Primary mediastinal neoplasms (other than thymoma)

Fine-needle aspiration cytology of mediastinal masses: An institutional experience

Introduction:

Mediastinal masses are uncommon in clinical practice. Fine-needle aspiration cytology (FNAC) is an important and useful investigation and is considered next to imaging in the diagnosis of mediastinal lesions.

Aim:

To analyze the mediastinal masses diagnosed on FNAC.

Materials and Methods:

We retrospectively retrieved twenty-five cases, which underwent FNAC under ultrasound or computed tomography (CT) guidance for mediastinal masses, over a period of 4 years. Histopathological correlations were done in cases wherever available.

Results:

Among twenty-five cases, which were diagnosed through FNAC, eighteen were males and seven were females with age ranging from 6 to 85 years. Ultrasonography (USG)-guided FNAC was performed in three patients, while CT-guided FNAC was performed in twenty-two patients. Out of twenty-five cases, seventeen cases were malignant, six were benign, and two cases were inadequate. FNAC was useful in the diagnosis of 83.3% of cases. Biopsy and/or cell block correlations were available in fourteen cases. In the malignant category, mediastinal invasion by either squamous cell carcinoma or adenocarcinoma constituted the highest number with eight (47%) out of seventeen cases. Among the nonneoplastic conditions, nonspecific inflammation was the most common cause with two cases (8%) out of total cases followed by one case each of tuberculosis, schwannoma, thymoma, and cystic lesion.

Conclusion:

USG or CT-guided FNAC is a safe, minimally invasive, and cost-effective procedure, which can provide a precise diagnosis in the mediastinal masses, and may obviate the need for an invasive surgical approach.

[General Overview of Mediastinal Tumours: Classification, Approaches, Biopsy]

Mediastinal tumours can be a real challenge in terms of diagnostic testing and therapy. One reason for this is that there is a wide range of different tumour types. Even when the tumour is large, many of the affected patients are completely asymptomatic at the time of diagnosis. As a rule, specific types of tumours can be assessed with regard to spatial allocation to a mediastinal compartment. However, if possible, diagnosis should be confirmed via puncture or a biopsy. Various methods are available. Choosing the optimal access route for surgical removal of a mediastinal tumour is an important issue. It must be planned on the basis of the tumour's spatial location, size and extent in imaging. This is the best possible option for low-risk and complete removal of any mediastinal tumour.

Diagnostic evaluation of mediastinal lesions: Analysis of 144 cases

Background:

Mediastinum is a “Pandora's box” with many neoplastic and nonneoplastic lesions. The purpose of this study was to analyze our institutional experience of mediastinal lesions on fine-needle aspiration cytology (FNAC) and/or biopsy.

Materials and Methods:

This study was an analysis of 144 patients who had undergone ultrasound-guided FNAC and/or core biopsy for mediastinal lesions.

Results:

A total of 144 cases of suspected mediastinal masses were seen, and in 139 cases, tissue diagnosis was attempted. Out of 139 cases, 93 cases were neoplastic in nature (67%), 32 were nonneoplastic (23%), and 14 remained inconclusive (10%). Among neoplastic mediastinal lesions, metastatic carcinoma (37.4%) was the most common neoplastic lesion, followed by non-Hodgkin's lymphoma (12.2%), Hodgkin's lymphoma (7.1%), thymic lesions (3.5%), etc. Among nonneoplastic conditions, tuberculosis was the most common lesion (20.1%). An accurate tissue diagnosis was made in 89.9% cases by FNAC or core biopsy of mediastinal lesions in this study. Procedure-related mortality was nil. Complications were mostly minor and included chest pain in 24.5%, small pneumothorax in 13.6% requiring closed tube thoracostomy in 1.4%, and scanty hemoptysis in 9.3% cases.

Conclusion:

Neoplastic mediastinal lesions are more common than nonneoplastic lesions, with metastatic carcinoma being the most common cause followed by tuberculosis. A wide variety of lesions observed in this study stress on the importance of cytohistological diagnosis in all cases of mediastinal lesions for the final diagnosis and management planning. A guided FNAC or core biopsy is still accurate, well tolerated, and devoid of major complications.

Giant Benign Mediastinal Masses Extending into the Pleural Cavity

Introduction  The aim of the study was to evaluate the results of surgery to remove huge mediastinal masses and their pathology. Surgical resection was chosen for accurate diagnosis and treatment of the huge mediastinal masses extending into the pleural cavity. Methods  Records were reviewed for eight patients who had the diagnosis of huge benign mediastinal masses and who underwent operation; details of the patients and operations were recorded. Results  Mean age was 34.5 (range 22 to 44) years, and male-to-female ratio was 2:6. Computed tomography and magnetic resonance imaging (MRI) were used to evaluate the location and extent of the abnormality and to characterize the tissue components of the mass. Most of the tumors were located in the posterior mediastinum. The most frequent presenting symptom was exertional dyspnea. The majority of cases underwent posterolateral thoracotomy, and complete resection was possible in seven patients. Partial resection could only be performed in one. The mean diameter of the resected masses was 15 × 10 cm. Histopathologic examination revealed 3 neurogenic tumors, 2 teratomas, 1 thymolipoma, and 1 ectopic thyroid, and 1 hemangioma. Minor complication was seen in two cases. Conclusion  The presurgical thoracic MRI provided correct diagnosis along with radiologic characterization and topography. Surgery must be the preferred treatment in huge benign mediastinal masses.

Fat-containing lesions of the chest

Although most lesions that occur in the chest have a nonspecific soft-tissue appearance, fat-containing lesions are occasionally encountered at cross-sectional computed tomography (CT) or magnetic resonance imaging. The various fat-containing lesions of the chest include parenchymal and endobronchial lesions such as hamartoma, lipoid pneumonia, and lipoma. Endobronchial hamartoma usually appears at CT as a lesion with a smooth edge, focal collections of fat, or fat collections that alternate with foci of calcification. Mediastinal fat-containing lesions include germ cell neoplasms, thymolipomas, lipomas, and liposarcomas. The most frequent CT manifestation of the germ cell neoplasm teratoma is a heterogeneous mass with soft-tissue, fluid, fat, and calcium attenuation. Cardiac lesions with fat content include lipomatous hypertrophy of the interatrial septum and arrhythmogenic right ventricular dysplasia. Diagnosis of the former is made with CT when a smooth, nonenhancing, well-marginated fat-containing lesion is identified in the interatrial septum. Finally, fat may herniate into the chest at several characteristic locations. When such a lesion is identified, the time required for differential diagnosis is significantly reduced, often allowing a definitive radiologic diagnosis. Sagittal and coronal reformatted images can add valuable information by showing diaphragmatic defects and hernia contents.

Thymic malignancies

Thymomas and thymic carcinomas are unique tumors of the anterior mediastinum. The association of a variety of different paraneoplastic syndromes with such lesions has fascinated physicians and researchers for years. Most recently, it has been demonstrated by numerous authors that thymomas are chemosensitive tumors. Their indolent nature and relative rarity have made evaluation through prospective randomized clinical trials extremely difficult. Further information regarding the molecular nature of these neoplasms and immunologic aspects is needed in future investigation.

Lymphoproliferative disorders presenting as mediastinal neoplasms

Lymphoproliferative disorders may present in any organ of the body. The mediastinum is an uncommon location for presentation of these heterogeneous disorders, but involvement of the mediastinum may be the sole site of disease for several aggressive lymphomas. Both Hodgkin's disease and non-Hodgkin's lymphoma may present in the mediastinum. The most common types of non-Hodgkin's lymphoma involving the mediastinum include lymphoblastic lymphoma and mediastinal large cell lymphoma. These lymphomas most commonly develop in the anterior mediastinum but may be seen in the middle and posterior mediastinum. Symptoms associated with a mediastinal presentation of a lymphoproliferative disorder are often attributable to compression of mediastinal structures (eg, superior vena cava syndrome) or invasion of thoracic structures such as the pericardium or pleura. Although staging can be performed with routine imaging studies, surgical intervention is often required to ensure accurate histologic diagnosis of these lymphomas. Once a diagnosis has been established, therapeutic modalities usually include chemotherapy and/or radiotherapy.

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

PURPOSE

Examine a contemporary series of patients with primary pediatric malignant mediastinal tumors and determine epidemiology, histology, treatment, and survival. Patients and Methods. All malignancies diagnosed between January 1, 1973 and December 31, 1995 were analyzed.

RESULTS

Twenty-two patients, age 18 years or less, with pediatric primary mediastinal malignancies were identified from a database of 110,284 patients with primary malignancies. During the same period, 197 adult patients with primary mediastinal malignancies were identified. Fifty-nine percent of the pediatric patients were male. Median age was 11 years. Lymphoma was present in 55%, neurogenic malignancies in 23%, malignant germ cell tumors in 18%, and sarcoma in 5%. Neurogenic tumors presented in infants and lymphomas and germ cell tumors presented in teens (p = 0.005). In treated children, surgery was used more often in neurogenic tumors and germ cell tumors than in lymphomas (p = 0.002). Five-year survival was 74% for lymphomas, 67% for neurogenic tumors, 25% for germ cell tumors, and 61% overall (p = 0.23). Compared to adults, children had more neurogenic tumors (p < 0.001) and fewer thymomas (p = 0.0499). There were no significant differences in staging or survival between children and adults.

CONCLUSIONS

Pediatric mediastinal malignancies occurred with a frequency of 1/5,013 patients with malignant tumors. Lymphoma, neurogenic tumors, and germ cell tumors predominated. Compared to adults, children had more neurogenic tumors and fewer thymomas. Within the pediatric group, differences were found in age of presentation between histologic groups. These differences between adults and children, and between infants and teens, should be considered when evaluating a patient suspected of having mediastinal malignancy.

Fine-needle aspiration of the mediastinum: a clinical, radiologic, cytologic, and histologic study of 42 cases

Forty-two fine-needle aspirates (FNA) of the mediastinum were reviewed from 1984-1995. The clinical, radiologic, pathologic, and cytologic material was studied. Twenty-five males and 17 females had an age range from 10-72 yr and a mean of 41 yr. Common complaints were chest pain, dyspnea, and cough. Thirty-eight tumors were in the anterior/superior mediastinum. Fifty-seven percent were primary neoplasms (Hodgkin's lymphoma, 7; non-Hodgkin's lymphoma, 6; thymoma, 3; germ-cell tumor, 3; thymic carcinoid and angiosarcoma, 1 each; and malignant not otherwise specified, 3). Twenty-four percent were metastatic tumors (carcinoma, 9; and sarcoma, 1). Twelve percent were benign conditions (granulomatous disease, 2; multinodular goiter, 1; extramedullary hematopoesis, 1; and one thymic cyst). Seven percent were inconclusive. FNA yielded adequate tissue for diagnosis in 83% and a correct diagnosis in 86%. There was one false-negative and no false-positive diagnosis. FNA is a useful tool for accurate tissue diagnosis of mediastinal masses.

Spindle-cell lesions of the mediastinum: diagnosis by fine-needle aspiration biopsy

Spindle cells seen in fine-needle aspiration biopsy (FNAB) of the mediastinal lesions can be a component of a wide variety of benign and malignant conditions. Few of these conditions, however, are described in the FNA cytopathology literature. This review discusses the cytopathologic features, differential diagnoses, and potential pitfalls of a variety of lesions with a significant component of spindle cells encountered in mediastinal FNAB. The cytopathology files from four institutions were searched for cases of mediastinal FNAB containing a spindle-cell component that was a key or predominant cytologic feature of the diagnostic specimen. The cytomorphologic features of these cases were analyzed, and their differential features are discussed. Of 196 mediastinal FNABs, 22 (11%) were lesions with significant spindle-cell component: granulomatous inflammation (four); benign nerve sheath tumor (four); thymic cyst (two); spindle-cell thymoma (two); large-cell non-Hodgkin's lymphoma with sclerosis (two); nodular sclerosing Hodgkin's disease (two); liposarcoma (two); spindle-cell squamous carcinoma possibly arising in a teratoma (one); unspecified high-grade sarcoma (one); spindle-cell malignant melanoma (one); and nonspecific fibrous tissue (one). The cytologic features of each lesion were analyzed as an aid for accurate classification. These findings were correlated with radiologic and clinical information when available. The value of ancillary studies performed on aspirated material in selected cases was also reviewed. FNA of mediastinal lesions with significant spindle-cell morphology represents an infrequent and heterogeneous group of entities that may pose significant diagnostic challenges. This review presents the salient cytopathologic features of various spindle-cell lesions of the mediastinum with particular emphasis on differential diagnosis and pitfalls. The pathologist must use caution when interpreting these lesions and ancillary studies may be of significant value in selected cases.

A review of open biopsy for mediastinal masses

OBJECTIVE

To review the recent experience with biopsied mediastinal lesions in children and to assess the impact of recent advances in imaging and surgical techniques on diagnosis.

METHODOLOGY

The clinical and radiological features of 55 patients who had mediastinal biopsies at The Royal Alexandra Hospital For Children (RAHC) over 15 years were reviewed.

RESULTS

Fifty-five patients presented to RAHC between 1978 and 1993 with lesions of the mediastinum requiring biopsy of that site. Thirty-one of the 55 (56%) lesions were malignant. Neurogenic tumours were the most common (40%). In order of frequency the following lesions were found: neuroblastoma (15), teratoma (eight), non-Hodgkin's lymphoma (NHL; eight), enteric cyst/duplication (five), ganglioneuroma (five), bronchogenic cyst (three), ganglioneuroblastoma (two), lymphangioma (two), abscess (two), Hodgkin's lymphoma (HL; two), oesophageal granuloma (one), Langerhan's cell histiocytosis (one), congenital fibromatosis (one). Eighty-two per cent of neurogenic tumours were located in the posterior mediastinum, while 75% of teratomas and 100% lymphoid tumours were located anteriorly. Symptoms were generally unhelpful in establishing a specific diagnosis and in 27% of cases the lesions were discovered incidentally. Physical signs, such as thoracic inlet obstruction and neurological findings, were helpful clinically in localizing lesions within the mediastinum. Chest radiography enabled lesions to be subdivided within the mediastinum. This localization, in combination with the age at presentation, predicted the tissue diagnosis. Computerized tomography (CT) and magnetic resonance imaging (MRI) further defined the lesion and demonstrated involvement of adjacent structures. Histology, however, was essential to distinguish benign from malignant lesions.

CONCLUSIONS

The clinical presentation of mediastinal masses is often non-specific or incidental. Despite recent advances in imaging technology and biopsy techniques, full histological examination is required to exclude malignancy.

Differential diagnostic considerations and potential pitfalls in fine-needle aspiration biopsies of the mediastinum

The mediastinum is the host for a number of relatively unusual primary neoplasms, as well as a frequent recipient of metastatic tumors. From the perspective of fine-needle aspiration cytomorphology, several distinct patterns are yielded. The polygonal (or epithelial-like) cell pattern may be seen with benign and malignant thymomas, germinomas, embryonal carcinoma, and many metastatic carcinomas. An intimate admixture of small lymphocytes with these epithelial cells may occur in this category. The small cell pattern may be produced by malignant non-Hodgkin's lymphomas, neuroblastoma, carcinoid tumors, and metastatic oat cell carcinoma. Uncommon morphologic forms of thymoma and carcinoid tumors, as well as benign mesenchymal lesions, may yield a picture of a spindle-cell proliferation. In addition to cytomorphology, the cytologist needs to integrate clinical, radiographic, immunocytochemical, and ultrastructural data to formulate a final diagnosis.

A patient presenting for pharyngeal biopsy

A 68-yr-old man presented for pharyngeal biopsy under general anaesthesia. Coincidentally he was found to have a large mediastinal mass. The evaluation of this patient is described. The exact risk of catastrophic airway collapse on induction of anaesthesia in patients with mediastinal masses is controversial but probably small. As there is no test to prevent airway collapse, it is suggested that attempts at biopsy be performed with regional anaesthesia after radiotherapy.