Introduction

A teratoma is a type of tumour that derives from pluripotent germ-cells. Teratomas usually begins from cells in the testes in men, the ovaries in women, and in the sacrum in children. Although teratoma is commonly found both in gonadal organs and at extragonadal sites such as the mediastinum, sacrococcygeum, and pineal region, teratomas rarely found in organs (₁,₂). They can be benign or malignant. Malignant transformation of teratoma in the anterior mediastinum is rare (₃,₄).

Case Report

A 28-years old woman in whom a mediastinal mass was admitted to hospital, complaining chiefly of dyspnea. She was married and had no child. Chest radiograph showed a mediastinal enlargement that a 10X12 cm mass in the anterior mediastinum as well as ill-defined consolidation in the left upper lobe. Computerised tomography scanning demonstrated a lobulated, inhomogeneous cystic mass with a fat component and calcification in the anterior mediastinum (Figure 1). Serum α-feto protein and carbohydrate antigen 15-3 and 19-9 levels are in nornal limits.

Figure 1

Figure 1: Computerised tomography of thorax showed a lobulated, inhomogeneous cystic mass and the lateral wall of the mass has consolidation with the fat component in the adjacent left upper lobe. Also localised heterogeneous enhanced solid portion with calcific sections (teeth) situated in left anterosuperior mediastinum suggesting presence of teratoma was noted in the medial aspect of the mass and extended to the upper mediastinum, 10x8x6 cm in size. Left ventricle and left upper pulmonary lobe are compressed by the mass.

Surgical Technique

After general anaesthesia and intubation with a double-lumen endotracheal tube, left posterolateral thoracotomy was performed and huge tumorous mass spreading up to lipoid tissue of anterosuperior mediastinum was observed. A well encapsulated tumour without infiltrations on adjacesent structures measuring 10x8x6 cm was seen. The adhesions between tumorous mass and left superior lobe, left pulmonary artery, and left superior pulmonary vein were carefully separated by sharp and blunt dissections. Pathohistological examination confirmed a benign cystic mature teratoma by microscopically (Figure 2). Patient’s postoperative period was uneventful and was discharged postoperative forth day.

Figure 2

Figure 2: Microscopically: Cystic lumen was covered with squamous epitelium (a) smooth muscle tissue and mature lipoid tissue (b) respiratuar epitelium (c), glial tissue (d) and cartilage islands (e).(H&E, X25, X100, X50, X50,X25)

Discussion

Teratomas involve cells from all three embryonic cell layers: ectoderm, mesoderm, and endoderm (₁). Teratomas of the mediastinum have low incidence rate constituting only 8-13% of all tumours in this region and only 1-10 % of germ-cell tumours are found in the mediastinum which is mostly seen in anterior compartment of mediastinum (₁). Benign mediastinal teratomas are seen in equal frequency in women and men, but malignant teratomas are more common in men (₂). Many of germ-cell tumours are observed both in children below 7 years of age and in young adults between 15 to 35 years of age (₃). Mediastinal germ-cell tumours exhibit poor prognosis that only 30 to 40% of patients are cured (₄) and long-term survivers have occurence of malignant transformations such as sarcomas adenocarcinomas, neuroblastomas and haematological malignancies (₄,₅).

In our case the patient was a 28 years old female presenting with dyspnea. Although many of the component tissue may reach full maturation, usually they do not have physicological capacities. The teratomas cause signs and symptoms by their mechanical effect rather than functional activity. In our patient the symptoms were caused by the physical mass of the tumour.

Benign mediastinal tumours are uncommon and often found while still asymptomatic or incidentally at chest x-ray. In our case chest x-ray of patient revealed a mediastinal enlargement that was not diagnostic for a mature teratoma but thoracal computerised tomography demonstrated a lobulated, inhomogeneous cystic mass with a fat component and calcification in the anterior mediastinum and revealed as a propable mature teratoma before the operation and the patient underwent operation with that preoperative diagnosis.

As a conclusion almost all teratomas arise in the anteriosuperior mediastinal compartment and most of symptoms result from compression of adjacent structures. The tumor was succesfully treated by surgical excission with no recurrence. Surgery should be performed because of propable complications such as atelectasis of compressed lung tissue, adhession to or compression of adjacent structures, and malignant trasformation even if it is benign.

Correspondence to

Bilgehan Savaş ÖZ Gülhane Askeri Tıp Akademisi Kalp ve Damar Cerrahisi Etlik / Ankara / TURKEY 06010 Phone: 00 90 312 2860668 bsavasmd@hotmail.com bsavoz@yahoo.com