Metastatic seminoma of supraclavicular lymph node

Seminoma is a tumour of the germ cells, which produce eggs and sperm in females and males respectively. In this case, the seminoma has metastasized (spread) through the lymphatic system to a lymph node located above the collarbone, presenting as a mass of the neck. A sample was obtained using a fine needle biopsy and stained for diagnosis using the MGG (May Grünwald Giemsa) stain. Seminomas are characterized by the presence of large fragile tumour cells (large purple cells) mixed with lymphocytes, a type of white blood cell (small, dark purple cells). Red blood cells can be seen here also (orange/pink cells). The cytoplasm of the tumour cells contains glycogen, the storage form of glucose. In air dried and MGG stained smears the glycogen rich fragile cytoplasm of the neoplastic cells forms a spotted network known as a "tigroid" background. Horizontal image width 336 micrometres.