Primary mediastinal malignancies in children: report of 22 patients and comparison to 197 adults

Aggressive Mediastinal Lymphomas

The mediastinum contains essentially all major intrathoracic organs except for the lungs. A variety of both benign and malignant tumors can involve the mediastinum, of which lymphoma is the most common malignancy. Compared to secondary mediastinal involvement by systemic lymphomas, primary mediastinal lymphomas are less common with several specific entities that are mainly confined to mediastinal lymph nodes, and/or thymus. This review will summarize the clinical, histologic, immunophenotypic and molecular genetic features of the most common and most aggressive primary mediastinal lymphomas as well as provide suggested immunohistochemistry panels and differential diagnoses.

Pediatric mediastinal tumors

Mediastinal tumors are the most common thoracic tumor in the pediatric population. They include a spectrum of tumors, and most are malignant. These lesions can be anatomically and radiologically classified by means of compartments; anterior, middle, and posterior. Symptoms, signs, localization of the tumor, age of the child, and tumor markers are key points of diagnosis. Surgical approaches are typically needed for diagnosis, but sometimes tru-cut needle biopsies may be sufficient. Mediastinoscopy, mediastinotomy, and video-assisted thoracoscopic surgery may be used in the diagnostic workup of mediastinal tumors in children as they are used in adults. Frequently, diagnosis and treatment are both established by means of surgery. Surgery remains the mainstay of treatment of most benign and malignant nonlymphoid tumors. Combined modality of treatment incorporating chemotherapy and radiotherapy is often required in malignant tumors and is associated with high survival rates in these patients.

Proton Beam Therapy for Unresectable Mediastinal and Pericardial Spindle Cell Sarcoma: A Case Report

Unresectable mediastinal soft tissue sarcomas are often aggressive and associated with a poor prognosis. A 17-year-old male presented with progressive fatigue, shortness of breath, and heart palpitations secondary to an extensive mass involving the mediastinum and pericardium. He was treated with chemotherapy per protocol Children's Oncology Group Protocol ARST0332 and proton beam therapy to the involved mediastinum, pericardium, and heart. At the 5-year follow-up evaluation, he remained disease-free on surveillance imaging. An echocardiogram revealed a 55% to 60% left ventricular ejection fraction. Given the patient's extended survival, we present the oncologic rationale for treatment and considerations of late toxicity.

Comparison between diffusion-weighted magnetic resonance and positron-emission tomography in the evaluation of treated lymphomas with mediastinal involvement

Background

The persistence of residual tissue after treatment is frequent in patients with mediastinal lymphomas and it is often characterized by 18F-Flurodeoxyglucose Positron Emission Tomography (18F-FDG PET) uptake. This study aims to investigate the usefulness of diffusion-weighted whole-body imaging with background body signal suppression (DWIBS) sequence in residual tissues of treated mediastinal lymphomas and to compare it with 18F-FDG PET-CT.

Results

We included 21 patients with mediastinal Hodgkin and non-Hodgkin lymphomas who showed residual masses on PET-CT imaging at end of treatment and underwent DWIBS-Magnetic Resonance Imaging (MRI). SUVmax and Apparent Diffusion Coefficient (ADC) values of residual masses were assessed quantitatively, including measurement of mean ADC. 15 patients showed radiotracer uptake at 18F-FDG PET-CT, among them only 3 had positive DWIBS-MRI with low ADC values (median value: 0.90 mm2/s). The mediastinal biopsy in these 3 “double positive” patients confirmed pathological residual tissue. All the patients with positive 18F-FDG PET-CT but negative DWIBS-MRI (n = 18) with high ADC values (median value: 2.05 mm2/s) were confirmed negative by biopsy.

Conclusions

DWIBS-MRI examination combined with ADC measurement allowed to discriminate pathological and non-pathological residual tissue in patients with treated mediastinal lymphoma. These preliminary results seem to pave the way for a leading role of the MRI which could be a useful alternative to the 18F-FDG PET/CT.

Approach to Mediastinal Fine Needle Aspiration Cytology

Mediastinal fine needle aspirations are routinely encountered in cytopathology practice. Mediastinal lesions may pose diagnostic challenges owing to their rarity and locations associated with the complexity of the mediastinal anatomic structures in the thoracic cavity. Diagnosing mediastinal lesions and guiding patient management usually require correlating with clinical and radiologic findings, being familiar with cytomorphologic features and appropriately triaging the diagnostic material for ancillary testing. This review proposes a practical approach to interpret mediastinal fine needle aspirations and emphasizes potential diagnostic pitfalls for mediastinal lesions including benign cysts, thymic neoplasms, lymphoproliferative disorders, germ cell tumors, mesenchymal tumors, and metastatic tumors.

Massive pericardial effusion as the first manifestation of childhood non-Hodgkin's lymphoma: A case report

Although one of the serious manifestations of advanced malignancies is pericardial involvement, pericardial involvement of lymphoma is extremely rare. We present a case of a 6-year-old girl arriving at the hospital with dyspnea and pleuritic chest pain, which is eventually diagnosed with massive pericardial effusion due to mediastinal non-Hodgkin lymphoma.

Mediastinal Lymphoproliferative Disorders

Lymphoproliferative disorders comprise 50% to 60% of all mediastinal malignancies in both children and adults. Primary mediastinal involvement is rare (∼5%), whereas secondary mediastinal involvement by systemic disease is more common (10% to 25%). Primary mediastinal disease is defined as involvement by a lymphoproliferative disorder of mediastinal lymph nodes, the thymus, and/or extranodal mediastinal organs without evidence of systemic disease at presentation. In this review, the clinical, radiologic, histopathologic, immunohistochemical, and genetic features of some of the most characteristic mediastinal lymphoproliferative disorders are presented. The entities discussed here include: classic Hodgkin lymphoma with emphasis on nodular sclerosis and mixed cellularity types, and non-Hodgkin lymphomas, including primary mediastinal (thymic) large B-cell lymphoma, mediastinal gray zone lymphoma, mediastinal diffuse large B-cell lymphoma, thymic marginal zone lymphoma, mediastinal plasmacytoma, T-lymphoblastic lymphoma, and anaplastic large cell lymphoma. Although not a malignant process, hyaline vascular Castleman disease is also discussed here as this disorder commonly involves the mediastinum. Despite multiple advances in hematopathology in recent decades, the day-to-day diagnosis of these lesions still requires a morphologic approach and a proper selection of immunohistochemical markers. For this reason, it is crucial for general pathologists to be familiar with these entities and their particular clinicoradiologic presentation.

Diagnostic Challenges in Fine-Needle Aspiration Cytology of Mediastinal Tumors and Lesions

CONTEXT.—

Mediastinal tumors/lesions are frequently encountered in daily cytopathology practice. These lesions are accessible through endoscopic/endobronchial ultrasound-guided or computed tomography-guided fine-needle aspiration cytology and represent a wide range of primary and metastatic tumors. This often poses diagnostic challenges because of the complexity of the mediastinal anatomic structures. Tumors metastatic to mediastinal lymph nodes represent the most common mediastinal lesions and must be differentiated from primary lesions.

OBJECTIVE.—

To provide an updated review on the fine-needle aspiration cytology of mediastinal tumors/lesions, with an emphasis on diagnostic challenges. This review encompasses thymic epithelial neoplasms, mediastinal lymphoproliferative disorders, germ cell tumors, neuroendocrine tumors, soft tissue tumors, and metastatic tumors. Differential diagnoses; useful ancillary studies, including targeted immunohistochemical panels; and diagnostic pitfalls are discussed.

DATA SOURCES.—

Data were gathered from a PubMed search of peer-reviewed literature on mediastinal tumors. Data were also collected from the authors' own practices.

CONCLUSIONS.—

Fine-needle aspiration cytology plays a vital role in evaluation of mediastinal lesions. Being familiar with the clinical and cytomorphologic features of these lesions, appropriately triaging the diagnostic material for ancillary testing, and correlating with radiologic findings are important in arriving at correct diagnoses and guiding management.

Pediatric Small Round Blue Cell Tumors: Cytopathological Puzzle or an Intriguing Scientific Window?

BACKGROUND

Small round blue cell tumors or more commonly called small round cell tumors (SRCTs) are undifferentiated neoplasms, sharing an overlapping morphological pattern of small round blue cells. Diagnosing these tumors represents a complex challenge for cytopathologists and for general surgical pathologist alike. This stems from the fact that these tumors share not only similar morphological features, but also some immunophenotypic characteristics, thus requiring a broad panel of antibodies, which might not be included in the most basic immunohistochemistry panels, used in the routine work of most pathology laboratories. Furthermore, one should note that the diagnosis, prognosis, and/or therapeutic decision are often dependent on the knowledge of the existence of specific molecular alterations, which requires access to sophisticated molecular ancillary techniques. Cytological diagnosis of SRCT should be systematized. A thorough understanding of the morphological pattern of these tumors, the small details they entail, the background and cellular patterns, and the nuclear and cytoplasmic peculiarities, may hint to the most probable diagnosis. Minor clues, such as the presence of a fibrillar background, the presence of rosettes or a specific "salt and pepper" chromatin, are important clues toward a probable diagnosis of a neuroblastoma, or the presence of a tigroid background is a characteristic of rhabdomyosarcoma and the Ewing family tumors. However, in poorly differentiated tumors, morphology alone will not suffice, making it essential for the access to complementary diagnostic techniques in order to reach the final diagnosis. Summary and Key Messages: The cytological diagnosis and treatment of SRCTs require an experienced, well-articulated, proficient teamwork, and sophisticated complementary diagnostic techniques, only available in centers of reference.

Primary Intrathoracic Sarcomas: A Review of Cross-sectional Imaging and Pathology

The most common sarcomas in the thorax are metastasis from an extrathoracic primary malignancy. Primary intrathoracic sarcomas are rare albeit aggressive malignancies that are diagnosed on histopathology. Although a few imaging characteristics have been described that are common to sarcomas, it is still a diagnosis of exclusion as other tumors are much more common. Like elsewhere, primary thoracic sarcomas are also classified according to their histologic features. They are a rare group of tumors that can arise from the mediastinal structures, lung, pleura, or chest wall. On imaging, differentiating these from more common malignancies like lung cancer is difficult and often requires multimodality workup and tissue sampling. A few sarcomas are very specific to their locations, such as angiosarcoma in the right atrium, leiomyosarcoma in the pulmonary artery, where imaging has high accuracy for the diagnosis. Despite being nonspecific in a majority of cases, imaging plays a pivotal role in determining the organ of origin, tumor extent, invasion of adjacent structures, and thus help to assess the surgical resectability. Although sarcomas arising from chest wall are the most common primary sarcomas in the chest, they are excluded from this review to focus only on primary intrathoracic sarcomas. The article provides a comprehensive imaging and pathology review of the rare primary intrathoracic sarcomas, including but not limited to angiosarcoma, Kaposi sarcoma, fibrosarcoma, malignant transformation of fibrous tumor of pleura, sarcomatoid mesothelioma, leiomyosarcoma, and malignant small round blue cell tumors.Key points:Primary intrathoracic sarcomas are rare but clinically important.Imaging helps to determine local extent, invasion, metastases and appropriate site/mode of biopsy.Role of pathology is paramount in diagnosis and guiding treatment based on immunogenetic/molecular typing.

Lymphomas of the Mediastinum and Their Differential Diagnosis

Lymphoma is the most common malignancy involving the mediastinum but can be challenging to diagnose on small biopsy specimens. This review provides a pattern-based approach to help triage small tissue samples for the diagnosis of mediastinal lymphoid proliferations, with focus on the main primary mediastinal lymphomas. The use of ancillary studies is highlighted, along with considerations to avoid misdiagnosis and scenarios to request additional tissue.

Primary Mediastinal Nodal and Extranodal Non-Hodgkin Lymphomas: Current Concepts, Historical Evolution, and Useful Diagnostic Approach: Part 2

Primary mediastinal non-Hodgkin lymphomas (PM-NHLs) represent ∼5% of all non-Hodgkin lymphomas (NHLs) and comprise lymphomas of B-cell and T-cell origin. PM-NHLs are defined as involvement of mediastinal lymph nodes, thymus, and/or mediastinal organs (heart, lung, pleura, pericardium) by NHL without evidence of systemic disease at presentation. The clinical scenario is variable and depends on the lymphoma subtype. The radiologic presentation is also variable ranging from a mediastinal mass with or without superior vena cava syndrome, a pleural or a cardiac mass associated with effusion, or as an effusion only. The diagnosis of PM-NHLs can only be established by microscopic evaluation, and therefore, general pathologists should be aware of these tumors and familiar with their diagnostic approach. The most common anterior mediastinal NHLs (90% to 95%) are primary mediastinal (PM) large B-cell lymphoma and T-lymphoblastic lymphoma. Thymic marginal zone lymphoma and mediastinal gray zone lymphoma are very rare. The remainder PM-NHLs involving middle or posterior mediastinum include diffuse large B-cell lymphoma (DLBCL) and rare cases of T-cell lymphoma, including anaplastic large cell lymphoma and breast implant-associated anaplastic large cell lymphoma extending to the anterior mediastinum. Primary pleural and cardiac NHLs are mostly DLBCLs. Other rare subtypes of PM-NHLs include DLBCL associated with chronic inflammation/pyothorax-associated lymphoma, fibrin-associated DLBCL (both Epstein-Barr virus positive), and pleural and/or pericardial primary effusion lymphoma (human herpesvirus-8 positive/Epstein-Barr virus positive). We review the historical aspects, epidemiology, clinicoradiologic features, histopathology, immunohistochemistry, differential diagnosis, and relevant cytogenetic and molecular features of the remaining mediastinal B-cell lymphomas, including primary thymic marginal zone lymphoma of the mucosa-associated lymphoid tissue type, other PM small B-cell lymphomas, PM plasmacytoma, and the most relevant PM T-cell lymphomas.

Primary Mediastinal Nodal and Extranodal Non-Hodgkin Lymphomas: Current Concepts, Historical Evolution, and Useful Diagnostic Approach: Part 1

Primary mediastinal non-Hodgkin lymphomas (PM-NHLs) represent ~5% of all NHLs and comprise lymphomas of B-cell and T-cell origin. PM-NHLs are defined as involvement of mediastinal lymph nodes, thymus, and/or mediastinal organs (heart, lung, pleura, pericardium) by NHL without evidence of systemic disease at presentation. The clinical scenario is variable and depends on the lymphoma subtype. The radiologic presentation is also variable ranging from a mediastinal mass with or without superior vena cava syndrome, a pleural or a cardiac mass associated with an effusion, or as an effusion only. The diagnosis of PM-NHLs can only be established by microscopic evaluation, and therefore, general pathologists should be aware of these tumors and familiar with their diagnostic approach. The most common anterior mediastinal NHLs (90% to 95%) are primary mediastinal large B-cell lymphoma and T lymphoblastic lymphoma. Thymic marginal zone lymphoma and mediastinal gray zone lymphoma are very rare. The remainder PM-NHLs involving middle or posterior mediastinum include diffuse large B-cell lymphoma (DLBCL) and rare cases of T-cell lymphoma, including anaplastic large cell lymphoma and breast implant-associated anaplastic large cell lymphoma extending to the anterior mediastinum. Primary pleural and cardiac NHLs are mostly DLBCLs. Other rare subtypes of PM-NHLs include DLBCL associated with chronic inflammation/pyothorax-associated lymphoma, fibrin-associated DLBCL (both EBV), and pleural and/or pericardial primary effusion lymphoma (HHV-8/EBV). We review the historical aspects, epidemiology, clinico-radiologic features, histopathology, immunohistochemistry, differential diagnosis, and relevant cytogenetic and molecular features of PM (thymic) LBCL, PM "nonthymic" DLBCL, BCL, unclassifiable, with features intermediate between DLBCL and classic Hodgkin lymphoma (mediastinal gray zone lymphoma), DLBCL associated with chronic inflammation (pyothorax-associated lymphoma), fibrin-associated DLBCL, and primary effusion lymphoma. This review represents the first part of 2 manuscripts covering PM-NHLs.

Primary Mediastinal Pure Seminomatous Germ Cell Tumor (Germinoma) as a Rare Cause of Precocious Puberty in a 9-Year-Old Patient

Less than 5%-7% of germ cell tumors are extragonadal, with the central nervous system being the most common location in children, followed by retroperitoneum and mediastinum. Only 10% of mediastinal tumors are malignant and one-third of these are pure seminomas (germinomas). We report the case of a 9-year-old boy with development of secondary sexual characteristics. Beta-human chorionic gonadotropin was elevated and a mediastinal mass was found. Final histology showed a pure seminomatous germ cell tumor. To our knowledge, this is the first report of a boy with precocious puberty secondary to a mediastinal germinoma.

Comparison of pediatric and adult lymphomas involving the mediastinum characterized by distinctive clinicopathological and radiological features

Lymphomas involving the mediastinum occur in a wide age range and represent heterogeneous histological subtypes with various clinical symptoms and complex radiological findings. However, studies that describe the clinical and radiological features of different subtypes among Chinese pediatric and adult patients are limited. We analyzed the clinical, radiological and pathological features of 31 pediatric lymphomas involving the mediastinum, and compared them to the features of 21 adult patients. Although several histological subtypes were identified in adults, pediatric patients presented with T-cell lymphoblastic lymphoma/T-cell acute lymphoblastic leukemia (T-LBL/T-ALL) and classical Hodgkin lymphomas (CHL) in 24 and 7 cases, respectively. Compared to adults, pediatric patients were more likely to be male (P = 0.089) and showed a higher incidence of T-LBL/T-ALL (P = 0.001), prevalence of dyspnea (P = 0.001), frequency of stage IV tumors (P = 0.008), and ratio of tumor diameter to maximum transthoracic diameter (P = 0.015). T-LBL/T-ALL patients presented with a higher frequency with stage IV disease (P = 0.000 and P = 0.001), compression of the blood vessels (P = 0.005 and P = 0.017), and pleural effusions (P = 0.001, for both) than CHL and PMBL patients. Compared to adults, pediatric patients with mediastinal lymphomas presented with exclusive histological subtypes of T-LBL/T-ALL and CHL, which showed distinctive characteristics of histological distribution, clinical presentation and radiological assessments.

Mediastinal lesions across the age spectrum: a clinicopathological comparison between pediatric and adult patients

The objective of this study was to identify the differences in histopathological distribution and clinical features of mediastinal lesions (MLs) across the age spectrum in Chinese series of patients and to compare with the available literature. A total of 409 cases of MLs, including 137 pediatric and 272 adult patients from a single institution, was reviewed and categorized into groups according to age. Among the 409 cases, the age showed a bimodal distribution with an increased incidence of MLs among (< 10 year) and (60–< 70 year) age groups. Thymic lesions, neurogenic tumors, and cysts made up 57% of MLs among the 409 cases. A significantly higher frequency was found for neurogenic tumors, germ cell tumors, mesenchymal tumors, and lymphatic lesions, (p < 0.01) for all, in pediatric population compared to adults. On the contrary, frequencies of thymic lesions and metastatic carcinomas were significantly higher in adults compared to pediatric category, (p < 0.01) for both. Overall, 41.6% were asymptomatic, however, pediatric patients showed a significantly higher incidence of cough and fever, (p < 0.01) for both, and dyspnea (p = 0.02), than adults. Whereas adult subset showed a significantly higher incidence of chest pain (p = 0.02), or oppression (p < 0.01), than pediatric counterpart. In conclusion, the age spectrum was the factor that influenced the histopathological distribution and the clinical presentation of MLs in Chinese series of patients. Such differences might be considered in the differential diagnosis and therapeutic approach for adult as well as pediatric patients with MLs. Furthermore, our study was comparable to the literature in terms of MLs frequencies.

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.

Thymomas in childhood: 11 cases from a single institution

AIM

Thymomas are rare in children. Our aim was to review clinical and pathologic characteristics and outcome in children with thymomas.

PATIENTS AND METHODS

Between 1979 and 2011, 11 children with thymomas were diagnosed. Hospital files were reviewed for presenting complaints, clinical, radiologic, and other laboratory data, surgical practices, chemotherapy and radiotherapy outcomes.

RESULTS

Median age was 8 years (range, 1 to 13 y). Male to female ratio was 9/2. Most common initial complaints were dyspnea, cough, chest pain, and fever. Median time from onset of symptoms was 1 month (range, 0.23 to 3 mo). Associated conditions including hyper-IgE syndrome, hypogammaglobulinemia, and systemic lupus erythematosus plus idiopathic thrombocytopenic purpura were present in 3 patients. Chest x-rays and/or thoracic computed tomographies displayed thymic hyperplasia and/or masses in anterior mediastinum accompanied by pleural (n = 2) and pericardial effusions (n = 1), pulmonary metastases (n = 1), and cervical lymph node metastasis (n = 1). Compression or invasion of trachea or vessels was documented in 5 cases. Seven cases underwent initial tumor resection; others experienced open or trucut biopsies. Histopathologically, 5 cases had invasive and 6 had benign thymomas. Benign thymomas did not receive any postoperative treatment; all cases are disease free at a median follow-up of 211 months. Three of 5 cases with invasive thymomas underwent surgery, 4/5 received chemotherapy and external radiotherapy (3600 to 4500 cGy). Two invasive thymomas died of disease. Three cases with invasive thymomas are disease free at a median follow-up of 209 months.

CONCLUSIONS

Benign thymomas have excellent prognosis. For invasive thymomas with or without metastasis, radiotherapy, and chemotherapy offers survival advantage. Complete surgical resection may increase chances for cure.

Mediastinal germ cell tumors in childhood

BACKGROUND

Mediastinal germ cell tumors (GCTs) are rare and usually located in anterior mediastinum. We aimed to review clinical and pathological characteristics of these tumors.

PROCEDURE

Between 1973 and 2011, 24 children with mediastinal GCTs were diagnosed. Hospital files were reviewed for presenting complaints, clinical, radiological and other laboratory data, surgical practices, treatments, and outcomes.

RESULTS

Median age was 4.5 years (0.2-16) (male/female: 10/14). Most common initial complaints were dyspnea, cough, anorexia/fatigue, fever, and chest pain. Primary tumors were located in anterior mediastinum (n = 22), posterior mediastinum (n = 1), and sternum (n = 1). Thirteen of 24 cases had mature teratomas (54.2%); four (16.7%) endodermal sinus tumor (EST); four (16.7%) immature teratomas; and one (4.2%) each of embryonal carcinoma, teratocarcinoma, and malignant teratoma. Mature teratomas underwent only surgical resection and were under follow-up without disease. Four cases with ESTs received chemotherapy and radiotherapy (n = 3), three underwent surgical resections: three died, one was followed for 284 months in remission. All but one immature teratomas were treated with surgery and all were under follow-up without disease. Two patients with embryonal carcinoma and malignant teratoma didn't undergo surgery; both received chemotherapy and radiotherapy but died with disease. The patient with teratocarcinoma was treated with surgery and chemotherapy but died with disease.

CONCLUSIONS

No adjuvant therapy is needed for mature teratomas. Immature teratomas must be under close follow-up for recurrences. Prognosis for mediastinal malignant GCTs was poor. These cases need intensive chemotherapies and effective local control measures as surgery -/+ radiotherapy to ensure long-term survival.

Mediastinal masses in children: experience with 120 cases

Primary mediastinal malignancies are rare tumors and can originate from any mediastinal organ or tissue such as thymic, neurogenic, lymphatic, germinal, or mesenchymal. The authors reviewed all cases of primary pediatric mediastinal masses diagnosed over a 25-year period to determine the pattern of presentation, the histology, and the outcome of the surgical treatment. In this study, 120 primary pediatric mediastinal mass cases diagnosed between 1985 and 2011 are retrospectively evaluated according to their age, sex, symptoms, anatomical location, surgical treatment, and histopathological evaluation. The median age of the patients was 5.8 years. There were 34 benign and 86 malign tumors. Thirty patients were asymptomatic. Common symptoms in the patients were cough, dyspnea, fatigue, fever, abdomen pain, back pain, and neurological symptoms. According to their origins, they were presented as neurogenic tumors (38.3%), lymphomas (18.3%), undifferentiated sarcomas (15%), germ cell tumors (7.5%), and the other tumors (22%) thymic pathologies, lymphangiomas, rhabdomyosarcomas, lipomas, hemangiomas, and Wilms' tumor. Complete resection of the tumor was performed in 86 patients, partial resection of the tumor was the intervention in 11 patients. In 23 patients, biopsy was undertaken. Because of the high incidence of asymptomatic or nonspecific presentation such as the upper airway disease, the presentation of a mediastinal mass in children may be challenging. Neurogenic tumors or lymphomas are indicating surgery, if possible complete resection, for both benign and malignant conditions. Although surgery is the mainstay of therapy for most mediastinal tumors, an experienced multidisciplinary approach is necessary.

Primary intrathoracic low-grade fibromyxoid sarcoma

Low-grade fibromyxoid sarcoma (LGFMS) is a rare neoplasm commonly affecting young adults and typically arising in the somatic soft tissue of the proximal extremities. Its occurrence within the thoracic cavity is exceedingly rare. We report an LGFMS arising from the epicardial surface of the right side of the heart in a 44-year-old woman. Diagnosis was aided by a strikingly characteristic light microscopic appearance of a bland spindle cell sarcoma containing numerous so-called giant collagen rosettes and supported by immunohistology, evidence of FUS translocation by fluorescence in situ hybridization, and electron microscopy demonstrating a fibroblastic phenotype. Aspiration cytology showed a nonspecific bland spindle cell lesion. Review of the literature uncovered 5 previously reported examples of intrathoracic LGFMS. Low-grade fibromyxoid sarcoma is probably an underrecognized intrathoracic neoplasm and should be considered in the differential diagnosis of spindle cell neoplasms of the mediastinum, pleura, heart, and lungs.