Neuroendocrine carcinoma in a mediastinal teratoma as a rare variant of somatic-type malignancy

En bloc resection of an extremely giant mediastinal immature teratoma with somatic-type malignancy: A case report with a brief review of the literature

Primary mediastinum immature teratoma with somatic-type malignant transformation (SM) is extremely rare, and the clinical prognosis is poor. Immature teratoma with SM is difficult to eradicate by chemotherapy due to poor sensitivity; therefore, surgical resection is recommended whenever possible because it may offer better survival.

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.

Mediastinal high-grade vasculogenic mesenchymal tumour with seminoma: a case report and literature review

Germ cell tumours with somatic-type solid malignancy (GCT-STM) are a rare disease of the mediastinum. Recently, a cohort of vasculogenic mesenchymal tumour (VMT)-nonseminoma cases with different prognoses were recognized and reported. Here, we report a case of mediastinal high-grade VMT with a seminoma. A 16-year-old male had a fever, chest tightness and fatigue. Chest CT showed a 7.5 cm×5.3 cm solid mass in the right anterior mediastinum. The serum levels of alpha-fetoprotein (AFP), beta-human chorionic gonadotropin (β-HCG) and carcinoembryonic antigen (CEA) were within the normal range. Tumorectomy was performed. The tumour was irregular, and no capsule was found. The cut surface was greyish white and greyish brown with medium consistency. There were foci of bleeding and necrosis. Microscopic histology showed prominent vascular proliferation, which was lined by mildly atypical endothelial cells in a cellular stroma with significant cytologic atypia. The vascular spectrum varied from crevice-like or antler-like thin- to thick-walled vessels. Beyond the tumour area, inside the remnant thymus tissues, there were small clusters of polygonal tumour cells with clear cytoplasm, distinct cell membranes, and round to polygonal nuclei with prominent nucleoli that were positive for Oct4, PLAP, SALL4 and CD117. The patient did not receive any treatments pre- or postoperation, and his condition was stable without progression after 14 months of follow-up evaluation. Here, we added a new entity of GCT-STM of the mediastinum composed of VMT and seminoma. A better understanding of the pathological features of GCT-VMT could help pathologists improve their awareness of these rare diseases.

Mediastinal Germ Cell Tumors: A Review and Update on Pathologic, Clinical, and Molecular Features

Mediastinal germ cell tumors (MGCTs) are the most common extragonadal germ cell tumors (GCTs) and most often arise in the anterior mediastinum with a male predilection. MGCTs also have a predilection for patients with Klinefelter syndrome and possibly other genetic conditions. MGCTs, as GCTs at other extragonadal sites, are thought to arise from germ cells improperly retained during migration along the midline during embryogenesis. Similar to their counterparts in the testes, MGCTs are classified into seminomatous and nonseminomatous GCTs. Seminomatous MGCT represents pure seminoma, whereas nonseminomatous MGCTs encompass pure yolk sac tumors, embryonal carcinoma, choriocarcinoma, mature or immature teratoma, and mixed GCTs with any combination of GCT types, including seminoma. Somatic-type or hematologic malignancies can also occur in association with a primary MGCT. MGCTs share molecular findings with GCTs at other sites, most commonly the presence of chromosome 12p gains and isochromosome i(12p). Treatment includes neoadjuvant chemotherapy followed by surgical resection of residual tumor, with the exception of benign teratomas, which require only surgical resection without chemotherapy. In this review, we highlight and provide an update on pathologic, clinical, and molecular features of MGCTs. Immunohistochemical profiles of each tumor type, as well as differential diagnostic considerations, are discussed.

Neuroendocrine tumors of the thymus and mediastinum

Neuroendocrine tumors of the thymus (tNET) and mediastinum are very rare neoplasms with scarce available data. All subtypes [typical and atypical carcinoid tumors (TC and AC), large cell neuroendocrine and small cell carcinoma (SCC)] observed elsewhere in the body occur also in the mediastinum and show only few if any organ-specific morphological differences. Although all available data suggest that the broad principles that govern the biology (and hence) the classification of these tumors in general apply also to tNET, there are a few noteworthy peculiarities related e.g., to risk factors, relative frequency and also to molecular genetic features. In this review, we will briefly summarize current knowledge on tNET with a special emphasis on shared and private features in comparison e.g., with pulmonary NET, which have traditionally been regarded the next closely related NET group.

Primary atypical carcinoid tumor of the mediastinum: a very rare finding

Primary neuroendocrine tumors (NETs) of the mediastinum are very rare. Prognosis is usually poor despite treatment options. We present the case of a primary atypical carcinoid tumor of the mediastinum successfully treated by multimodal approach. A 50-year-old man presented for asthenia, dyspnea, and substernal sense of weight for two weeks. A chest-CT scan revealed a tumor mass of 107×55×95 mm³ localized in the anterosuperior mediastinum compressing both brachiocephalic veins, the superior vena cava, the pericardium, and lungs. A FDG-PET demonstrated high FDG uptake only in the mediastinal mass; no metastases were seen. CT-guided needle biopsy revealed a NET; cells were immunoreactive for synaptophysin; Ki67 was 20%. After neoadjuvant chemotherapy, the chest CT-scan showed a significant reduction of the tumor. A surgical excision was proposed. The tumor was radically removed along with a partial resection of the vena cava and reconstruction with a bovine pericardium patch. The patient underwent 25 sessions of adjuvant radiotherapy. Microscopically the tumor showed clusters of medium-sized cells, eosinophilic cytoplasm with nuclear pleomorphism and small nucleoli, arranged in trabeculae, nests and lobules. No thymic tissue was found. Immunohistochemically the tumor cells were positive for CD117, synaptophysin, chromogranin, CD56, cytokeratin pool, epithelial membrane antigen (EMA), and negative for thyroid transcription factor-1 (TTF1), leukocyte common antigen (LCA), fibroblast-activation protein (FAP), prostate-specific antigen (PSA), P63, CD5 and CD99. Mitoses were found to be 8/10 HPF. The Ki67 was 10%. A diagnosis of primary NET of the mediastinum, intermediate grade (G2), atypical carcinoid according to WHO 2015, was formulated. Even in case of primary NE mediastinal tumor, a multimodal approach could lead to long-term survival.

[Mediastinal germ cell tumors]

The mediastinum is among the most frequent anatomic region in which germ cell tumors (GCT) arise, second only to the gonads. Mediastinal GCT (mGCT) account for 16 % of all mediastinal neoplasms. Although the morphology and (according to all available data) the molecular genetics of mediastinal and gonadal GCT are identical, a number of unique aspects exist. There is a highly relevant bi-modal age distribution. In pre-pubertal children of both sexes, mGCT consist exclusively of teratomas and yolk sac tumors. The prognosis is generally favorable with modern treatment. In post-pubertal adults, virtually all patients with malignant mGCT are males; the prognosis is more guarded and depends (among other factors) on the histological GCT components and is similar to GCT in other organs. So-called somatic type malignancies (i. e. clonally related, non-germ cell neoplasias arising in a GCT) are much more frequent in mGCT than in other organs, and the association between mediastinal yolk sac tumors and hematological malignancies, such as myelodysplasias and leukemias, is unique to mediastinal tumors. The prognosis of GCT with somatic type malignancies is generally dismal.

Mediastinal Teratoma with Neuroendocrine Features in 34-Year-Old Male with Syncope

Neuroendocrine tumors that arise in an extragonadal teratoma are extremely rare. Somatic-type malignancy, defined as any sarcoma, carcinoma, leukemia, or lymphoma developing in a germ cell tumor, occurs in approximately 2% of all germ cell tumors. Our case represents a mediastinal mass that was incidentally found in a patient with syncope. Surgical resection confirmed mature teratoma with neuroendocrine features.

Ovarian Small Cell Carcinoma of Pulmonary Type Arising in Mature Cystic Teratomas With Metastases to the Contralateral Ovary

A bilateral small cell ovarian carcinoma pulmonary-type (SCCOPT), arising in bilateral mature cystic teratomas (MCTs) presented as stage IIIB in a 37-year-old woman. Microscopically, tumor nests were related to the dermoid protuberance and expressed pancytokeratin, EMA, CD56, chromogranin A, NSE, synaptophysin, and SOX2. SALL4 was also focally positive. CDX2, TTF1, PAX8, CK7, CK20, and several neuroendocrine gut hormones were negative. Serum NSE was elevated. This case represents a SCCOPT arising in an MCT in the right ovary with metastasis to the left one also containing a synchronous MCT. Surface implants and lymphovascular invasion suggested metastasis from the right ovarian SCCOPT and excluded a metastatic origin from usual locations of small cell carcinoma (SCC). SCCOPT is morphologically identical to SCC elsewhere, even sharing NSE serum elevation. Although the tumor was closely related to teratomatous mature tissues, a complex immunohistochemical panel failed to provide a tissue of origin.

Neuroendocrine carcinoma arising in a mediastinal teratoma with pulmonary metastasis: a case report and the chemotherapy response

Neuroendocrine carcinoma as a somatic-type malignancy (STM) arising in an extragonadal teratoma is extremely rare. The effect of chemotherapy has been poorly evaluated in such cases contrary to teratomas with other STMs. We herein demonstrate that systemic chemotherapy may be beneficial in a case of neuroendocrine carcinoma arising in a mediastinal teratoma with pulmonary metastasis. A 31-year-old man presented with mediastinal widening visualized on a chest radiograph. Computed tomography showed a huge mediastinal mass with two pulmonary nodules. Surgical resection confirmed the presence of a neuroendocrine carcinoma arising in a mediastinal teratoma and pulmonary metastasis. The patient subsequently received chemotherapy and has had no recurrence during the 28-month follow-up.

Mediastinal Teratoma with Coexisting Adenocarcinoma and Carcinoid Tumor (Somatic-Type Malignancy): A Case Report with a Review of the Literature

Germ cell tumors constitute 10% to 15% of anterior mediastinal neoplasms. Of these, mature teratoma is the most common. Somatic malignant transformation in mature teratoma is a very rare phenomenon. In the anterior mediastinum, few cases of malignant transformation in the form of carcinoma, sarcoma, or neuroendocrine tumors have been described. We present the case of a mature mediastinal teratoma in a 24-year-old female, diagnosed on computed tomography, where both carcinoid tumor and adenocarcinoma were seen. To the best of our knowledge, this is the first report of such a case. Malignant transformation in a mature teratoma confers a significantly worse prognosis and is difficult to diagnose only on clinical and radiological evaluation. As these lesions are so rare, the treatment options for these lesions are also not clearly defined. Extensive sampling and careful microscopic examination are needed when teratomas are submitted for pathological evaluation.