Fine-needle aspiration cytology of unusual germ cell tumors of the mediastinum: atypical seminoma and parietal yolk sac tumor

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.

Fine needle aspiration of mediastinal germ cell tumors

Germ cell tumors in the mediastinum are rare and often occur in young patients but may occur in older patients. Seminoma, embryonal carcinoma, yolk sac tumor, choriocarcinoma and teratoma have distinct morphologic features with high grade nuclei. They are the primary diagnostic consideration in young males but may be lower on the list in older patients, where they may be misdiagnosed as carcinomas. Review of the history, use of immunohistochemistry stains and recognition of morphologic features will help to make the diagnosis of germ cell tumor of the mediastinum. These tumors have a good to intermediate prognosis, depending on when they are detected.

Cytology of mixed germ cell tumor with mediastinal metastasis

Nonseminomatous germ cell tumors of the testis are common and are very aggressive malignant tumors. Most of the cases have metastases at the time of diagnosis, and involvement of the posterior mediastinum in particular is well known. A 33 year-old male patient presented with complaints of a swelling on the right side of the neck that had been growing for the last month, as well as shortness of breath and cough. His thoracic computed tomography (CT) showed a 1.5 cm lymph node on the anterior mediastinum and a mass of about 11 × 10 × 8 cm extending from the right lung apex to the right hilus, with regular contours and without contrast enhancement. The patient, who was given the preliminary diagnosis of a mixture metastatic bronchial tumor plus lymphoma, was subjected to transthoracic fine needle aspiration cytology (FNAC). His abdominal CT revealed a hypodense, heterogeneous and cystic necrotic mass of about 10 × 7 × 5 cm that was para-aortic at the infrarenal level (initially predicted as a lymphoma). The patient, who could not be typed in his cytopathological examination, was diagnosed with malignant epithelial tumor and was recommended to undergo a genitourinary system examination. Upon finding a high alpha fetoprotein (AFP) value, a scrotal ultra sonography was performed which showed a mass filling the right testis. Histopathological examination of the orchiectomy material resulted in the diagnosis of mixed germ cell tumor (60% mature teratoma and 40% yolk sac tumor). Even though metastatic lesions are mostly seen in the posterior mediastinum, our findings reveal that specimens obtained with FNAC from the anterior mediastinum bear discohesive, pleomorphic, small nuclei in epithelial cells with microvacoules in the cytoplasm. These cytopathological alterations in specimens from the anterior mediastinum might promote germ cell and yolk sac tumors.

Apport de la cytoponction dans le diagnostic des tumeurs germinales extragonadiques

Extragonadic germinal tumors are frequently mixed tumors. When a metastatic sacrococcygeal teratoma is clinically suspected in children, a yolk-sac tumor component could be judiciously demonstrated by either an elevated serum level of alphafoetoprotein (AFP), or fine needle aspiration cytology. We report the case of a 25 month aged girl presenting a metastatic sacrococcygeal tumor (lymph node and bone metastasis) with high level of AFP (34.100 microg/ml). Fine needle aspiration cytology identified the yolk sac tumor component, characterized by papillae and glandular clusters, composed of pale isomorphic cells with vesicular and nucleolated nucleus and some intracytoplasmic hyaline globules. The yolk sac tumor component could not be identified in the sacrococcygeal surgical specimen, exclusively composed of immature teratoma.