Computed tomography of the thymus of children under 10 years

Computed Tomography in the Diagnosis and Treatment of Mediastinal Abnormalities in Children

Thirty-one children with mediastinal abnormalities—14 malignant lymphomas, 4 other primary malignancies, one metastatic and 12 benign lesions—were examined one or several times using CT, which proved to be effective especially for cysts (5 patients), ductus arteriosus aneurysm (2 patients), and intrathoracic liver (one patient). It also supplied important diagnostic information regarding the extent of disease in malignant thymoma (one patient), in neurinoma (one patient), and in Hodgkin's lymphoma (5 patients). It was found to be useful in the monitoring of treatment of patients with lymphomas, in which a small residue, probably a fibrotic remnant, was invariably seen after completion of chemotherapy and irradiation. It was concluded that when the residue was enlarged, the possibility of relapse and even thymic hyperplasia should be considered. However, if CT was performed under general anaesthesia pseudo-widening of the anterior mediastinum could simulate recurrence. Surgical biopsy was found to be necessary in these cases because fine-needle aspiration biopsy was unsuccessful.

Normal thymic uptake of FDG on PET imaging

Assessment and characterization of the thymus by various imaging methods have been extensively described. The authors report increased uptake of 2-(18)Fluoro-2-deoxy-D-glucose (FDG) in the normal thymus gland of patients between the ages of 2 and 13 years. Most of these patients had PET scans for various oncologic conditions and had no clinical problems referable to the thymus gland. This uptake assumes an important role when evaluating mediastinal uptake in whole-body PET scans in pediatric oncology patients to avoid false-positive interpretation.

Respiratory complications in cervical thymic cysts

Thymic cysts are considered uncommon lesions in the differential diagnosis of pediatric neck masses. They have been described as asymptomatic and of little clinical consequence. Recent reports have stressed the possibility of respiratory compromise associated with these lesions. We reviewed our experience with cervical thymic cysts with emphasis on respiratory problems. Ten pediatric patients underwent surgery and were found to have cervical thymic cysts. Ages ranged from newborn to 14 years. There were four boys and six girls. Two were found to have the thymic cysts at time of neck exploration for Grave's disease and hyperparathyroidism. Of the remaining eight patients, all had mobile cystic masses, located anterior to but extending beneath the lower third of the sternocleidomastoid muscle. The size of the mass ranged from 3.0 to 8.5 cm. Preoperative diagnosis included cystic hygroma/branchial cleft cyst (five), lymphoma (one), teratoma (one), and thymic cyst (one). All had a history of rapidly developing neck mass. Seven of the eight gave a history of upper respiratory tract infection (URI) prior to the development of the mass. Five had imaging studies that showed tracheal compression. Three of these required airway management in the early postoperative period. All were excised through a neck incision, with two requiring sternal extension. Histology showed cholesterol crystals, Hassall's corpuscles, and giant cell reaction diagnosis of thymic cysts. There has been no recurrence and no permanent respiratory sequela in the ten patients. Cervical thymic cysts are benign lesions that may be more common than literature suggests.(ABSTRACT TRUNCATED AT 250 WORDS)

Change of thymic size during and following cytotoxic therapy in young patients

In a retrospective study, 108 thoracic CT-scans of 18 patients aged 5-25 who had received cytotoxic treatment for solid tumors were evaluated. The thymic size decreased in 15/17 patients during treatment and increased in 14/15 after the end of therapy. In 5/5 patients, the change could also be detected with relapse therapy. These changes have to be considered in the evaluation of a mediastinal mass suspected of metastasis during and following cytotoxic therapy.