignancy, bone infection, vascular anomalies, and spondyloarthropathies. Other conditions may be present concurrently in the lumbar and gluteal area, which can cloud the clinical picture. Correct diagnosis and early treatment may improve quality of life by providing a targetable reason for their distress, improving pain, and allowing the patient to get back to their activities of daily living. When treating a patient with buttock pain, it is essential to reevaluate the diagnosis when symptoms fail to improve despite appropriate intervention.Here, we discuss a case of a peripheral nerve sheath tumor found in the left gluteus medius muscle of a patient that caused persistent, debilitating buttock pain. After years of treatment for piriformis syndrome and possible spinous causes, the patient was ultimately diagnosed with a peripheral nerve sheath tumor through magnetic resonance imaging with contrast. Peripheral nerve sheath tumors are a diverse group of mostly benign tumors that can occur sporadically or associated with certain disease processes. These tumors usually present with pain, a soft tissue mass, or focal neurological deficits. Upon removal of the tumor, her gluteal pain completely resolved.

Mechanosensitive Ion Channel TMEM63A Gangs Up with Local Macrophages to Modulate Chronic Post-amputation Pain.

Post-amputation pain causes great suffering to amputees, but still no effective drugs are available due to its elusive mechanisms. Our previous clinical studies found that surgical removal or radiofrequency treatment of the neuroma at the axotomized nerve stump effectively relieves the phantom pain afflicting patients after amputation. This indicated an essential role of the residual nerve stump in the formation of chronic post-amputation pain (CPAP). However, the molecular mechanism by which the residual nerve stump or neuroma is involved and regulates CPAP is still a mystery. In this study, we found that nociceptors expressed the mechanosensitive ion channel TMEM63A and macrophages infiltrated into the dorsal root ganglion (DRG) neurons worked synergistically to promote CPAP. Histology and qRT-PCR showed that TMEM63A was mainly expressed in mechanical pain-producing non-peptidergic nociceptors in the DRG, and the expression of TMEM63A increased significantly both in the neuroma from amputated patients and the DRG in a mouse model of tibial nerve transfer (TNT). Behavioral tests showed that the mechanical, heat, and cold sensitivity were not affected in the Tmem63a-/- mice in the naïve state, suggesting the basal pain was not affected. In the inflammatory and post-amputation state, the mechanical allodynia but not the heat hyperalgesia or cold allodynia was significantly decreased in Tmem63a-/- mice. Further study showed that there was severe neuronal injury and macrophage infiltration in the DRG, tibial nerve, residual stump, and the neuroma-like structure of the TNT mouse model, Consistent with this, expression of the pro-inflammatory cytokines TNF-α, IL-6, and IL-1ß all increased dramatically in the DRG. Interestingly, the deletion of Tmem63a significantly reduced the macrophage infiltration in the DRG but not in the tibial nerve stump. Furthermore, the ablation of macrophages significantly reduced both the expression of Tmem63a and the mechanical allodynia in the TNT mouse model, indicating an interaction between nociceptors and macrophages, and that these two factors gang up together to regulate the formation of CPAP. This provides a new insight into the mechanisms underlying CPAP and potential drug targets its treatment.

[Involuntary movements of the stump after transtibial amputation: Jumping stump syndrome]. / Movimientos involuntarios del muñón tras una amputación transtibial: síndrome del muñón saltarín.

45-year-old woman with history of hallux valgus surgery and torpid evolution, which led to transtibial amputation. Six months after surgery, she began to experience involuntary movements of the stump such as myoclonus, that were triggered by touch or hip extension, associating worsening of the previous stump and phantom limb pain. During the following year, concurring with change of prosthesis, symptoms progressively worsened, which limited walking. The therapeutic approach to pain and myoclonus was initially pharmacological, without response. Given the clinical and ultrasound suspicion of neuroma in the external popliteal sciatic nerve, it was infiltrated with corticosteroid and anesthetic, and the gastrocnemius with botulinum toxin type A, without success. Finally, the myoclonus disappeared, and the pain decreased after surgical remodeling of the stump and resection of the neuroma. This clinical picture is known as jumping stump syndrome and is a rare complication that must be considered after amputation.

Multiple Cutaneous Solitary Circumscribed Neuroma in a Patient with Neurofibromatosis Type 2: An "Incidentaloma" or New Association?

Solitary circumscribed neuroma formerly known as palisaded encapsulated neuroma is a rare, benign neural tumor that usually presents as a painless firm nodule or papule on the face and within oral cavity, although they can occur elsewhere on the body. No association with neurofibromatosis has been reported in the literature. Herein, we report, a previously unreported unique association of neurofibromatosis type 2 (NF-2) with multiple cutaneous solitary circumscribed neuromas in a 24-year-old female. A 24-year-old female with history of NF-2 presented with two slow-growing soft-to-firm papules on the chin and forehead that had been gradually increasing in size over a period of 5 years. The papule on the chin was increasingly tender to palpation. Histologic sections demonstrated a dermal based almost encapsulated, smoothly contoured tumefactive mass composed of spindle cell proliferation with neuroid structures and foci of palisaded growth (resembling schwannoma) and intralesional cleft like spaces. By immunohistochemistry, the lesional cells were strongly and diffusely positive for S-100 and SOX10 with multifocal neurofilament expression while the "capsule" was diffusely reactive for epithelial membrane antigen. The overall features were considered prototypic for solitary circumscribed neuroma. The patient is 18-months post-surgical resection with no evidence of recurrence. In summary, we report for the first time a case of multiple solitary circumscribed neuromas in a patient with known NF2. We highlight pertinent diagnostic clues relevant to surgical pathologist to facilitate recognition (as this tumor is often mistaken for schwannoma or neurofibroma). The clinical behavior is excellent and surgical resection is considered curative.

Targeted muscle reinnervation: a brief history of a promising procedure for effective management of amputation pain.

Each year, 27.5% of the 150 000 people in the United States who require lower extremity amputation experience significant postoperative complications, including pain, infection, and need for reoperation. Postamputation pain, including RLP and PLP, is debilitating. While the causes of such pain remain unknown, neuroma formation following sensory nerve transection is believed to be a major contributor. Various techniques exist for management of a symptomatic neuroma, but few data exist on which technique is superior. Furthermore, there are few data on primary prevention of neuroma formation following injury or intentional transection. The TMR technique shows promise for both management of PLP and RLP and prevention of neuroma formation. Following amputation, transected sensory nerves are coapted to nearby motor nerve supplying remaining extremity musculature. Not only does this procedure generate increased myoelectric signals for improved prosthesis control, TMR appears to neurophysiologically alter sensory nerves, preventing formation of painful sensory neuromas. The sole RCT to date evaluating the efficacy of TMR showed statistically significant reduction in PLP. TMR is not limited to use in the setting of major limb amputation. It has also been used in the setting of post-mastectomy pain, abdominal wall neuromas, digital amputations, and headache surgeries. This article reviews the origin of TMR and provides a brief description of histologic changes following the procedure, as well as current data regarding the efficacy of TMR with regard to postoperative pain relief. It also seeks to provide a concise, comprehensive resource for providers to facilitate better discussions with patients about treatment options.

Musical therapy attenuates neuroma pain by modifying leptin expression.

BACKGROUND: Accumulating evidence reveals that music therapy appears to help patients with pain. However, there is a limited understanding of the underlying mechanisms. Several studies indicate that leptin level has a crucial relationship with acute and chronic pain. Herein, we evaluated the effects of music stimulation and the potential roles of adipokines (leptin) in pain behaviors. METHODS: We used a tibial neuroma transposition (TNT) rat model to mimic neuroma pain. Adult male Sprague-Dawley rats were randomly assigned to one of the three groups (n = 6):group 1 (GC), TNT with white noise; group 2(GM), TNT with music; and group 3(GH), TNT. White noise and music stimulation was given once a day following surgery until the end of the study (42nd day). Pain behavioral tests were carried out before surgery and on the 3rd, 10th, 14th, 21st, 28th, 35th, and 42nd days after surgery. At the end of the observation period, we analyzed the histological samples of blood, spinal cord, and prefrontal cortex to investigate the role of leptin in pain behaviors modulated by white noise and sound stimulation. RESULT: Music therapy might improve the pain of TNT rats. Music stimulation ameliorated paw withdrawal thermal latency (PWTL) from the 3rd day after the surgery while the mechanical pain was improved 21 days after the operation.Music stimulation also increased leptin expression in the spinal cord, prefrontal cortex.White noise had no obvious effect. CONCLUSION: Music therapy might improve the pain of TNT rats. Besides, music stimulation ameliorated TNT-induced pain behaviors and affected leptin expression.

A retrospective case series of prophylactic neurectomy during total knee arthroplasty.

INTRODUCTION: Total knee arthroplasty is a common operation performed to relieve pain and restore functional activity. While overall widely successful, a subset of patients has continued pain postoperatively with no identifiable cause. Neuroma formation has been identified as a possible contributor to this unexplained pain, often necessitating an additional procedure for neuroma removal. The purpose of our study was to evaluate if prophylactic neurectomy could reduce the occurrence of postoperative pain. METHODS: A total of 112 patients were compared, 44 control patients and 68 neurectomy patients. Demographic information, Numerical rating pain scale (NRS) and Knee Society Scores (KSS) were collected pre- and post-operatively. Patients were additional asked if they were overall satisfied with the operation. RESULTS: There were no differences between groups with respect to age (Median: 71 vs 69 years, p = 0.28), male sex (41% vs 44%, p = 0.85), or body mass index (Median: 32.2 vs 31.3, p = 0.80). When comparing the degree of change following surgery there were no statistically significant differences observed in NRS pain scores (Median change: -7 vs -6, p = 0.89) or KSS scores (Median change: +44 vs +40, p = 0.14). Similarly, there was no statistically significant difference in overall patient-reported satisfaction with the knee replacement (82.5% vs 86.6%, p = 0.59). CONCLUSION: We did not find a statistically significant difference in NRS, KSS, or overall patient satisfaction between the prophylactic neurectomy and control patient groups. Larger studies with evaluation of the nerve diameter will be needed to determine which patients are at risk for symptomatic neuroma development following total knee arthroplasty.

In vivo confocal microscopic study of corneal innervation in Sjögren's Syndrome with or without small fiber neuropathy.

PURPOSE: To study changes in the subbasal nerve plexus by In vivo confocal microscopy (IVCM) in Sjögren's Syndrome (SS) with or without associated Small Fiber Neuropathy (SFN), in order to prevent diagnostic delay. METHODS: Seventy-one patients with SS, including 19 with associated SFN, 20 healthy volunteers and 20 patients with Meibomian gland dysfunction (MGD) were included in this retrospective case-control study. IVCM was used to investigate subbasal nerve plexus density and morphology. RESULTS: Corneal sensitivity as evaluated with the Cochet-Bonnet aesthesiometer was significantly reduced in the SS group versus the control group (P = 0.026) and the MGD group (P = 0.037). The number of inflammatory cells was significantly increased in the SS group to 86.2 ± 82.1 cells/mm2 compared to the control group (P < 0.001). The density of the subbasal nerve plexus was significantly reduced to 16.7 ± 6.5 mm/mm2 in the SS group compared to the control group (P < 0.005) and the MGD group (P = 0.042). The tortuosity of the nerves in the SS group was significantly increased compared to the control group (P < 0.001) and the MGD group (P = 0.025). The average number of subbasal nerve plexus neuromas was significantly increased in the SS group compared to the control group (P = 0.001), with a significant increase in the average number of neuromas in SS patients with associated SFN compared to SS patients without SFN (P = 0.008). CONCLUSION: IVCM can be useful to detect corneal nerve changes in SS patients and may allow earlier diagnosis of the disease and to consider new therapeutic approaches.

Feasibility of Magnetic Resonance-Guided High-Intensity-Focused Ultrasound (MRgHIFU) Ablation of Stump Neuromas for the Relief of Chronic Postamputation Neuropathic Pain.

Up to 70% of limb amputees develop chronic postamputation neuropathic pain (CPANP) which includes phantom pain and residual limb neuropathic pain due to neuroma formation. CPANP often requires invasive procedures aimed at neuroma ablation. Five amputees received 6 noninvasive magnetic resonance-guided high-intensity-focused ultrasound MRgHIFU treatments ExAblate®, Insightec, Tirat-Carmel, Israel). Although ablative temperature (>65°C) at the neuroma was reached in only 1 patient, pain intensity dropped from 5.7 at baseline to 4.3 and back to 5.6 at 3 and 6 month follow-up. Post-treatment bone necrosis was demonstrated in 1 patient. Although no firm conclusion about the effectiveness of MRgHIFU for CPANP could be drawn, further studies are warranted.

Superficial peroneal nerve neuroma after syndesmotic stabilisation surgery.

The ankle is a region crowded with multiple neurovascular and musculotendinous structures. We describe a case of a rare neurological complication following ankle surgery.

Long-Term Outcomes after Surgical Treatment of Radial Sensory Nerve Neuromas: Patient-Reported Outcomes and Rate of Secondary Surgery.

BACKGROUND: This study aimed to (1) describe long-term patient-reported outcomes of surgically treated symptomatic radial sensory nerve neuromas on function, pain interference, pain intensity, and satisfaction; (2) assess which factors were associated with worse function, higher pain intensity, and more pain interference; and (3) describe the secondary surgery rate and factors associated with secondary surgery. METHODS: The authors conducted a retrospective review of patients surgically treated for radial sensory nerve neuroma from 2002 to 2016 (n = 54). Twenty-five of these 54 patients completed a follow-up survey including the Patient-Reported Outcomes Measurement Information System (PROMIS) upper extremity, pain interference, and depression scales; numerical rating scale pain and satisfaction instruments; and the global rating scale of change, at a mean period of 10.7 ± 4.3 years after neuroma surgery. RESULTS: The mean PROMIS scores were 45.0 ± 12.1 for upper extremity, 55.5 ± 10.3 for pain interference, and 49.9 ± 10.2 for depression, and were within 1 SD of the general population. Eight patients (32 percent) reported symptoms as unchanged or worse following neuroma surgery. The median numerical rating scale pain was 3 (interquartile range, 1 to 6) and the global rating scale of change satisfaction was 10 (interquartile range, 7 to 10). Older patients (p = 0.002) and patients with higher PROMIS pain interference (p < 0.001), higher numerical rating scale for pain (p = 0.012), and lower global rating scale of change scores (p = 0.01) had worse PROMIS upper extremity scores. The secondary surgery rate was 20 percent and was associated with the presence of multiple neuromas (p = 0.001). CONCLUSIONS: Radial sensory nerve neuromas remain difficult to treat. They have a high secondary surgery rate (20 percent), with only 68 percent of patients reporting improvement after surgical intervention. Patient-reported outcomes after surgery are similar to conditions of the general population; however, the range of outcomes is wide.

Neurocap Use for the Treatment of Iatrogenic Neuropathic Pain: Preliminary Operative Results in 3 Patients.

Painful neuromas are a devastating condition that is notoriously difficult to treat. The large number of techniques that have been attempted suggest that no one technique is superior. Neuromas often occur in the extremities, but iatrogenically caused pain in the head and neck area has also been described. This article describes 3 consecutive patients diagnosed with traumatic neuroma who underwent transection of the causative nerve, followed by capping of the nerve stump with a Neurocap. With a follow-up of 7 to 24 months, our results show a marked reduction in the pain scores of all 3 patients. The preliminary results indicate that this technique might be a viable treatment option for patients with a suspected neuroma in the head and neck area.

Neuroma.

Neuroma formation occurs because of some degree of nerve injury followed by improper intrinsic nerve repair. The cause of neuroma pain is incompletely understood, but appears to be multifactorial in nature, including local and system changes. A comprehensive understanding of nerve anatomy, injury, and repair techniques should be used when dealing with neuroma formation and its physical manifestations. Diagnosis of neuroma is clinically characterized by pain associated with scar, altered sensation within the given nerve distribution, and a Tinel sign. The pathophysiology of neuroma formation is reviewed.

Regenerative Peripheral Nerve Interfaces for Prevention and Management of Neuromas.

Symptomatic neuromas are a common cause of postamputation pain that can lead to significant disability. Regenerative peripheral nerve interface surgery is performed to treat symptomatic neuromas and prevent the development of neuromas. This review delineates the clinical problem of postamputation pain, describes the limitations of the available treatment methods, and highlights the need for an effective treatment strategy that leverages the biologic processes of nerve regeneration and muscle reinnervation. The evidence supporting use of regenerative peripheral nerve interface surgery to mitigate neuroma formation is discussed and the rationale behind the efficacy of regenerative peripheral nerve interfaces is explored.

Patient-Reported Outcomes following Surgical Treatment of Symptomatic Digital Neuromas.

BACKGROUND: Many surgical techniques are used to treat symptomatic neuroma, but options are limited for digital neuromas because of a paucity of soft-tissue coverage and/or the absence of the terminal nerve end. The authors assessed factors that influence patient-reported outcomes after surgery for symptomatic digital neuroma. METHODS: The authors retrospectively identified 29 patients with 33 symptomatic digital neuromas that were treated surgically. Patients completed the Patient-Reported Outcomes Measurement Information System (PROMIS) Upper Extremity and Pain Interference scales, a numeric rating scale for pain, and the PROMIS Depression scale at a median follow-up of 7.6 years postoperatively (range, 3.2 to 16.8 years). Surgical treatment for neuroma included excision with nerve repair/reconstruction (n =13; 39 percent), neuroma excision alone (n =10; 30 percent), and excision and implantation (n =10; 30 percent). Multivariable linear regression was performed to identify the factors that independently influenced patient-reported outcomes. RESULTS: The mean postoperative PROMIS Upper Extremity score was 45.2 ± 11.2, the mean Pain Interference score was 54.3 ± 10.7, and the mean numeric rating scale pain score was 3 (interquartile range, 1 to 5). Compared with other treatment techniques, neuroma excision with nerve repair/reconstruction was associated with lower numeric rating scale pain scores; lower Pain Interference scores, corresponding to less daily impact of pain; and higher Upper Extremity scores, reflecting better upper extremity function. Older age and higher Depression scores were associated with lower Upper Extremity scores and higher Pain Interference scores. Smoking was associated with higher Pain Interference and numeric rating scale pain scores. CONCLUSIONS: Neuroma excision followed by nerve repair/reconstruction resulted in better outcomes compared with neuroma excision alone with or without implantation. Patient age and psychosocial factors influenced patient-reported outcomes. CLINICAL QUESTION/LEVEL OF EVIDENCE: Risk, III.

Ictericia obstructiva por neuroma de amputación de vía biliar: Reporte de caso / Obstructive ictericia by neuroma of amputation of via biliar: Case report

Los neuromas del conducto biliar se desarrollan a partir de las fibras nerviosas simpáticas y parasimpáticas que envuelven la pared de la vía biliar. Mujer de 44 años de edad con antecedente de colecistectomía convencional seis meses previos al ingreso acude a emergencia por ictericia obstructiva de 15 días de evolución. En los estudios de imagen impresiona la presencia de una masa a nivel de las vías biliares considerándose el diagnostico de una neoplasia maligna. Por los antecedentes, ausencia de marcadores tumorales se decide realizar una biopsia percutánea sin resultados concluyente, realizándose posteriormente una intervención quirúrgica con estudio anatomo-patológico compatible con neuroma de amputación de vía biliar. El neuroma de amputación a nivel de la vía biliar es un tumor infrecuente. Puede manifestarse clínicamente como una ictericia obstructiva y suele simular a un tumor maligno de las vías biliares. El manejo quirúrgico es el tratamiento definitivo.

Neuromas of the bile duct develop from the sympathetic and parasympathetic nerve fibers that surround the wall of the bile duct. A 44-year-old woman with a history of conventional cholecystectomy six months prior to hospital admission attended emergency due to obstructive jaundice that lasted 15 days. In the imaging studies, the presence of a mass at the level of the bile ducts is considered, considering the diagnosis of a malignant neoplasm. Due to the antecedents, the absence of tumor markers, it was decided to perform a percutaneous biopsy without conclusive results, performing later a surgical intervention with anatomopathological study compatible with neuroma of biliary tract amputation. The amputation neuroma at the level of the bile duct is an infrequent tumor. It can manifest clinically as obstructive jaundice and usually simulates a malignant tumor of the bile ducts. Surgical management is the definitive treatment.