[Patients' perceptions of and attitudes towards epilepsy surgery: mistaken concepts in Colombia]. / Percepciones y actitudes de los pacientes frente a la cirugia de la epilepsia: conceptos equivocados en Colombia.

INTRODUCTION: Selected patients with drug-resistant focal epilepsy benefit from epilepsy surgery, however significant delays remain. The aim of this study was to assess knowledge and attitudes toward epilepsy surgery among patients with epilepsy and identify barriers that might delay the treatment. PATIENTS AND METHODS: A 10-minute questionnaire was administered to patients with epilepsy in Colombia. Survey assessed the following: knowledge of surgical options, perceptions about the risks of surgery vs. ongoing seizures, disease disability, treatment goals, and demographic and socioeconomic variables. RESULTS: We recruited 88 patients with focal epilepsy. More than half of patients (56%) were not aware that surgery might be an option. Apprehension about epilepsy surgery was evident, 60% of patients perceived epilepsy surgery to be very or moderately dangerous. A large proportion of patients believe death (41%), stroke (47%), vision loss (56%), personality change (56%), paralysis (62%), difficulties in speaking (69%), and memory loss (60%) were frequent side effects. The majority of patients (62%) consider the surgical procedure as the last option of treatment. CONCLUSIONS: There is a negative attitude toward epilepsy surgery based on the patients' misperceptions of suffering neurological deficits during the surgery, reflecting lack of knowledge toward this type of treatment. These perceptions can contribute to delays in surgical care.

TITLE: Percepciones y actitudes de los pacientes frente a la cirugia de la epilepsia: conceptos equivocados en Colombia.Introduccion. Los pacientes con epilepsia focal farmacorresistente se podrian beneficiar de la cirugia de la epilepsia; sin embargo, existen demoras en la realizacion del procedimiento. El objetivo de este estudio fue evaluar el conocimiento y las actitudes de los pacientes hacia la cirugia de epilepsia e identificar barreras que pudieran retrasar el tratamiento. Pacientes y metodos. Se aplico un cuestionario de 10 minutos a pacientes con epilepsia en Colombia. La encuesta evaluo el conocimiento de la opcion quirurgica, las percepciones sobre el riesgo de la cirugia frente al riesgo de crisis no controladas, la discapacidad producida por la enfermedad, las metas del tratamiento y las variables demograficas y socioeconomicas. Resultados. Se seleccionaron 88 pacientes con epilepsia focal. El 56% de los pacientes no sabia que la cirugia podria ser una opcion terapeutica. El 60% considero que la cirugia de la epilepsia es muy o moderadamente peligrosa. Una gran proporcion pensaba que la muerte (41%), el ictus (47%), la perdida visual (56%), los cambios en la personalidad (56%), la paralisis (61%), las dificultades para hablar (69%) y la perdida de la memoria (60%) eran efectos secundarios comunes. La mayoria (62%) consideraba el procedimiento como la ultima opcion de tratamiento. Conclusiones. Existe una actitud negativa por parte de los pacientes frente a la cirugia de la epilepsia fundamentada en la sobreestimacion del riesgo de adquirir deficits neurologicos secundarios al procedimiento, lo que refleja la falta de conocimiento hacia este tratamiento. Estas percepciones erroneas pueden contribuir a demoras en la atencion quirurgica.

[Diagnosis and treatment of non-triggered single epileptic seizures]. / Diagnostico y tratamiento de la crisis epileptica unica no provocada.

Epileptic seizures are one of the main reasons for neurological visits in an emergency department. Convulsions represent a traumatic event for the patient and the family, with significant medical and social consequences. Due to their prevalence and impact, the initial management is of vital importance. Although following the first epileptic seizure, early recurrence diminishes after establishing treatment with antiepileptic drugs, the forecast for developing epilepsy and long-term outcomes are not altered by any early intervention. Detailed questioning based on the symptoms of the convulsions, the patient's medical history and a full electroencephalogram and neuroimaging study make it possible to define the risk of recurrence of the seizure and the possible diagnosis of epilepsy. Epileptic abnormalities, the presence of old or new potentially epileptogenic brain lesions, as well as nocturnal seizures, increase the risk of recurrence. Physicians must assess each patient on an individual basis to determine the most suitable treatment, and explain the risk of not being treated versus the risk that exists if treatment with antiepileptic drugs is established.

TITLE: Diagnostico y tratamiento de la crisis epileptica unica no provocada.Las crisis epilepticas son una de las principales causas de consulta neurologica en el servicio de urgencias. Un episodio convulsivo representa un evento traumatico para el paciente y la familia, con consecuencias medicas y sociales significativas. Por su prevalencia e impacto, el abordaje inicial es de vital importancia. Si bien despues de una primera crisis epileptica la recurrencia temprana disminuye con el inicio de farmacos antiepilepticos, el pronostico para el desarrollo de epilepsia y los desenlaces a largo plazo no se alteran por ninguna intervencion temprana. El interrogatorio detallado basado en la semiologia del episodio, los antecedentes del paciente y un estudio completo con electroencefalograma y neuroimagen permiten definir el riesgo de recurrencia de la crisis y el posible diagnostico de epilepsia. Las anormalidades epilepticas, la presencia de lesiones cerebrales con potencial epileptogeno antiguas o nuevas, asi como las crisis nocturnas, incrementan el riesgo de recurrencia. Los medicos deben evaluar a cada paciente de manera individual para determinar un tratamiento idoneo, explicando el riesgo de no tratar frente al riesgo existente con el inicio de farmacos antiepilepticos.

Associated conditions in myasthenia gravis: response to thymectomy.

To compare the response of thymectomy in patients with associated conditions (PWAC) and without associated conditions (PWOAC). Comparative, retrospective. 198 patients with the established diagnosis of myasthenia gravis who had a thymectomy between 1987 and 2000, and who were folowed up for at least 3 years. We formed two groups, one with associated conditions and the second without associated conditions. The patients were divided into four groups: (i) patients in remission, (ii) patients with improvement, (iii) patients without changes, and (iv) patients whose condition worsened. Associated conditions (AC) were found in 49 patients (26%). The main associated conditions were hyperthyroidism in 16 patients (33%) hypothyroidism in seven (14%), rheumatoid arthritis in five (10%) and hypothyroidism and Sjogren syndrome in three (6%). Concerning the response of thymectomy, 13 patients WAC showed remission (27%), vs. 54 patients WOAC (39%). Twenty patients WAC showed improvement (41%) vs. 46 WOAC (33%). Thirteen patients WAC had no changes (27%) vs. 37 WOAC (26%). Finally, in three patients WAC their condition worsened (6%) vs. three WOAC (2%). The response to thymectomy was high (69%) in both groups. We did not identify significant differences.

[Painful neuropathies: their pathophysiology and treatment]. / Neuropatías dolorosas: fisiopatología y tratamiento.

OBJECTIVES: The purpose of this study is to review the different studies published in the literature concerning the different physiological mechanisms involved in the genesis of painful neuropathy, as well as the diagnostic options and the different pharmacological treatments currently available. DEVELOPMENT: Distinct pathologies usually condition painful neuropathy, one of the main ones being diabetes mellitus. The triggering phenomenon is often some kind of damage to the tissues that contain nervous pain receptors, which later gives rise to a release of proinflammatory molecules, and triggers a cascade of phenomena that result in disorders in the central and peripheral nervous system (peripheral and central sensitisation). These disorders usually produce clinical manifestations, such as allodynia, paresthesias, among others, and these are sometimes the sole manifestation of painful neuropathy. Diagnosis of this syndrome is at times complicated due to the involvement of thin fibres, which cannot be identified by the conventional methods used in neurophysiological studies. There is also a broad range of pharmaceuticals used in the treatment of painful neuropathy that range from tricyclic antidepressants, non-steroidal anti-inflammatory drugs, opioid analgesics, antiarrhythmics and even agents for topical use. CONCLUSIONS: Diagnosis of thin fibre neuropathy is usually performed by carrying out a Quantitative Sudomotor Axon Reflex Test, quantitative sensory tests and a skin biopsy. As regards the pharmacological treatment, the new generation of anticonvulsive drugs like gabapentin seems to have advantages over the traditional pharmaceuticals, although their widespread use is still largely restricted by their cost.

Response of thymectomy: clinical and pathological characteristics among seronegative and seropositive myasthenia gravis patients.

OBJECTIVE: To identify the response to thymectomy in patients with seronegative and seropositive myasthenia gravis (SPMG). We analyzed the associated diseases, thymus histology, and the severity of symptoms between the two groups. MATERIAL AND METHODS - DESIGN: Descriptive, comparative. STUDY UNITS: Fourteen patients with seronegative myasthenia gravis (SNMG) and 57 patients with SPMG who had a thymectomy between 1987 and 1997, with at least 3 years of follow-up. The patients were divided into four groups; (1) Remission, (2) Improvement, (3) No change and (4) Deterioration. RESULTS: Fourteen patients (20%) were seronegative and 57 were seropositive (80%). In the group of patients with SNMG, three patients were in remission (21%), five with improvement (36%), five with no change (36%) and one with worsening (7%). In the group of patients with SPMG, 12 were in remission (21%), 17 with improvement (30%), 25 with no change (44%) and three (5%) with worsening. The patients with SNMG were older, with less associated diseases and with a lower frequency of thymomas. CONCLUSIONS: The response to thymectomy was similar between the two groups. It has been suggested that seronegative patients have a better prognosis, but our results show no differences.

HLA class II genotypes in Mexican Mestizo patients with myasthenia gravis.

Myasthenia gravis is an autoimmune, heterogeneous disorder, characterized by the presence of antibodies against acetylcholine receptors at the neuromuscular junction. There is a strong evidence that an individual's genetic composition is an important predisposing factor for the development of the disease. To correlate HLA class II genotypes with thymic pathology in Mexican Mestizo patients who had been subjected to thymectomy. HLA class II genes were analyzed in 60 patients and in 99 healthy ethnically matched controls. Thymic hyperplasia, atrophy, thymoma, and normal histology were encountered in 56, 33, 8 and 2% of patients, respectively. HLA-DR11 was significantly increased in patients with thymoma compared with healthy controls (pC = 0.001, OR = 13.35, 95% CI 3.5-51.3), compared with the subgroup of hyperplasia patients (pC = 0.005, OR = 15.5, 95% CI 2.78-95.58) and with the atrophy subgroup (pC = 0.04, OR = 10.5, 95% CI 1.75-70.95). This study provides the evidence of an association between HLA class II alleles with clinical and genetic heterogeneity in myasthenia gravis, particularly in those with thymoma (HLA-DR11).

The association of myasthenia gravis and connective tissue diseases. Effects of thymectomy in six cases with rheumatoid arthritis and one case with systemic lupus erythematosus.

OBJECTIVES: To describe the effects of thymectomy in a group of patients with myasthenia gravis (MG) with associated connective tissue diseases (CTD). PATIENTS AND METHODS: We analyzed six patients with CTD and myasthenia. They were followed-up for at least 3 years. RESULTS: Records of a cohort of 132 patients with established diagnosis of MG undergoing thymectomy in our institution between 1987-1999 were reviewed. The percentage of patients with CTD was 5 % (6/132). Five patients had rheumatoid arthritis (RA) and one patient systemic lupus erythematosus (SLE). All patients were women, and the mean age was 38.5 years old (SD 13.7). Mean time of MG diagnosis to operation was 16 months (range from 1 to 144 months). Preoperative Osserman classification was the following: stage IIb, four patients; stage III, one patient; and stage IV, one patient. Before surgery all patients were on anticholinesterase agent (pyridostigmine), and four patients were on corticosteroids. An extended transsternal thymectomy was practiced on five patients and a transcervical thymectomy was performed in the remaining patient. Pathologic findings were as follows: thymic hyperplasia in four patients and thymic atrophy in the other two. Good response (remission or improvement) was present in three patients (50 %) and poor response (no change or worse) in the other three (50 %). CONCLUSIONS: A low response to the thymectomy is observed in patients with MG and associated CTD (RA and an SLE).

[Systemic lupus erythematosus with affection to brainstem: report of three cases]. / Lupus erimatoso sistémico con afectación del tronco encefálico: presentación de tres casos.

INTRODUCTION: The frequency with which the central nervous system (CNS) is affected by systemic lupus erythematosus (SLE) varies, according to different series, between 13 and 59%, whereas the brain stem is affected in 5%. CASE REPORTS: Case 1: a 33 year old male who was submitted to a Nissen funduplicature as a treatment of (hypo)incoercible hiccups. The singultus persisted and some time after a paraplegia appeared. Magnetic resonance (MRI) showed images in the medulla oblongata, and in the cervical and thoracic spine. A biopsy was also performed to examine the cervical lesions and vasculitis was diagnosed. The patient began treatment with prednisone (1 mg/kg) and two months after symptoms had begun to improve he presented an episode of bilateral optic neuritis. Until this last event, the immunological studies had been positive. Case 2: female aged 19 who had had SLE for eight months. The illness began suddenly with bilateral paralysis of the sixth cranial nerve, vertical and horizontal nystagmus, dysdiadochokinesia, truncal ataxia, 4/5 muscular strength in the upper limbs and 3/5 in the lower limbs, and left flexor plantar response, but indifferent on the right hand side. MR showed T2 hyperintensities in the pons, medulla oblongata and the junction of medulla and upper spinal cord. Case 3: female aged 31 with sudden onset of the illness, characterised by diplopy and presence of internuclear ophthalmoplegia. Brain MR showed images of T1 hypointense and T2 hyperintense in the pontobulbar region. CONCLUSION: A brain stem disorder in patients suffering from SLE is one of the rarest manifestations of this pathological condition of the CNS and is probably caused by vasculitis

Prognostic factors of thymectomy in patients with myasthenia gravis: a cohort of 132 patients.

OBJECTIVE: To identify the response to thymectomy and the factors associated with a poor response, a nested case-control study was performed on 132 patients with an established diagnosis of myasthenia gravis who had had a thymectomy between 1987 and 1997 and had been followed up for at least 3 years. METHODS: In order to assess the response to thymectomy, the following two points were taken into account: (a) the dose of pyridostigmine and other drugs (steroids, azathioprine) that the patient took before and after thymectomy, and (b) the Osserman classification before and after thymectomy. The patients were divided into 4 groups: (1) patients in remission; (2) patients with improvement; (3) patients with no change, and (4) patients who were worse. RESULTS: 91 patients had a good response (69%) and 41 patients had a poor response (31%). The response by groups was as follows: 50 patients were found to be in remission; 41 patients had improved; 34 patients had no changes, and 7 got worse. Being more than 60 years old was associated with a poor prognosis (odds ratio 4.6, CI 1.11-20.32, p 0.01). The patients who had the disease for more than 3 years (odds ratio 2.97, CI 0.79-5.39, p 0.09) had a tendency towards a bad prognosis even though there was no statistical significance, and for those who had it for more than 4 years (odds ratio 2.58, CI 0.89-0.96, p 0.02) the bad prognosis was statistically significant. The patients who had the disease for more than 3 years between diagnosis and thymectomy (odds ratio 2.02, CI 0.69-5.90, p 0.15) and those with it for more than 4 years (odds ratio 2.53, CI 0.83-7.7, p 0.06) had a tendency towards a poor prognosis even though there was no statistical significance. In addition, having Osserman I was associated with a bad prognosis. Referring to the pathological findings, patients with thymoma (odds ratio 3.51, CI 0.43-31.5, p 0.15) and those with thymic atrophy (odds ratio 2.19, CI 0.93-5.16, p 0.04) had a poor prognosis. Finally, the use of steroids before thymectomy (odds ratio 2.26, CI 0.99-5.18, p 0.03) was associated with a worse prognosis. CONCLUSIONS: The response to thymectomy was high (69%). The variables that had the most prognostic importance were age and the Osserman stage. Other variables of poor prognosis were: high doses of pyridostigmine and use of steroids before surgery; the total duration of the disease and the duration of the disease between diagnosis and the surgical procedure; history of previous thymectomy; use of plasmapheresis after surgery, and the discovery of thymic atrophy and thymoma in the histopathological result.

[Guillain-Barre syndrome. Experience in a third level hospital]. / Síndrome de Guillain-Barré. Experiencia en un hospital de tercer nivel.

INTRODUCTION: Acute peripheral neuropathy represents a medical emergency. The causes of it are diverse and plentiful. The most common cause of acute paralytic peripheral neuropathy is the Guillain-Barré syndrome (GBS). As many as 85% of those affected can be expected to make an excellent recovery. OBJECTIVE: To describe the principal risk factors associated, clinical manifestations, treatment, evolution and complications of 28 cases of Guillain-Barré syndrome (GBS) in the "Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán". METHODS: We search in our computer records all files under diagnostic of GBS, during the last ten years. We found 28 cases that were available to study. RESULTS: Mean age was 37 years old (SD 17.2). Fifteen patients were female (54%) and 13 were male (46%). Nine patients (32%) were preceded by a superior via infection, 5 (18%) by a diarrhea illness and 14 patients had not a predisposing factor. The duration of symptoms before diagnostic has a median of 7 days (2-15). Twenty-six patients (93%) had an ascending paralysis and 18 had paresthesias (64%). The most frequent subtype was acute inflammatory-demyelinating polyneuropathy (AIDP) in 18 patients (64%), acute motor-sensory axonal neuropathy (AMSAN) in 5 (18%), acute motor axonal neuropathy (AMAN) in 3 (11%) and 2 patients (7%) had the Fisher-Miller syndrome. Fifteen patients (54%) developed respiratory involvement requiring mechanical ventilation. Twenty-four patients (86%) had cerebrospinal fluid proteins elevated. Twenty patients (72%) had a total recovery, 6 (21%) had a partial recovery and 2 had not any response (7%). DISCUSSION: GBS is a particularly highstakes illness in that its onset is sudden and paralysis is frequently extreme (requiring assisted respiration), however, as many as 85% of those affected can be expected to make an excellent recovery. In our study the majority of patients (54%) develop respiratory involvement requiring mechanical ventilation but in this group the majority had a favorable outcome (71%).

[Descriptive analysis of 41 patients with a pyogenic hepatic abscess]. / Análisis descriptivo de 41 pacientes con absceso hepático piógeno.

OBJECTIVE: To identify the clinical, laboratory and imaging characteristics of 41 patients with a pyogenic hepatic abscess. RESEARCH DESIGN: Retrospective, descriptive. SETTING: Instituto Nacional de Ciencias Médicas y Nutrición, Salvador Zubirán. STUDY UNITS: 41 patients with a pyogenic hepatic abscess. MAIN MEASUREMENTS: The measurement of the following variables was carried out: previous background, period of evolution, symptoms, signs, laboratory studies, imaging, treatment, complications and evolution. RESULTS: 41 patients were evaluated. The average age of the group was 52.5 years (SD = 14.3) and 30 (73%) were male. The most frequent associated disease was diabetes mellitus which was found in 15 patients (37%). The most frequent clinic data were: fever in 38 patients (93%), chills in 26 (63%) and pain in the upper right quadrant in 25 (61%). The most common source of the formation of the abscess was of biliary origin in six patients (15%) and the serum amoeba test was positive in 10% of the cases. The localization of the abscess in our series was as follows: 33 cases (81%) were from the right lobe, five (12%) from the left lobe, three (7%) from both lobes and 87% were solitary. The germ found more frequently was E. coli in five patients (15%). As for the treatment, puncture by computed tomography was carried out in 25 patients (61%), four patients had a surgery and the rest were treated only with antibiotics. Regarding mortality, only one patient died (2%) due to a septic shock. CONCLUSIONS: An association with diabetes mellitus was identified and the most frequent origin was biliary, these data have already been reported in other studies. On the other hand, mortality and morbidity rates in our study were low.

[Klippel-Feil syndrome. Three-dimensional tomographic images]. / Síndrome de Klippel-Feil. Imágenes por tomografía en tercera dimensión.

Klippel-Feil syndrome (KPS) is characterized by congenital vertebral fusion believed to result from faulty segmentation along the embryo's developing axis. The hallmark phenotypic findings of low hairline, short neck, and limited range of motion of the neck are found as al triad in < 50% of patients. Congenital musculoskeletal and systemic anomalies are commonly found. These include, but are not limited to elevation of the scapula, scoliosis and renal and cardiac abnormalities. Here, we present the three-dimensional images by computed tomography of a 9-year-old boy with multiple fusion of the cervical vertebraes.

Longitudinal myelitis associated with systemic lupus erythematosus: clinical features and magnetic resonance imaging of six cases.

Myelopathy is a rare central nervous system (CNS) complication associated with systemic lupus erythematosus (SLE). Acute transverse myelitis (ATM) is the most frequent form of SLE-related myelopathy. Magnetic resonance imaging (MRI) typically shows increased signal intensity in T2-weighted images and cord swelling. In the present paper, we describe six cases of SLE-related myelopathy with multiple increased signals in the T2-weighted images involving continuous levels of the cervical and thoracic spinal cord, a distinctive feature recently named 'longitudinal myelitis'. The clinical and laboratory findings are similar to those presented by ATM patients, including paraparesis, sensory level and sphincter disturbances. Four patients had positive antiphospholipid antibodies (aPL) suggesting that this could be a characteristic of longitudinal myelitis. Treatment in all cases included high doses of corticosteroids and immunosuppressive agents (intravenous (i.v.) cyclophosphamide). Anticoagulation therapy was given to one patient and two others received low doses of aspirin. The outcome was mainly unfavorable with slow improvement in only one case, no improvement in two and relapse of the myelopathy in the remaining three. In conclusion, longitudinal myelitis is an unusual form of SLE-related myelopathy, it might be associated with aPL and it has a poor prognosis.

[Physiopathology of nephropathy studied with contrast media]. / Fisiopatología de la nefropatía por medio de contraste.

For the technological advances in diagnostic and therapeutic procedures, the use of intravenous contrast media in the hospital is more and more frequent. It can produce acute renal failure secondary to its nephrotoxicity known as contrast media nephropathy. This review describes the pathophysiologic mechanisms of contrast media injury, including cytotoxicity caused by hyperosmoloarity of contrast media, the hemodynamic factors and the role of the renin-angiotensin system, prostaglandins, oxygen free radicals, endothelin-1, adenosine, nitric oxide and others. The understanding of this information is of vital importance for the development of prophylactic strategies for contrast media nephropathy.

[Pathogenesis of myasthenia gravis]. / Patogénesis de la miastenia gravis.

Myasthenia gravis is a neuromuscular, autoimmune, and acquired disturbance characterized by weakness and fatigue of skeletal muscles. During the past two decades, remarkable progress has been made in the understanding of myasthenia gravis, and the new knowledge has been applied directly to the clinical diagnosis and treatment of this formerly severe disease. Myasthenia gravis is undoubtedly the most thoroughly understood of all human autoimmune diseases and has served as a model for the elucidation of mechanisms underlying other autoimmune disorders. In this review we mention the most important physiopathological aspects and its application in the clinic practice.

[Hyperhomocysteinaemia: physiopathology and medical implications]. / Hiperhomocistinemia: fisiopatología e implicaciones médicas.

Homocysteine is an intermediate aminoacid result of the conversion of methionine to cysteine. Homocystinuria or the hyperhomocysteinaemia are the most frequently related disorders of this aminoacid, being the former an autosomic recessive alteration, whereas the latter is conditioned by multiple factors, being the most important the genetic and nutritional factors. In the last years this alteration has regained special interest because of its increasing role in the thrombotic pathologies and the identification that hyperhomocysteinaemia represents an independent risk factor for the accelerated atherogenesis of multiple diseases. In this review physiopathological aspects and clinical implications of hyperhomocysteinaemia are mentioned as well as its diagnoses and treatment.

[Central neurogenic hyperventilation associated with a pontine infarction]. / Hiperventilación central neurogénica en infarto pontino.

Central neurogenic hyperventilation in patients with a normal level of consciousness is uncommon. This condition occurs in bilateral pontine tegmental lesions, particularly tumors such as CNS lymphomas and glioma, as well as traumatic lesions. The physiopathological mechanisms are unknown and no there is no effective treatment for this entity. We report a case of central neurogenic hyperventilation associated to a unilateral basal pontine infarction.

[A fibrolamellar variety of hepatocarcinoma in a young woman 17 years old]. / Hepatocarcinoma variedad fibrolamelar en una joven de 17 años de edad.

We report here the case of a 17-year-old female with typical fibrolamellar hepatocellular carcinoma, no hepatitis B or C viral infection and a normal, non-cirrhotic liver. Computed tomography and magnetic resonance imaging revealed a solid tumor with a central fibrous scar. A fibrolamellar hepatocellular carcinoma is an uncommon malignancy of unknown etiology, without cirrhosis, usually without an increase in tumor markers, and rarely associated with hepatitis B virus. It occurs mainly in young patients. This tumor presents a high resectability rate (48-100%), a good prognosis and a mean survival of 68 months. This tumor is an important differential diagnosis of space occupying lesions in younger adults.