Diagnosis Of Thymic Hyperplasia Research Articles

Les hyperplasies thymiques

Thymic hyperplasia presents as an anterior mediastinal mass and poses important diagnostic and therapeutic challenge. Two types of thymic hyperplasia are described: true hyperplasia and follicular hyperplasie. Literature data are peculiar concerning both entities. We aimed to describe the clinical and microscopic characteristics of thymic hyperplasia through a single institution experience during an 11-year-period.Thymic hyperplasia diagnosed during the period between 2009 and 2020 were included.In all, 46 thymic hyperplasias were diagnosed. The 46 patients consisted in 33 women and 13 men with a mean age of 30 years. Microscopic diagnosis concluded to a follicular hyperplasia in 12 cases and a true thymic hyperplasia in 34 cases. The diagnosis of true thymic hyperplasia posed a diagnostic challenge with an involuted thymus in 1 case and a thymolipoma in 1 case. The confrontation with the clinical data allowed retaining the diagnosis.The diagnosis of thymic hyperplasia is based on microscopic features. The confrontation with clinical data and the measurements of the thymus according to the age allow to retain the diagnosis in most challenging cases.

EP16.04: Prenatal diagnosis of thymic hyperplasia: case report

EP16.04: Prenatal diagnosis of thymic hyperplasia: case report

Investigating Factors Associated with Thymic Regeneration after Chemotherapy in Patients with Lymphoma.

The factors involved in thymus regeneration after chemotherapy has not been sufficiently explored. This study was aimed to identify the clinical characteristics and single-nucleotide polymorphisms in the gene (IL7R) encoding IL-7Rα associated with thymus renewal after chemotherapy in Chinese Han individuals with lymphoma. The dynamics of thymic activity in 134 adults with Hodgkin lymphoma (HL) and B cell lymphoma from baseline to 12 months post-chemotherapy were analyzed by assessing thymic structural changes using serial computed tomography scans and correlating these with measurements of thymic output by concurrent analysis of single-joint T-cell receptor excision circles (sjTREC) and CD31+ recent thymic emigrants (RTE) in peripheral blood. The association of clinical variables and IL7R polymorphisms with the occurrence of rebound thymic hyperplasia (TH) and the recovery of thymic output following chemotherapy were evaluated. Thymic regeneration was observed, with the evidence that TH occurred in 38/134 (28.4%) cases, and thymic output, assessed by CD31+ RTE numbers and sjTREC content, recovered to baseline levels within 1 year after the end of therapy. The frequencies of the T allele and TT + GT genotype of rs7718919 located in the promoter of IL7R were significantly higher in patients with TH compared with those without TH (P = 0.031 and 0.027, respectively). In contrast, no significant difference was found between two groups with respect to the distribution of allele and genotype frequencies of rs6897932. By general linear models repeated-measure analysis, rs7718919 and rs6897932 were determined to exert no significant effects on the recovery of thymic output after therapy. Univariate analysis revealed host age under 30, the diagnosis of HL, baseline thymic index and CD31+ RTE counts, and rs7718919 genotype as potential predictors for TH after chemotherapy (P < 0.05); after multivariate adjustment, only host age was independently associated with the occurrence of TH (odds ratios = 4.710, 95% confidence intervals: 1.727–12.845, P = 0.002). These findings indicate that patient age is an independent predictor for thymic regrowth after chemotherapy, which should promote awareness among physicians to make a timely diagnosis of TH in young adults and help physicians to prioritize intervention strategies for thymus rejuvenation in this population.

P09. Diagnosis of advanced thymic epithelial tumors in patients previously affected by thymic hyperplasia

Background Thymic hyperplasia is a rare differential diagnosis of anterior mediastinal lesions. Histological and radiological criteria are used to distinguish this benign condition from other malignant diseases; it is often associated with Myasthenia gravis. Here we report our monocentric experience of five patients, affected by advanced thymic epithelial tumors (TETs), with a previous diagnosis of thymic hyperplasia.

Should asymptomatic enlarged thymus glands be resected?

Patients frequently have an "enlarged thymus" incidentally identified on imaging. We sought to determine whether thymectomy is appropriate in patients with diffusely enlarged thymus glands. A retrospective review was conducted of patients undergoing thymectomy without myasthenia gravis at 1 institution over 15 years. Of 117 patients undergoing thymectomy, 109 patients had complete data. Thirty-six had a gland judged by the surgeon to be diffusely enlarged, and 73 had a discrete mass. Of the 36 diffusely enlarged thymus glands, 18 (50%) occurred in patients with no symptoms referable to the thymus. No patient (0/18; 0%) with an asymptomatic diffusely enlarged thymus gland had a pathologic diagnosis that would have required resection (8 normal; 10 "hyperplasia"). Of the 18 symptomatic patients with diffusely enlarged glands, 4 (22.2%) harbored lymphoma, but none harbored thymoma or other tumor (P<.05; symptomatic vs asymptomatic). Of the 73 patients with discrete masses, 45 (61.6%) were symptomatic, and both the symptomatic and asymptomatic patients had a high rate of pathologic diagnoses that represented an indication for resection (53.3% and 42.8%, respectively, harbored thymoma or other tumor). Of the 25 (of 109) patients initially having a diagnosis of thymic hyperplasia, only 3 (12%) had true follicular hyperplasia on re-review of the pathologic condition. Interestingly, an autoimmune disorder developed in 2 (67%) of these 3 patients on long-term follow-up. Asymptomatic patients with diffusely enlarged thymus glands can be followed up expectantly because they have a negligible incidence of significant thymic disease; symptomatic patients with diffusely enlarged thymus glands may have lymphoma, so biopsy is appropriate. Half of patients with a discrete mass have tumors requiring resection; imaging advances would be useful to better differentiate among patients within this group.

Ectopic Thymic Hyperplasia in a Patient Treated for Burkitt Lymphoma

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.

Thymic Hyperplasia in a Patient with Graves’ Disease

A 23-yr-old man who was previously healthy was evaluated after a fall. Computed tomography of the chest showed an anterior mediastinal mass. Percutaneous biopsy showed benign thymic tissue. Three months later the patient developed ophthalmopathy and signs and symptoms of hyperthyroidism. Serum-TSH level measured less than 0.004 IU/ml (0.35–5.50 IU/ml), serum-free T4 4.93 ng/dl (0.61– 1.76 ng/dl), and serum-thyroid peroxidase antibody more than 70 IU/ml ( 2 IU/ml). Radioiodine uptake was increased in a diffusely enlarged gland. Based on these findings, the patient was diagnosed with Graves’ disease. The patient was treated with radioactive iodine. His thyroid decreased substantially in size, but a repeat chest computed tomography 1 month later demonstrated persistence of the mediastinal mass (Fig. 1). The patient complained of pain and a sensation of fullness and obstruction in his chest; thus, radical thymectomy was performed. The thymus was enlarged and measured 11.5 7.5 3 cm. Pathology revealed thymic follicular hyperplasia with focal germinal center formation. There is a rare but well-documented association between Graves’ disease and thymic hyperplasia (1). In most cases thymic enlargement is minimal; however, it may occasionally present as an appreciable anterior mediastinal mass (2). Whereas surgical resection has been a common treatment of such a mass, the literature supports following up the mass closely (3). A decrease in size after treatment of the hyperthyroidism supports the diagnosis of thymic hyperplasia, and thymectomy can be avoided (3). Clinicians should be aware of the usually benign clinical course of thymic hyperplasia associated with Graves’ disease.

Combined True Thymic Hyperplasia and Lymphoid Hyperplasia in Grave's Disease

True thymic hyperplasia (enlarged gland composed of histologically unremarkable cortical and medullary parenchyma) and lymphoid hyperplasia (medullary lymphoid follicles in the clinical setting of autoimmunity) usually develop as independent pathologic processes. We reviewed the clinical features and gross and microscopic pathology of 2 hyperthyroid patients with features of both thymic hyperplasia and lymphoid hyperplasia. The diagnosis of thymic hyperplasia was supported by thymic weights greater than two standard deviations above the mean weight for age and histologic evidence of expanded cortical and medullary parenchyma. The diagnosis of lymphoid hyperplasia was supported by the increased number and size of medullary lymphoid follicles and the association with Graves' disease. This unusual combination results from two separate pathogenic mechanisms operating simultaneously in hyperthyroid patients. Elevated thyroid hormones directly stimulate the proliferation of thymic epithelium, producing thymic hyperplasia. The immune abnormalities underlying Graves' disease can also result in lymphoid hyperplasia of the thymus.