Mediastinal cystic teratoma

Clinical case: cystic teratoma

The classic manifestation of the disease often includes pain syndrome. As an example, we can consider a female patient (8 years old) who had experienced intermittent chest pain for two years.

• Chest radiography: the images clearly visualize a mass lesion located in the anterior mediastinum.
• Contrast-enhanced CT: in the coronal and sagittal projections, the lesion is predominantly cystic in nature. A key diagnostic sign is a thick, nodular (nodular) wall that intensely accumulates the contrast agent.

The definitive diagnosis is established pathomorphologically: following surgical excision of this lesion, the presence of a mature teratoma (mature teratoma) is confirmed.

Differential diagnosis: lymphadenopathy in hemoblastoses

When evaluating mediastinal masses, it is important to differentiate them from enlarged lymph nodes. Lymphadenopathy can accompany various hemoblastoses, including leukemias (leukaemia).

The radiological pattern in leukemias is often completely analogous to the picture observed in lymphomas (lymphoma). An important clinical and radiological feature is that enlarged lymph nodes (both in lymphoma and in leukemia) are capable of regressing extremely rapidly during adequately administered therapy.

Lymph node calcification

The most sensitive method for detecting lymph node calcification is CT. The causes of this phenomenon are divided into several groups:

1. Extensive calcification (frequent causes): tuberculosis (tuberculosis) and various fungal infections (fungal infection).
2. Other non-metastatic causes: sarcoidosis (sarcoidosis), silicosis (silicosis), amyloidosis (amyloidosis), and other infections.
3. Metastatic involvement: calcifications are typical for metastases of osteosarcoma (osteosarcoma), chondrosarcoma (chondrosarcoma), as well as mucinous tumors of the ovaries and colon. They are rare in other metastases.
4. Lymphomas: calcification is virtually absent in patients with untreated lymphomas. It may occur only in nodes following therapy for Hodgkin's lymphoma (Hodgkin disease).

Specific CT calcification patterns

There are two main types of calcification distribution:

• Coarse, unevenly distributed nodules within the node.
• Homogeneous calcification of the entire lymph node.

Special attention is paid to specific patterns:

• «Foamy» appearance (foamy appearance): a rare pattern. It is found in patients with acquired immunodeficiency syndrome (AIDS) with Pneumocystis jiroveci infection, as well as in certain metastases of mucinous neoplasms.
• Eggshell calcification: ring-like calcification strictly along the periphery of the node. This is a characteristic sign of sarcoidosis and prolonged exposure to industrial dust (e.g., silicosis in the mining industry).

Low-attenuation lymph nodes

Areas of low attenuation within enlarged lymph nodes on CT correspond to areas of necrosis (necrosis).

This sign is observed in various pathologies, but it is especially characteristic of tuberculosis involvement. Areas of necrosis in lymph nodes are also found in fungal diseases and a number of other infectious processes.

Class and exam questions

What else to study on this topic

• Pathomorphological criteria of a mature teratoma
• Specifics of metastasis in mucinous tumors
• Differential diagnosis of necrosis and cystic transformation on CT
• Radiological picture of Pneumocystis jiroveci infection in AIDS

Other topics in the «Chest Radiology» section

Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.