Ectopic Thymic Hyperplasia in a Patient Treated for Burkitt Lymphoma

Abstract

Thymic hyperplasia results from thymic regrowth after atrophy during stressful conditions such as burns, surgery, infection, and chemotherapy. Although thymic lesions are relatively common causes of anterior mediastinal masses, they also can develop in other mediastinal compartments on rare occasions. It is well known that thymic tissue can develop in ectopic intrathoracic lesions. Few cases of ectopic thymus associated with disturbance during thymus embryogenesis have been reported as incidental findings. We report the case of a 4-year-old boy with true thymic hyperplasia from an ectopic thymus after successful treatment for Burkitt lymphoma. This is a rare finding in the differential diagnosis of a middle mediastinal mass in a child following chemotherapy for lymphoma. The diagnosis of thymic hyperplasia from an ectopic thymus can be confirmed only histologically.

The role of PET-CT in the differential diagnosis of thymic mass after treatment of patients with lymphoma

“…The differential diagnosis of mediastinal masses after successful treatment of lymphoma consists of residual fibrosis and necrosis of the primary tumor, recurrence of disease, thymic cyst, thymic hyperplasia, pulmonary fibrosis or granulocytic sarcoma [2,4]. In the literature, CT, magnetic resonance imaging, 67 Gallium scintigraphy and 18 F-FDG PET-CT have been reported to be useful methods for the differential diagnosis of these mediastinal masses but there are limitations to each of these imaging techniques [2,5]. Thymic malignancy can be differentiated from thymoma on the basis of biologic behavior such as local invasiveness and distant metastasis (3).…”

“…However, this entity has rarely been described in older patients [1]. The occurrence of a mediastinal mass in patients following complete remission (CR) from Hodgkin's lymphoma (HL) frequently indicates relapse but some benign processes like thymic hyperplasia may present with similar features [4,5]. After CR of testicular carcinoma, thymic hyperplasia has also been reported [6].…”

Xanthogranulomatous Appendicitis Mimicking Residual Burkitt's Lymphoma After Chemotherapy

“…Relapses of Burkitt's lymphoma, which most commonly occur within 6 months of completion of treatment, are associated with poor outcomes [ 1 ]. In clinical practice, remnant masses have been observed on imaging studies after completion of intensive chemotherapy in several cases [ 10 11 ]. Son et al [ 11 ] reported a case of ectopic thymic hyperplasia after chemotherapy for Burkitt's lymphoma.…”

“…In clinical practice, remnant masses have been observed on imaging studies after completion of intensive chemotherapy in several cases [ 10 11 ]. Son et al [ 11 ] reported a case of ectopic thymic hyperplasia after chemotherapy for Burkitt's lymphoma. Karmazyn et al [ 10 ] reported 7 patients with residual abdominal masses among 33 children with abdominal Burkitt's lymphoma who were confirmed to be in complete remission after chemotherapy.…”