Lymphomas of the anterior mediastinum

Implementation of an Anterior Mediastinal Mass Pathway to Improve Time to Biopsy and Multidisciplinary Communication

Background

Mediastinal masses in children with cancer present unique challenges, including the risk of respiratory and hemodynamic compromise due to the complex anatomy of the mediastinum. Multidisciplinary communication is often a challenge in the management of these patients. After a series of patients with mediastinal masses were admitted to Riley Hospital for Children Pediatric Intensive Care Unit, the time from presentation to biopsy and pathology was greater than expected. We aimed to reduce the time to biopsy by 25% and demonstrate improved multidisciplinary communication within 6 months of protocol implementation for patients presenting to Riley Hospital for Children Emergency Department with an anterior mediastinal mass.

Methods

Quality improvement methodology created a pathway that included early multidisciplinary communication. The pathway includes communication between the emergency department and multiple surgical and medical teams via a HIPPA-compliant texting platform. Based on patient stability, imaging findings, and sedation risks, the approach and timing of the biopsy were determined.

Results

The pathway has been used 20 times to date. We successfully reduced the time to biopsy by 38%, from 25.1 hours to 15.4 hours. There was no statistically significant reduction in time to pathology. The multidisciplinary team reported improved communication from a baseline Likert score of 3.24 to 4.

Conclusions

By initiating early multidisciplinary communication, we reduced the time to biopsy and pathology results, improving care for our patients presenting with anterior mediastinal masses.

Differentiation between rebound thymic hyperplasia and thymic relapse after chemotherapy in pediatric Hodgkin lymphoma

BACKGROUND

Rebound thymic hyperplasia (RTH) is a common phenomenon caused by stress factors such as chemotherapy (CTX) or radiotherapy, with an incidence between 44% and 67.7% in pediatric lymphoma. Misinterpretation of RTH and thymic lymphoma relapse (LR) may lead to unnecessary diagnostic procedures including invasive biopsies or treatment intensification. The aim of this study was to identify parameters that differentiate between RTH and thymic LR in the anterior mediastinum.

METHODS

After completion of CTX, we analyzed computed tomographies (CTs) and magnetic resonance images (MRIs) of 291 patients with classical Hodgkin lymphoma (CHL) and adequate imaging available from the European Network for Pediatric Hodgkin lymphoma C1 trial. In all patients with biopsy-proven LR, an additional fluorodeoxyglucose (FDG)-positron emission tomography (PET)-CT was assessed. Structure and morphologic configuration in addition to calcifications and presence of multiple masses in the thymic region and signs of extrathymic LR were evaluated.

RESULTS

After CTX, a significant volume increase of new or growing masses in the thymic space occurred in 133 of 291 patients. Without biopsy, only 98 patients could be identified as RTH or LR. No single finding related to thymic regrowth allowed differentiation between RTH and LR. However, the vast majority of cases with thymic LR presented with additional increasing tumor masses (33/34). All RTH patients (64/64) presented with isolated thymic growth.

CONCLUSION

Isolated thymic LR is very uncommon. CHL relapse should be suspected when increasing tumor masses are present in distant sites outside of the thymic area. Conversely, if regrowth of lymphoma in other sites can be excluded, isolated thymic mass after CTX likely represents RTH.

Anterior mediastinal masses - A multidisciplinary pathway for safe diagnostic procedures

OBJECTIVE

The objective of this study was to report our multidisciplinary diagnostic approach for patients with anterior mediastinal masses (AMM).

METHODS

A retrospective review of patients with AMM at a tertiary pediatric surgical oncology centre (January 2011-December 2016) was performed. We analyzed data on clinical presentation, mode of tissue diagnosis, anesthetic techniques, and complications.

RESULTS

Of the 44 patients admitted with AMM (median age 11 years, 27 males and 17 females), 22 had respiratory symptoms. Imaging revealed tracheobronchial compression in 26 children. Twenty patients had a lymph node biopsy. Ten patients had image-guided core biopsy of the mediastinal mass, and 2 had mediastinoscopic biopsy of a paratracheal lymph node. One patient with likely recurrence of a relapsed metastatic ethmoid carcinoma did not have a biopsy. The diagnosis was made from alternative tissues, such as pleural fluid in 4 and peripheral blood in 7 patients. Twenty-five anesthetics were assessed, as 14 patients required no or only local anesthesia, and 5 had unavailable anesthetic notes. Eighteen of 25 patients were anesthetized maintaining spontaneous breathing, mostly by means of ketamine sedation. There were no major anesthetic complications.

CONCLUSION

Safe tissue diagnosis of anterior mediastinal masses can be obtained by a personalized multidisciplinary approach. Use of alternative tissues, local anesthesia, and ketamine sedation help minimize the need for general anesthesia, muscle paralysis, and controlled ventilation.

LEVEL OF EVIDENCE

IV (Case Series with no Comparison Group).

Primary Mediastinal Classical Hodgkin Lymphoma

Primary mediastinal Classical Hodgkin lymphoma (CHL) is rare. Nodular sclerosis CHL (NS-CHL) is the most common subtype involving the anterior mediastinum and/or mediastinal lymph nodes. Primary thymic CHL is exceedingly rare. The disease typically affects young women and is asymptomatic in 30% to 50% of patients. Common symptoms include fatigue, chest pain, dyspnea and cough, but vary depending on the location and size of the tumor. B-symptoms develop in 30% of cases. By imaging, primary mediastinal CHL presents as mediastinal widening/mediastinal mass that does not invade adjacent organs but may compress vital structures as bulky disease. Histopathology is the gold standard for diagnosis. Primary mediastinal NS-CHL consists of nodules of polymorphous inflammatory cells surrounded by broad fibrous bands extending from a thickened lymph node capsule. The cellular nodules contain variable numbers of large Hodgkin/Reed-Sternberg cells, required for diagnosis. Primary thymic CHL may exhibit prominent cystic changes. The histopathologic recognition of NS-CHL can be challenging in cases with prominent fibrosis, scant cellularity, artifactual cell distortion, or an exuberant granulomatous reaction. The differential diagnosis includes primary mediastinal non-HLs, mediastinal germ cell tumors, thymoma, and metastatic carcinoma or melanoma to the mediastinum. Distinction from primary mediastinal non-HLs is crucial for adequate therapeutic decisions. Approximately 95% of patients with primary mediastinal CHL will be alive and free of disease at 10 years after treatment with short courses of combined chemoradiotherapy. In this review, we discuss the history, classification, epidemiology, clinicoradiologic features, histopathology, immunohistochemistry, differential diagnosis, and treatment of primary mediastinal CHL.

The use of convex probe endobronchial ultrasound-guided transbronchial needle aspiration in a pediatric population: a multicenter study

INTRODUCTION

The presence of intrathoracic lymphadenopathy and mediastinal masses in the pediatric population often presents a diagnostic challenge. With limited minimally invasive methodologies to obtain a diagnosis, invasive sampling via mediastinoscopy or thoracotomy is often pursued. Endobronchial ultrasound transbronchial needle aspiration (EBUS-TBNA) is a minimally invasive, outpatient procedure that has demonstrated significant success in the adult population in the evaluation of such abnormalities. Within the pediatric literature there is limited data regarding the use of EBUS-TBNA. We report the first multicenter review of a pediatric population undergoing EBUS-TBNA procedures identifying the feasibility, safety, utility, and outcomes of this procedure.

METHODS

All patients of 18 years of age or younger undergoing EBUS-TBNA at six major academic medical centers from the years 2007 through 2013 were reviewed. Data regarding procedural performance, outcomes, and complications were recorded.

RESULTS

A total of 21 patients meeting the inclusion criteria were identified in six centers. The mean age of the cohort was 13.7 (±4.1) years. EBUS-TBNA provided adequate sampling in 20/21 (95%) of the cases with diagnostic material obtained in 10 (48%) cases. Eight patients (38%) underwent additional surgical procedures to confirm or obtain diagnostic tissue. Within our cohort, 13 patients (62%) were able to avoid invasive surgical biopsy procedures. No procedural or anesthesia related complications were identified.

CONCLUSION

We report the first multicenter study to date confirming the feasibility and utility of EBUS-TBNA in the pediatric population. Due to the low overall procedural risk of EBUS-TBNA, it should be considered as a potential first line diagnostic option for children presenting with mediastinal or hilar abnormalities but further prospective studies are needed.

Interventional pulmonology procedures in the pediatric population

INTRODUCTION

Advanced training in interventional pulmonology (IP) includes a multidisciplinary approach to a wide variety of pathologic conditions affecting different age groups. The role of the interventional pulmonologist in the pediatric patient population has not been described. We report our experience of the care of pediatric patients by IP at an academic institution.

METHODS

A retrospective review of inpatient and outpatient IP procedures from 2008 to 2011 was performed. All patients' less than 21 years of age at the time of their procedure were identified. Data regarding age, procedure performed, pre-operative diagnosis, results, and complications were collected.

RESULTS

Thirty-five patients younger than the age of 21, with 14 of these patients being under the age of 18, were identified. Fifty-six procedures were performed on the entire cohort, 30 as inpatient procedures and 26 as outpatient procedures. There were no deaths or major complications related to any procedure.

DISCUSSION

We identified a cohort of pediatric patients that were able to successfully undergo diagnostic and therapeutic procedures under the direction of an experienced IP team. Cases included the evaluation and management of both malignant and benign complex airway and pleural diseases. There was no major morbidity or mortality related to our procedures, demonstrating an ability to safely evaluate and manage complex airway and pleural disease in the pediatric population.

Differentiation of normal thymus from anterior mediastinal lymphoma and lymphoma recurrence at pediatric PET/CT

PURPOSE

To evaluate the role of positron emission tomography (PET)/computed tomography (CT) in the differentiation of normal thymus from mediastinal lymphoma and lymphoma recurrence in pediatric patients.

MATERIALS AND METHODS

The study was approved by the institutional review board, and informed consent was waived. The study was HIPAA compliant. Two hundred eighty-two fluorine 18 fluorodeoxyglucose PET/CT studies in 75 pediatric oncology patients were reviewed retrospectively. Patients were divided into four groups: anterior mediastinal lymphoma (group A, n=16), anterior mediastinal lymphoma with subsequent recurrence (group B, n=5), lymphoma outside the mediastinum (group C, n=16), and other malignant tumors outside the thymus (group D, n=38). Analyses included measurements of the maximum anteroposterior and transverse dimensions of the anterior mediastinal mass or thymus on axial CT images and measurements of maximum standardized uptake values of anterior mediastinal mass, thymus (SUVt), and bone marrow at the level of the fifth lumbar vertebra (SUVb) on PET images. Quantitative parameters were compared by using an analysis of variance test.

RESULTS

Mean prechemotherapy SUVt was 4.82 for group A, 8.45 for group B, 2.00 for group C, and 2.09 for group D. Mean postchemotherapy SUVt for group B was 4.74. Thymic rebound (mean SUVt, 2.89) was seen in 44% of patients at a mean interval of 10 months from the end of chemotherapy. The differences between prechemotherapy SUVt of mediastinal lymphoma and normal thymus and postchemotherapy SUVt of lymphoma recurrence and thymic rebound were highly significant (P<.001).

CONCLUSION

SUVt is a sensitive predictor for differentiation of normal thymus or thymic rebound from mediastinal lymphoma. SUVt of 3.4 or higher is a strong predictor of mediastinal lymphoma.

Imaging of the pediatric airway

Airway compromise can be fixed, dynamic (with varying degrees of collapse during the respiratory cycle), or exhibit both components. The location of the abnormality can be classified as extrinsic (located outside but exerting mass effect on the airway) or intrinsic (intramural and/or intraluminal). The etiologies of airway compromise are categorized as: congenital, infectious, inflammatory, traumatic, vascular, or neoplastic (1). The role of imaging of the airway is to determine the presence, nature and anatomic level of airway compromise, categorize it as intrinsic or extrinsic, provide a differential diagnosis, and guide further imaging or management (1). The differential diagnosis of a lesion takes into account the patient's age and gender, location of the lesion, clinical presentation, and imaging appearance.

Management of children and adolescents with a critical airway due to compression by an anterior mediastinal mass

This study used retrospective review of patients with critical airway due to compression by an anterior mediastinal mass treated at a single pediatric teaching institution. Diagnostic workup is reviewed with a focus on diagnostic biopsy. Algorithm for streamlining the choice of biopsy technique and minimizing invasive procedures is suggested.

Multimodality imaging of tracheobronchial disorders in children

The trachea and bronchial airways in children are subject to compromise by a number of extrinsic and intrinsic conditions, including congenital, inflammatory, infectious, traumatic, and neoplastic processes. Stridor, wheezing, and respiratory distress are the most common indications for imaging of the airway in children. Frontal and lateral chest and/or neck radiography constitute the initial investigations of choice in most cases. Options for additional imaging include airway fluoroscopy, contrast esophagography, computed tomography (CT), and magnetic resonance (MR) imaging. Advanced imaging techniques such as dynamic airway CT, CT angiography, MR angiography, and cine MR imaging are valuable for providing relevant vascular and functional information in certain settings. Postprocessing techniques such as multiplanar reformatting, volume rendering, and virtual bronchoscopy assist in surgical planning by providing a better representation of three-dimensional anatomy. A systematic approach to imaging the airway based on clinical symptoms and signs is essential for the prompt, safe, and accurate diagnosis of tracheobronchial disorders in children.

Imaging Evaluation of Pediatric Mediastinal Masses

Mediastinal masses in children are a heterogeneous group of asymptomatic to potentially life-threatening congenital, infectious, or neoplastic lesions that can present complex diagnostic and therapeutic dilemmas. This article presents the imaging features of the common mediastinal masses seen in the pediatric population. Classification of the masses is performed according to the traditional mediastinal compartment model, consisting of the anterior, middle, and posterior mediastinum. This scheme facilitates differentiation of the variety of disorders.

Mediastinal tumors in children: a single institution experience

Mediastinal masses in children are a heterogeneous group of asymptomatic or potentially life-threatening congenital, infectious, or neoplastic lesions that present complex diagnostic and therapeutic dilemmas. Some patients are asymptomatic; in others, the mass may compress mediastinal structures and cause sudden asphyxia. In these cases, close cooperation is needed among pediatric surgeons, anesthesiologists, intensivists, oncologists, and radiologists. The files of 45 children with mediastinal masses admitted between 1986 and 1999 to the Pediatric Intensive Care Unit (PICU) of Schneider Children's Medical Center of Israel were reviewed. Twenty-one were admitted for perioperative care, and 21 for emergency care, including 19 with respiratory distress. Five of the emergency care group had asphyxia and 10 needed assisted ventilation. Two children were admitted for evaluation and 1 for leukopheresis. The children admitted on an emergency basis had more clinical findings than the postoperative group: almost 80% had dyspnea and more than 45% had oxygen desaturation; 33% had cough and noisy breathing, and 25%, superior vena cava syndrome or hepatosplenomegaly. Eight patients (17.8%) had benign disease and 37 (82.2%) malignant disease. The patients with a benign mass were significantly younger than the patients with a malignant mass (p<0.005); in 5 cases (12.5%), a congenital anomaly presented as a mediastinal mass. Most of the malignant masses were of hematologic origin (40.5%), followed by neurogenic tumors (27%). Twenty-seven patients underwent surgery, including 6 emergency procedures (3 partial resections, 2 biopsies, 1 lymph node biopsy). There were no intraoperative or postoperative deaths. The present series emphasizes the complex care children with a mediastinal mass require. They should be treated in a tertiary center with a multidisciplinary approach.

Clinical management of anterior mediastinal tumors in children

The majority of anterior mediastinal tumors in children are malignant. The most common tumors in this location are lymphomas, germ cell tumors, and thymic masses. Most require an operation, either a biopsy or a resection, for cure. Because of their size and location, patients with these masses are at significant risk for cardiopulmonary complications when general anesthesia is administered. Of the many clinical, functional, and radiologic criteria used to identify the children at greatest risk for anesthetic complications, the peak expiratory flow rate (PEFR) and the tracheal cross-section area seem to be the most reliable. General anesthesia should not be administered to children if the PEFR and a tracheal cross section area are both less than 50% of predicted values. If both are greater than 50% of predicted values, general anesthesia can be administered safely. An algorithm is proposed for the preoperative evaluation and management of children with anterior mediastinal tumors.

The effects of prebiopsy corticosteroid treatment on the diagnosis of mediastinal lymphoma

BACKGROUND/PURPOSE

For children with probable mediastinal lymphoma and a high risk of cardiorespiratory morbidity, many centers recommend delaying the diagnostic biopsy for 24 to 48 hours while corticosteroids are administered to reduce tumor size and morbidity. This study was undertaken to determine the effect of preoperative steroid use on the accuracy of the pathological diagnosis and incidence of perioperative cardiorespiratory morbidity.

METHODS

From 1988 to 1998, 86 children were treated for mediastinal lymphoma. Twenty-three received steroid before biopsy (study group) because of clinical evidence of respiratory compromise, and the remaining 63 served as controls. Clinical parameters, steroid use, and detailed pathological findings obtained at initial and subsequent biopsies were reviewed. Steroid treatment was considered to have had an adverse effect on the pathological diagnosis if (1) a definitive diagnosis was delayed more that 1 month, (2) a definitive diagnosis could not be made, or (3) the extent of disease could not be staged with certainty.

RESULTS

Steroid treatment had an adverse effect on the pathological diagnosis in 5 of 23 (22%) children: 1 diagnostic delay, 3 failures of a definitive diagnosis, and 1 possible failure of staging. A definitive diagnosis was made in all control patients. Perioperative survival was 100% in both groups. At biopsy, only 3 children in the steroid treatment group and 2 children in the control group had moderate, nonfatal cardiorespiratory instability. Parameters of steroid use among children who had inaccurate pathological diagnoses or cardiorespiratory morbidity were not significantly different from those who did not.

CONCLUSIONS

Steroid treatment before biopsy of mediastinal lymphoma may adversely affect the pathological accuracy or cause a delay in definitive diagnosis in a minority of cases. The dose and duration of steroid use was not related to outcome. Prebiopsy steroid appears to minimize the likelihood of cardiorespiratory morbidity in high-risk patients.