The occurrence of sarcomatous components in primary mediastinal germ cell tumors

Extragonadal germ cell tumors: A clinicopathologic study with emphasis on molecular features, clinical outcomes and associated secondary malignancies

Extragonadal germ cell tumors (EGCTs) are rare, representing <5% of all germ cell tumors (GCTs). Whilst EGCTs share morphological and immunohistochemical features with their gonadal counterparts, they tend to be more aggressive and are frequently associated with secondary somatic malignancies. The aim of our study was to evaluate the clinical, morphological and immunohistochemical features, and to analyze tumors for chromosomal abnormalities of 12p, in addition to any novel genetic alterations, in a series of EGCTs. Seventy-seven EGCTs were included. Anterior mediastinum was the most common anatomic site, followed by central nervous system, retroperitoneum, sacroccygeal area, and neck. Whole genome SNP array identified isochromosome 12p in 26% of tumors. Additional cytogenetic abnormalities included the presence of gain of chr 21 in 37% of tumors. Somatic-type malignancies were identified in 8% of patients. Disease progression (metastasis and/or recurrence) was documented in 8 patients, most of whom died from their relapse. Three patients who died of disease had somatic-type malignancies. Mediastinal seminomas had a significantly better overall survival when compared to mediastinal non-seminomatous GCTs. Our study demonstrates that EGCTs share similar histologic features, but diverse clinical outcomes compared to their gonadal counterparts. Outcomes vary according to anatomic location and histologic subtypes. Our data corroborate that somatic-type malignancies are frequently encountered in mediastinal EGCTs and that their presence portends a poorer prognosis.

Mark Wick contributions to pathology of the mediastinum

Mark Wick made a wide range of contributions to the field of mediastinal pathology. Early papers amplified the spectrum of neuroendocrine carcinomas of the thymus and brought attention to the aggressive nature of this tumor, also highlighting the occurrence of coexisting carcinoid tumor and small cell carcinoma of this organ. The controversial issue of thymoma classification was addressed in several papers and editorial comments, while also reporting a case of metastatic thymoma. A series of thymic carcinomas as well a report on the unusual clear cell variant bear his name as one of the authors. He summarized the topic of mediastinal cyst in a review published in 2005. Sarcomas arising in mediastinal germ cell tumors were also within the purview of his interests, with a publication of series of seven cases. He reviewed the topic of inflammatory myofibroblastic tumor of the heart and added a case to the existing literature. Two books dedicated to different aspect of mediastinal pathology also carry his name in the front cover in association with Drs Taazelar in one and Marchevsky in the other.

Primary germ cell tumours of the mediastinum: A review with emphasis on diagnostic challenges

This article will review current aspects of the histopathological, immunohistochemical and molecular analysis of primary mediastinal germ cell tumours (PMGCTs) as well as their aetiological, epidemiological, clinical and therapeutic features. PMGCTs represent an important differential diagnosis in the spectrum of mediastinal tumours, and their diagnosis is usually made on small tissue samples from core needle biopsies in combination with diagnostic imaging and serum tumour markers. As in lymphomas, a small biopsy is often the only viable tumour sample available from these patients, as they receive chemotherapy prior to eventual surgical resection. Pathologists therefore need to apply an efficient combination of immunohistochemical markers to confirm the diagnosis of a PMGCT and to exclude morphological mimics.

A Case of Mediastinal Carcinosarcoma With Beta-HCG Production and KRAS Mutation

Carcinosarcomas of mediastinum are rare and only few well-documented cases are available in the literature. We report a detailed description of mediastinal carcinosarcoma with unique clinical manifestations and immunohistochemical and molecular profiles. A 44-year-old female with an enlarging anterior mediastinal mass was found to have a positive pregnancy test. Thoracoscopic biopsy revealed that the mass represented a carcinosarcoma with adenocarcinoma and chondrosarcoma components. The tumor focally expressed beta-HCG by immunohistochemistry and had KRAS G12A missense mutation by next generation sequencing. The case documents a rare presentation of carcinosarcoma within the mediastinum with uncommon paraneoplastic syndrome and genetic profile. Awareness of these unusual clinical and pathological manifestations of the tumor will help in reaching correct diagnosis and proper management of such patients.

Malignant Gonadal Germ Cell Tumors (Other Than Pure Germinoma) in Patients With Disorders of Sex Development: A Report of 21 Cases Based Largely on the Collection of Dr Robert E. Scully, Illustrating a High Frequency of Yolk Sac Tumor With Prominent Hepatoid and Glandular Features

We describe 21 nonpure germinomatous gonadal germ cell tumors (9 with a germinoma component), all but 1 associated with gonadoblastoma, in patients with disorders of sex development who ranged from 7 to 36 years old (average, 20 y). Twenty patients were clinically described as phenotypic females with ambiguous genitalia/virilization and primary amenorrhea. The most common documented peripheral karyotype was 46,XY (10/12; 83%). Fifteen of 16 tumors with available clinicopathologic data were unilateral. They ranged from 7 to 30 cm (mean, 15.5 cm) and were solid and cystic with frequent necrosis and hemorrhage. Gonadoblastoma, in its classic (70%), dissecting (5%), or combined (25%) forms, was identified in all but 1. The malignant germ cell tumors were typically mixed except for 5 pure yolk sac tumors and 1 expansile gonadoblastoma with syncytiotrophoblast cells. When admixed, the most common component was yolk sac tumor (n=10), followed by germinoma (n=9), embryonal carcinoma (n=5), choriocarcinoma (n=4), immature teratoma (n=3), and teratoma (n=2). Typical morphologic patterns of yolk sac neoplasia, including reticular/microcystic, solid (including blastema-like), and endodermal sinus (Schiller-Duval bodies), were seen, as well as glandular (n=10) and hepatoid (n=6) differentiation, with cystically dilated glands and diffuse hepatoid morphology in 3 and 2 tumors, respectively. Two yolk sac tumors showed a sarcomatoid pattern. Somatic-type malignancies (alveolar rhabdomyosarcoma and low-grade spindle cell sarcoma, not otherwise specified) were identified in 1 case each. This is the first large series of germ cell tumors other than typical pure germinoma associated with gonadoblastoma. The high frequency of yolk sac tumor with glandular (especially cystic glandular) and hepatoid morphologies is noteworthy, and their presence should prompt further evaluation for an associated gonadoblastoma and possible disorder of sex development.

Vasculogenic Mesenchymal Tumor: A Clinicopathologic and Molecular Study of 55 Cases of a Distinctive Neoplasm Originating From Mediastinal Yolk Sac Tumor and an Occasional Precursor to Angiosarcoma

We report 55 postchemotherapy resections of primary nonseminomatous mediastinal germ cell tumors with prominent vasculogenic features showing the formation of rudimentary to well-developed neoplastic vessels within primitive mesenchyme. These cases represented 25% of a cohort of 221 such specimens. The patients were 19 to 49 years old (mean, 28 y) and 98% had serological evidence of yolk sac tumor. The vasculogenic lesions, felt to represent a neoplastic reiteration of embryonic vasculogenesis in the splanchnic mesoderm of the yolk sac, were further subdivided into teratoma with vasculogenic stroma (n=9), vasculogenic mesenchymal tumor (VMT) (n=42, further classified into low grade [n=24] and high grade [n=18]), and angiosarcoma (n=4). The distinction of teratoma with vasculogenic stroma from VMT was based solely on the greater extent of VMT (exceeding 1 low power [×4 objective] microscopic field), with both categories showing a spectrum of vessels lined by atypical endothelium in a nonendothelial neoplastic stroma that often also generated vascular walls comprised of atypical smooth muscle. The angiosarcomas showed stratification of highly atypical endothelial cells or anastomosing vessels lined by nonstratified but cytologically similar endothelium. Immunohistochemical studies supported the generation of neoplastic vessels from the tumor stroma, most commonly by the development of stromal clefts showing reactivity for podoplanin, CD34, and occasionally ERG, followed by the gradual development from the clefts of thin-walled vessels that later became encircled by stromal cells showing smooth muscle differentiation by immunohistochemistry. Occasionally, round collections of stromal erythrocytes became surrounded by stromal cells to generate blood vessels. Fluorescence in situ hybridization showed chromosome 12p copy number increase in both the endothelial component and stromal component in 8/9 VMT cases and in 1/1 angiosarcoma. On follow-up, no patient with teratoma with vasculogenic stroma had evidence of a subsequent vascular tumor or sarcoma, whereas 8 of the 35 (23%) patients with VMTs (2 low grade and 6 high grade) and meaningful follow-up developed sarcoma (1 angiosarcoma, 2 rhabdomyosarcomas, and 5 not further characterized). The difference between low-grade and high-grade tumors was of borderline significance (P=0.058). Two of the 4 patients with angiosarcoma died of metastatic angiosarcoma, with the other 2 disease-free at 6.8 and 7 years. Compared with the 165 patients with follow-up and no vasculogenic lesions, there was a highly significant (P=4.3×10-5) association of any vasculogenic lesion with sarcomatoid tumors during the clinical course of VMT patients. In addition, 5/46 patients with follow-up and vasculogenic lesions (11%) died of either leukemia or myelodysplastic syndrome compared with 2 of 166 (1%) lacking them (P=0.0012). Three of the 5 patients had identifiable immature hematopoietic cells within their vasculogenic lesions, but 4 other VMT patients with these did not develop leukemia or myelodysplasia. We conclude: (1) vasculogenic lesions are frequent in postchemotherapy resections of primary mediastinal germ cell tumors with yolk sac tumor components; (2) they mostly consist of neoplastic vessels in a stroma that also generates neoplastic vascular walls of smooth muscle; (3) VMTs are associated with an increased incidence of sarcomas, even though most vasculogenic lesions in this context do not meet criteria for angiosarcoma; (4) the presence of vasculogenic lesions in postchemotherapy resections of primary mediastinal germ cell tumors place patients at increased risk for leukemia or myelodysplasia.

Mediastinal Germ Cell Tumor and Acute Megakaryoblastic Leukemia With Co-occurring KRAS Mutation and Complex Cytogenetics

Young males have a unique but rare predilection to develop mediastinal nonseminomatous germ cell tumors (NSGCTs) and concomitant acute megakaryoblastic leukemia (AMKL). Common cytogenetic and molecular abnormalities such as isochromosome 12p and somatic Tumor Protein P53(TP53) and Phosphatase And Tensin Homolog (PTEN) mutations have been reported in the presumed mutual neoplastic clones of origin. We report the case of a 17-year-old male who presented with a mediastinal NSGCT with high-grade sarcomatous transformation and a diagnosis of AMKL approximately 4 months later. Next-generation sequencing revealed identical KRAS Proto-Oncogene, GTPase (KRAS) p.Ala146Thr, TP53 p.Leu257Pro, and PTEN p.Leu181Pro missense mutations at similar variant allele frequencies in both the NSGCT and AMKL samples. Cytogenetic and microarray analyses detected shared copy gains in all chromosomes except chromosomes 9, 13, and Y. Multiple additional clonal chromosomal alterations were detected in the AMKL sample when compared with the NSGCT. This case emphasizes the shared clonal origins of these malignancies and identifies KRAS and other copy number alterations as potential molecular drivers in a subset of these combined diseases.

Pediatric mediastinal germ cell tumors

Mediastinal germ cell tumors (GCTs) are a rare and heterogeneous group of neoplasms. Although histologically resembling their gonadal counterparts, they differ considerably in their clinical characteristics, biological behavior and prognostic outcome. The rarity of mediastinal GCTs has hindered their meaningful analysis, with most studies and clinical trials including them along with other extragonadal GCTs, which has led to a lack of consensus on optimal treatment strategies, and a lull in improvement in patient outcomes. Diagnosis of mediastinal GCT requires a multipronged approach, and encompasses multidisciplinary treatment including chemotherapy followed by surgery, with or without radiotherapy. In view of sustained response rates to current management protocols, the focus needs to be shifted to identifying patients in whom treatment regimens can be downscaled with the aim of decreasing long term morbidity and improving quality of life in low risk patient groups, while improving survival rates in poor risk patient subsets. In this scenario, better understanding of the molecular pathogenesis of these tumors may lead to identification of novel biomarkers and therapeutic targets, as well as improved disease segmentation and risk stratification, thus helping to avoid the toxicity and morbidity associated with current one-fits-all treatment strategies. Multi-institutional collaborations across continents are necessary to generate meaningful data, and are the face of future developments in this arena.

Development of angiosarcoma in a mediastinal non-seminomatous germ cell tumor that exhibited growing teratoma syndrome during chemotherapy

Herein, we report a case of an angiosarcoma in a mediastinal non-seminomatous germ cell tumor that exhibited growing teratoma syndrome during chemotherapy. A 26-year-old man presented with a giant anterior mediastinal mass, which was diagnosed as a non-seminomatous germ cell tumor. The patient was administered three cycles of chemotherapy (bleomycin, etoposide, and cisplatin), but the mass grew despite normalization of tumor markers. Massive bleeding during thoracic surgery resulted in incomplete resection, and the mass was clinically and pathologically diagnosed as growing teratoma syndrome (only mature teratoma). The residual mass continued to grow, and complete resection was subsequently achieved after a detailed analysis of its vascular anatomy using angiography. The final pathological findings revealed angiosarcoma, which indicated a rare somatic type of mediastinal non-seminomatous germ cell tumor.

Hepatic angiosarcomatous transformation of a mediastinal germinal cell tumor: A care case report

RATIONALE

Mediastinal nonseminomatous germ cell tumor (NSGCT) is an uncommon entity. Metastatic hepatic sarcomatous transformation is rare.

PATIENT CONCERNS

We report a 24-year-old man with no previous related medical history presented with chest pain and left arm numbness.

DIAGNOSES

The x-ray showed an anterior mediastinal mass. The chest computed tomography (CT) confirmed the presence of a mildly enhancing mass in the same location, without invasion of any vascular structure. A CT-guided biopsy was performed, revealing a primary mediastinal nonseminomatous germ cell tumor (NSGCT), yolk sac histology, with areas of somatic transformation to malignant nerve sheath tumor. After surgery patient was followed-up with imaging. Two years later a CT scan showed a new hepatic hyper vascular lesion, confirmed by a subsequent magnetic resonance imaging (MRI) and positron emission tomography (PET) scan. A CT-guided biopsy revealed a hepatic metastatic transformation to angiosarcoma of the primitive NSGCT.

INTERVENTIONS

The patient went on to received palliative chemotherapy.

OUTCOMES

The patient is being followed-up regularly at the outpatient department.

LESSONS

Because of the potential of metastatic sarcoma arising from germ cell tumors, these patients should undergo periodical follow-up, with periodical scans. PET\CT scan might have a role in the follow-up of these patients.

Mediastinal pathology and the contributions of Dr. Juan Rosai

Dr. Juan Rosai is one of the most prolific contributors to the literature on mediastinal pathology, and he has added steadily to that body of work over a 50-year period. Rosai has written several landmark articles in this topical area, including articles on thymic epithelial lesions, mediastinal neuroendocrine tumors, mediastinal lymphoma and other hematopoietic lesions, thymolipoma, thymoliposarcoma, mediastinal solitary fibrous tumor, intrathymic langerhans-cell histiocytosis, mediastinal germ cell neoplasms, and multilocular thymic cyst. This review recounts his role as one of the principal figures in the surgical pathology of mediastinal diseases.

Invited Review : The Origin of Mediastinal Germ Cell Tumors in Men

Mediastinal germ-cell tumors in men are generally thought to be primary at this site and to arise from extragonadal germ cells located in the thymus gland. Recent cytoge netic data have cast some doubt on this hypothesis and revived the alternative possibil ity of a testicular origin for these lesions. However, a review of the available evidence suggests that a primary mediastinal origin still remains the most likely explanation. The suggestion is made that the difficulties in identifying normal germ cells in the thymus gland may be due to their evolving into some type of somatic cell such as a myoid cell. Int J Surg Pathol 2(1):73-78, 1994

Rhabdomyosarcoma Originating From an Ovarian Immature Teratoma

We report a rare case with unique histologic findings in the extra-abdominal metastases from an ovarian immature teratoma in a 33-year-old Japanese woman. The primary ovarian tumor was a grade 2 immature teratoma that contained a small aggregate of recognizable rhabdomyoblasts in addition to other immature and mature teratomatous elements. After three courses of chemotherapy, metastatic tumors were identified in the para-aortic area and a right cervical lymph node. Histologically, the para-aortic tumor was predominantly a typical embryonal rhabdomyosarcoma with minor foci of mature teratoma, whereas the cervical tumor consisted only of mature teratomatous elements without any evident immature elements. Int J Surg Pathol 2(3):245-250, 1995

Mesenchymal tumours of the mediastinum--part II

This is the second part of a two-part review on soft tissue tumours which may be encountered in the mediastinum. This review is based on the 2013 WHO classification of soft tissue tumours and the 2015 WHO classification of tumours of the lung, pleura, thymus and heart and provides an updated overview of mesenchymal tumours that have been reported in the mediastinum.

Mesenchymal tumours of the mediastinum--part I

The mediastinum is an anatomically defined space in which organs and major blood vessels reside with surrounding soft tissue elements. The thymus is an important organ in the mediastinum, and many of the masses encountered in the mediastinum are related to this organ. Most neoplasms diagnosed in the mediastinum are epithelial tumours (thymomas and thymic carcinomas), lymphomas or germ cell tumours. In contrast, soft tissue tumours of the mediastinum are rare. In 1963, Pachter and Lattes systematically reviewed soft tissue pathology of the mediastinum, covering the hitherto described [2, 226, 227] In this review, based on the 2013 WHO classification of soft tissue tumours and the 2015 WHO classification of tumours of the lung, pleura, thymus and heart, we provide an updated overview of mesenchymal tumours that may be encountered in the mediastinum.

Postoperative radiotherapy for residual tumor of primary mediastinal carcinoid teratoma

A 36-year-old woman had presented with dry cough for 2 months. Thoracic computed tomography (CT) scan showed a 12 cm × 8 cm ×5 cm mass in the anterior mediastinum. Due to intimately involving the aortic arch, tumor was removed incompletely. Residual tumor remained approximate 2 cm × 3 cm × 4 cm. Histologic diagnosis was a mature cystic teratoma containing a carcinoid. Subsequently, radiotherapy (RT) was administrated on residual tumor for a total dose of 50 Gy at 2 Gy/d fraction in 25 fractions. At 2-year follow-up, the patient had stable disease. In conclusion, adjuvant radiotherapy with 50 Gy is an effective approach for residual tumor of mediastinal carcinoid teratoma.

Anterior Mediastinal Mass Biopsy and Resection

The perioperative management of the patient with an anterior mediastinal mass (AMM) is viewed as one of the more challenging anesthetic endeavors. Diligent preoperative planning is essential and often involves imaging studies using multiple modalities, pulmonary function assessment, and minimally invasive biopsy for tissue diagnosis prior to arriving in the operating room. Anesthetic induction, often without major risks in most patients, can be catastrophic in AMM patients, with possible complications that include complete airway obstruction and cardiovascular collapse. The authors present the case of a biopsy via anterior mediastinotomy under monitored anesthesia care (MAC)/sedation in a 39-year-old man, who presented with a large AMM causing significant right heart compression without tracheobronchial involvement. This procedure was followed by definitive mass resection approximately 6 weeks later. This review will explore the following: (1) the use of MAC/sedation for AMM biopsy, (2) methods of safely securing the airway in patients undergoing definitive mass resection via median sternotomy, (3) current opinions regarding the need for preoperative pulmonary function testing in these patients, (4) current opinions regarding the need for and timing of cardiopulmonary bypass in these cases, (5) the use of intraoperative transesophageal echocardiography during resection, and (6) the characteristics of mediastinal germ-cell tumors with sarcomatous conversion. Though multiple anesthetic methods have been proposed for the management of patients undergoing tissue biopsy and resection of an AMM, this case report presents 2 successful anesthetic options for 2 distinct surgical procedures. In every instance, the anesthetic management options must be tailored to the unique physiological needs of the patient presenting for surgery.

Typical carcinoid arising in mature teratoma of anterior mediastinum

Teratoma is the second most common mediastinal neoplasm, but malignant transformation in mature teratomas is uncommon at both gonadal and extragonadal sites. A 35-year-old woman presented with an anterior mediastinal mass. Computed tomography suggested a teratoma. Meticulous pathological examination helped in detecting a neuroendocrine neoplasm (carcinoid) within the mature teratoma. Malignant transformation in a teratoma is difficult to diagnose on clinical and radiological assessment; histopathology is essential to detect the malignant nature of these neoplasms.

Ovarian germ cell tumors with rhabdomyosarcomatous components and later development of growing teratoma syndrome: a case report

Introduction

Development of a sarcomatous component in a germ cell tumor is an uncommon phenomenon. Most cases reported have a grim prognosis. Growing teratoma syndrome is also an uncommon phenomenon and occurs in approximately 2% to 7% of non seminomatous germ cell tumors and should be treated surgically.

Case presentation

We report the case of a 12-year-old Asian girl with an ovarian mixed germ cell tumor containing a rhabdomyosarcomatous component. She was treated with a germ cell tumor chemotherapy regimen and rhabdomyosarcoma-specific chemotherapy. Towards the end of her treatment, she developed a retroperitoneal mass that was increasing in size. It was completely resected, revealing a mature teratoma, consistent with growing teratoma syndrome. She is still in complete remission approximately three years after presentation.

Conclusion

The presence of rhabdomyosarcoma in a germ cell tumor should be treated by a combined chemotherapy regimen (for germ cell tumor and rhabdomyosarcoma). In addition, development of a mass during or after therapy with normal serum markers should raise the possibility of growing teratoma syndrome that should be treated surgically.

A unique case of a sarcoma arising in a testicular non-seminomatous mixed germ cell tumour with a predominant yolk sac component

We present a unique case of a sarcoma arising in a testicular non-seminomatous mixed germ cell tumour with a predominant yolk sac tumour (YST) component. This is the first case reported in which a sarcoma is linked to YST of the testis in a patient not having undergone prior chemotherapy. This finding confirms the ability of YST to contain sarcoma; it underlies its importance for urologists, oncologists and pathologists to be aware of this phenomenon and to modify treatment strategies appropriately.

Papillary renal cell-like carcinoma in a retroperitoneal teratoma

We report a case of somatic type malignancy with papillary renal cell carcinoma differentiation arising in a retroperitoneal mixed germ cell tumor. The patient was a 36-year-old man with a synchronous mediastinal teratoma. The somatic type malignancy in the retroperitoneal tumor was composed of papillary structures covered by atypical epithelial cells with eosinophilic cytoplasm, prominent nucleoli and pseudostratified nuclei. Papillary cores contained numerous aggregates of foamy macrophages, typical of type I papillary renal cell carcinomas. The immunohistochemical profile was consistent with papillary renal cell carcinoma, including positive reactions for cytokeratin 7 and alpha-methyl acyl CoA racemase. There was no somatic type malignancy component in the synchronous mediastinal teratoma. Both the retroperitoneal and the mediastinal tumor showed gains of 12p and chromosome 17 material. There was no c-MET mutation in the somatic type malignancy. To our knowledge, this is the first report of a somatic type malignancy with features of papillary renal cell carcinoma arising in a germ cell tumor. It is important not to confuse such a retroperitoneal tumor with a conventional papillary renal cell carcinoma, because presence of other malignant histologies within the germ cell tumor may warrant different treatment. In such cases, the presence of isochromosome 12p can be helpful to the diagnosis.

Mediastinal germ cell tumors with an angiosarcomatous component: a report of 12 cases

The development of an angiosarcomatous component in germ cell tumors is rare. Here we studied 12 cases of mediastinal germ cell tumors with an angiosarcomatous component. All patients were men with a mean age of 34 years (range, 24-49 years). No patient had a documented testicular germ cell tumor. The mean size of mediastinal tumors was 12.9 cm (range, 5.5-16.0 cm). Grossly, the tumors were cystic with variegated hemorrhagic, mucinous, and fleshy solid areas. Microscopically, all tumors were composed of germ cell tumor. The most common germ cell tumor component was teratoma (n = 10); and other germ cell tumor components included seminoma (n = 3), yolk sac tumor (n = 3), embryonal carcinoma (n = 2), and choriocarcinoma (n = 1). The angiosarcomatous component was present in primary mediastinal tumors (n = 6), metastasis (n = 3), or both primary mediastinal tumor and metastasis (n = 3). The angiosarcomatous component accounted for an average of 30% (range, 5%-95%) of the primary mediastinal tumor. In addition, other non-germ cell components, including rhabdomyosarcoma (n = 3), leiomyosarcoma (n = 1), and poorly differentiated carcinoma (n = 1), were also present in the tumors. Of the 10 patients with follow-up available, all patients developed metastasis (n = 8) or local recurrence (n = 2); 7 died of disease at a mean of 33 months (range, 21-75 months), and 3 patients were alive at a mean of 75 months (range, 5-120 months). Our findings suggest that the presence of an angiosarcomatous component in mediastinal germ cell tumor, even in a small amount, is associated with a poor clinical outcome.

Sacrococygeal teratoma with sarcomatous differentiation in a child

Most of the extragonadal teratomas are located in the sacrococygeal region. Teratoma with malignant sarcomatous differentiation is a rare form of germ cell tumor. The authors describe a 5-year-old-girl with sacrococygeal teratoma in which sarcomatous elements were observed. The patient was treated with complete surgical excision and adjuvant chemotherapy according to sarcoma protocols.

Germ Cell Tumors With Sarcomatous Components

The clinicopathologic features of 46 patients with germ cell tumors with sarcomatous components (GCTSC) involving either the primary site or their metastases were studied. There were 43 men and 3 women aged 17 to 74 years. Twenty-three tumors arose in the mediastinum, 2 in the retroperitoneum, and 21 in the gonads. The germ cell component consisted of pure mature or immature teratoma (23 cases), teratoma mixed with other seminomatous or nonseminomatous components (17), pure seminoma (2), intratubular germ cell neoplasia (1), and yolk sac tumor (1). The SC included embryonal rhabdomyosarcoma (29), angiosarcoma (6), leiomyosarcoma (4), undifferentiated sarcoma (3), myxoid liposarcoma (1), malignant peripheral nerve sheath tumor (1), malignant "triton" tumor (1), and epithelioid hemangioendothelioma (1). Immunohistochemical studies were carried out in 34 cases with appropriate results supporting the diagnoses. Metastases containing both GCT and SC were observed in 6 cases, metastases of SC alone in 4, and metastases containing only GCT elements in 3. All patients were treated by cisplatinum-based chemotherapy plus other agents followed by surgery. Clinical follow-up was available in 40 patients (1 to 96 mo; mean=24 mo). Thirty-two of 40 patients either died of tumor (25/40; 62.5%) or were alive with advanced, progressive disease (7/40; 17.5%), and only 8/40 (20%) were alive and free of disease between 5 to 40 months (mean=18 mo). Comparison of these patients with an age-matched and stage-matched control group of patients with GCT without SC showed statistically significant differences in survival between the 2 cohorts (P <or=0.001). On the basis of our findings, the presence of SC appears to represent a poor prognostic sign for GCTs of gonadal and extragonadal origin.

Extragonadal germ cell tumors: a review with emphasis on pathologic features, clinical prognostic variables, and differential diagnostic considerations

Extragonadal germ cell tumors (GCTs) are relatively uncommon, but represent 1% to 5% of all GCTs. Their morphology varies widely and includes mature teratoma, immature teratoma, seminoma, yolk sac tumor, embryonal carcinoma, choriocarcinoma, and mixed GCTs. Noncentral nervous system extragonadal GCTs are found in a variety of anatomic locations, but most commonly affect the mediastinum and sacrococcygeal region. Predicting behavior in these tumors can be confusing because it is based on a combination of varying factors including patient age, histologic subtype, anatomic site, and clinical stage. This review attempts to dissect these issues by separating the discussion into 3 age groups: neonatal (congenital), children (prepubertal), and adult (postpubertal). Within each individual age group, we cover the significance of anatomic site, morphology, and staging parameters. In addition, we discuss the spectrum of associated secondary malignancies and their impact on patient outcome. Finally, we provide a detailed survey of differential diagnostic considerations grouped by anatomic site.

Malignant ganglioneuroma arising from mediastinal mixed germ cell tumor

Mixed germ cell tumors with non-germ cell malignant components rarely occur in the anterior mediastinum. We report a case of a 34-year-old man who presented with an anterior mediastinum mass. Mixed germ cell tumor was initially diagnosed based on the pathologic findings of germinoma on thoracoscopic biopsy and clinical findings of elevated serum alpha-fetoprotein and beta-human chorionic gonadotropin. The patient received preoperative chemotherapy and subsequent complete resection of the residual tumor. Pathologic examination of the excised specimen showed predominantly malignant ganglioneuroma and small residual foci of teratoma. To our knowledge, this is the first reported case of a malignant ganglioneuroma arising from mediastinal mixed germ cell tumor.

"Cutaneous-type" angiosarcoma arising in a mature cystic teratoma of the ovary

Benign and malignant somatic tumours arising in mature cystic teratomas of the ovary are a rare but recognised phenomenon. Squamous cell carcinoma is the most common somatic malignancy arising in ovarian teratomas, although many other types of tumour have been described. An angiosarcoma with "cutaneous" type typical features arising in a dermoid cyst of the ovary is reported. Vascular tumours have only rarely been described as secondary somatic tumours in ovarian teratomas. The diagnostic features and complications of such tumours are described.

Mediastinal germ cell tumors

Germ Cell Tumors (GCT) represent an important group of mediastinal tumors. Because of genetic characteristics and behavior have been divided in prepubertal and postpubertal tumors, and their origin remains controversial. The genetic changes are diverse, but the most frequent is i (12p), and can be associated to gonadal disgenesis. Histological classification is similiar to that of gonadal tumors and all histological types have been described in the mediastinum. Teratomas may undergo malignant transformation with the emergence of somatic tumors such as haematological malignancies, sarcomas, carcinomas and neurogenic tumors, and such transformation may occur in the primary site or in the metastases. Prognostic factors in mediastinal germ cell tumors include: age of the patient, histological type, distant metastases, stage, status of resection, level of serum tumor markers and proliferation markers. Immunohistochemistry is especially useful when the primary GCT is occult, to separate types of immature GCT, and to determine the lineage of malignant transformation which may be important to design treatment strategies.

Thymic carcinosarcoma consisting of squamous cell carcinomatous and embryonal rhabdomyosarcomatous components. Report of a case and review of the literature

A case of thymic carcinosarcoma in an 83-year-old Japanese man is presented. He died of superior vena cava syndrome caused by a rapidly enlarged anterior mediastinum tumor eight months after initial symptoms. Autopsy revealed a 16 x 12 x 25 cm-sized, tan yellow, whitish tumor with a multinodular and microcystic appearance located in the left anterior mediastinum, which involved the residual thymus. The tumor had directly invaded the left pleura, and had metastasized to the right lung and spleen. Histologic examinations of the primary tumor showed a sarcomatous component consisting of racquet- or spindle-shaped cells with cross striations, and small nests of atypical squamous cells scattered throughout the tumor; neither transition between the two components nor intermediate cells with both epithelial and mesenchymal features was seen. Electron microscopic and immunohistochemical examinations confirmed the rhabdomyomatous differentiation of the sarcomatoid component. To our knowledge, there have been only two reported cases showing histologic features similar to the present tumor. For the histogenesis of thymic carcinosarcoma, we propose two hypotheses. The first is that sarcomatous cells are derived from carcinomatous cells by tumoral metaplasia. Secondly, that this type of tumor originates from thymic primitive cells with multidirectional differentiation potential. In accordance with the latter, we consider that the present tumor originated from thymic primitive cells. Thymic carcinosarcoma is a highly malignant tumor, and most patients die within a year. Appropriate therapies must be developed.

Intensive chemotherapy and radical resections for primary nonseminomatous mediastinal germ cell tumors

BACKGROUND

Primary nonseminomatous germ cell tumors of the mediastinum (PNSGM), unlike malignancies of gonadal origin, have a poor prognosis. We report a single institutional experience over a 5-year period of PNSGM treated with intensive chemotherapy, followed by radical operation in those who responded to this neoadjuvant regimen.

METHODS

From 1993 to 1998, 20 patients were referred for the management of PNSGM. All were male, with a median age of 30.5 years (range 18 to 48). Eighteen of 20 (90%) presented with symptoms. Most tumors were large, with a median diameter of 10 cm (range 3 to 20 cm). Thirteen patients (65%) had metastatic disease at the time of presentation. Eleven patients had received no prior treatment (initial group) and 9 were referred for salvage therapy after progression of their tumors, following treatment at other facilities (salvage group). All had elevated serum tumor markers (beta hCG and alpha-fetoprotein). Preoperative chemotherapy included alternating cycles of combinations of 3 or more drugs, including cisplatin, bleomycin, etoposide, vincristine, methotrexate, actinomycin, cyclophosphamide, and doxorubicin. An average of 10 cycles of chemotherapy was given to each patient in the initial group, and six to those in the salvage group. Five patients (25%) developed transient renal insufficiency, and 35% developed pulmonary infiltrates related to bleomycin. There were 3 chemotherapy related deaths.

RESULTS

After chemotherapy, 11 patients underwent operation, with 10 complete resections of the residual mediastinal tumors. There were no perioperative deaths. The 2-year survival in the initial group is 72%, and 42% for the salvage group.

CONCLUSIONS

An aggressive, multidisciplinary approach of alternating cycles of chemotherapy, followed by complete surgical resection of all remaining disease in patients whose markers normalize, can be associated with prolonged survival in patients with PNSGM.

Small cell neuroendocrine carcinoma with skeletal muscle differentiation: report of three cases

Three cases of neuroendocrine carcinoma showing skeletal muscle differentiation are presented. The tumors were located in the skin and subcutaneous tissue, the urinary bladder, and the nasal cavity respectively, and were composed by two cell types admixed intimately with each other. One cell type had features identical to those seen in conventional small cell neuroendocrine carcinoma, including scanty cytoplasm, round nuclei with fine granular chromatin, immunohistochemical reactivity for neuron-specific enolase, chromogranin and cytokeratins, and electron-dense granules on ultrastructural examination. The second cell type was either plasmacytoid or elongated and straplike, with abundant eosinophilic cytoplasm and irregular nuclei with prominent nucleoli. These cells showed immunohistochemical positivity for desmin, sarcomeric actin, myoglobin, and myogenin. They also exhibited ultrastructural evidence of rhabdomyoblastic differentiation in the form of contractile filaments with abortive Z-band formation. An origin from a cell capable of dual differentiation toward neuroendocrine and rhabdomyoblastic elements is postulated for these tumors.

Mediastinal non-seminomatous germ cell tumours: their association with non-germ cell malignancies

Mediastinal non-seminomatous germ cell tumors are unique tumors in that they are associated with both sarcomatous and hematologic neoplasms. This paper relates our experience at Indiana University with these tumors, and discusses the possible mechanisms of their occurrence, especially with respect to the hematologic neoplasms.

Primary angiosarcoma of the ovary: a case report and review of the literature

INTRODUCTION

Gynecological sarcomas are rare and have a poor prognosis. Uterine sarcomas are most common accounting for 4% of all uterine tumors. Ovarian sarcomas are less frequent and are usually carcinosarcomas.

CASE REPORT

A previously healthy 40-year-old G2P2 presented for evaluation of 72 h of right upper quadrant pain and shortness of breath. A malignant right pleural effusion, ascites, and adnexal mass were found. Surgical staging and suboptimal debulking revealed pure angiosarcoma of the ovary Stage IV.

DISCUSSION

There are 12 cases of ovarian angiosarcoma reported in the literature. Ten of these cases presented in advanced stages with survivals of 2-30 months. Various chemotherapy regimens have been tried on these tumors including the most recent recommendation of MAID (mesna, doxorubicin, ifosfamide, and dacarbazine) and prognosis remains poor. Our patient underwent elective right pleurodesis via video-assisted thorascopic surgery under local anesthesia for an early recurrent right pleural effusion and subsequently began MAID chemotherapy.

Occurrence of malignant non-germ cell components in primary mediastinal germ cell tumours

METHODS

Thirty-five patients with primary mediastinal germ cell tumours (PMGCT) underwent primary thoracotomy in a 30-year period (1965-1994). Of the 35 patients, 12 had benign teratomas, five pure seminomas and 18 non-seminomatous germ cell tumours.

RESULTS

Out of 18 non-seminomatous germ cell tumours, 14 comprised more than one malignant component. In two cases malignant teratomas had an additional malignant non-germ cell component: one a mixed sarcomatous component and the other a neuroendocrinal component. There were different methods of treatment between 1965 and 1994. All but one of patients with seminomas survived for 5 years. Among 18 patients with malignant PMGCT, all but two died within 5 years (mean survival rate was 15 months).

CONCLUSIONS

When planning treatment of patients with malignant PMGCT we have to take into account the fact that malignant non-germ-cell components may occur. In this circumstances, surgical resection after initial chemotherapy is recommended.

Yolk sac tumors of the mediastinum with prominent spindle cell features: a clinicopathologic study of three cases

Three cases of primary mediastinal yolk sac tumors with prominent spindle cell features are presented. The patients were three men 24-34 years of age (mean 29). Clinically, two patients presented with symptoms of chest pain and cough; no clinical information was provided for the third patient. Grossly, the tumors were described as large mediastinal masses, with a hemorrhagic and necrotic cut surface. Histologically, the tumors were characterized by a predominantly atypical spindle cell proliferation admixed with areas that showed focally the characteristic reticular growth pattern of yolk sac tumors, with the presence of Schiller-Duval bodies and intra- and extracellular hyaline globules. Immunohistochemical studies performed in one case showed positive staining for keratin and alpha-fetoprotein in both the spindle cell and reticular components of the tumor. Follow-up information was obtained in two patients; they both died of tumor with metastases to the lungs 1 year after initial diagnosis. The present cases expand the spectrum of histopathologic growth patterns that may be observed in yolk sac tumors of the mediastinum and stress the issue of careful sampling and evaluation of mediastinal neoplasms for arriving at the correct diagnosis.

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.

Primary mediastinal choriocarcinomas: a clinicopathologic and immunohistochemical study of eight cases

Primary choriocarcinoma of the anterior mediastinum is by far the rarest and most controversial form of extragonadal germ cell tumor. A clinicopathologic study of eight primary mediastinal neoplasms bearing the histopathologic and immunohistochemical features of choriocarcinoma is presented. The patients were all men between the ages of 21 and 63 years (mean, 42 years). Clinical symptoms included shortness of breath, chest pain, cough, and superior vena cava syndrome; one patient also had gynecomastia. All patients presented with large anterior mediastinal masses on chest radiographs that measured an average of 10 cm in greatest diameter. Grossly, the tumors were described as large, soft, extensively hemorrhagic, and with foci of necrosis. Histologically, they were characterized by a dual cell population composed of cytotrophoblastic cells with uniform, round nuclei, clear cytoplasm, and prominent nucleoli admixed with large, multinucleated syncytiotrophoblastic cells with bizarre nuclei, prominent nucleoli, and abundant eosinophilic cytoplasm. Immunohistochemically, the tumors were notable for strong keratin and beta-human chorionic gonadotropin (HCG) positivity. Seven patients presented at the time of diagnosis with thoracic and extrathoracic (liver, adrenal, kidney, and spleen) metastases. In one case, the tumor was entirely confined to the mediastinum. All patients died over a period of 1 to 2 months. Complete autopsies were performed in all cases; none of the patients showed evidence of a testicular tumor or scar after thorough examination of the testes on serial sectioning. The present cases demonstrate the widespread distribution of germ cells in the human body and lend further support to the existence of primary extragonadal choriocarcinoma arising in the thymic region.

Primary immature mediastinal teratoma in adulthood

Primary immature mediastinal teratoma is very rare. The prognosis of this tumour observed in the late teens or adulthood was thought to be very poor. However, recent advances in chemotherapy have improved the prognosis. Eleven patients > 15 years of age with immature mediastinal teratoma (two of our patients and nine from the literature) were reviewed. These patients were classified into survivor and non-survivor groups, and the characteristics in each group were evaluated. In the survivor group, the tumour was completely resected in all patients. In addition, patients showing a high level of alpha-fetoprotein were treated by pre-operative chemotherapy, and those who were pre-operatively negative for tumour markers were treated by post-operative chemotherapy and survived for a long period. All patients in whom the tumour was resected incompletely, or where no chemotherapy was performed, were included in the non-survivor group. In patients > 15 years of age with immature mediastinal teratoma, complete surgical resection of the tumour is indispensable. When complete resection is combined with chemotherapy, long survival can be expected. Conversely, unless both treatment methods are performed, the outcome is very poor.

Goblet cell carcinoid arising in a mature teratoma of the mediastinum

Goblet cell carcinoid (GCC) is a rare but distinctive neoplasm with features of both adenocarcinoma and carcinoid tumor. Most cases described in the literature have occurred in the appendix. An additional well-defined location is the ovary, and these tumors have been associated with a mature teratoma of the ovary. GCC arising within a mature teratoma of the mediastinum has not been described in the English-language literature. We report a case of this previously undescribed entity and provide a review of the literature on mediastinal teratomas with malignant transformation. The histologic findings included uniform, smooth-bordered glandular nests lined by goblet cells and admixed endocrine and Paneth cells. Occasional tubular glands were present, as were transitional type glands with both goblet cell and tubular features. Cytologic atypia was minimal, and mitotic activity was rare. Immunohistochemical studies showed positive staining of GCC tumor cells with chromogranin, cytokeratin, neuron-specific enolase, serotonin (focal), and Leu-7 (focal). The GCC component was entirely contained within the mature teratoma.

Primary intratesticular sarcoma. Immunohistochemical ultrastructural and DNA flow cytometric study of three cases with a review of the literature

BACKGROUND

Fourteen cases of testicular sarcoma have been reported in the contemporary era. These included 7 cases of rhabdomyosarcoma, 2 spindle cell sarcoma, 2 osteosarcoma, 1 leiomyosarcoma, 1 fibrosarcoma, and 1 chondrosarcoma coma.

METHODS

In this report, immunohistochemical stains, electron microscopy, and DNA flow cytometric analysis were performed on primary testicular sarcomas from three patients.

RESULTS

The patients were age 47, 40, and 33 years. Each presented initially with a testicular mass. The tumors measured 4.8, 4.0, and 4.0 cm in greatest dimension. There was no associated germ cell elements nor elevated alpha-fetoprotein or beta-human chorionic gonadotropin. Case 1 was positive for actin, vimentin, and alpha-1-chymotrypsin. Case 2 was positive for vimentin but not desmin. Case 3 was positive for desmin and S-100. Smooth muscle differentiation was identified by electron microscopy. Flow cytometric analysis revealed DNA aneuploidy in all cases: 1.27, 1.29, and 1.71. The 3 patients were alive and well without recurrent disease at 7, 6, and 4 years after diagnosis. Inguinal orchiectomy was the initial treatment in all 17 patients, there was 1 death from metastatic disease and 2 patients with distant metastases.

CONCLUSION

Primary testicular sarcoma is a rare indolent tumor with potential for distant metastases. Two cases of primary testicular leiomyosarcoma and one of unclassified sarcoma of the testis are reported.

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.