Recurrent mediastinal mass in a child with Hodgkin's disease following successful therapy: a diagnostic challenge

Predictors for reactive thymic hyperplasia and its prognostic value in children and adolescents with lymphoma

BACKGROUND

Reactive thymic hyperplasia (RTH) is seen in children and adolescents receiving chemotherapy for various malignancies. However, it is not clear why this occurs only in some patients. The aim of this study was to identify the predictors for RTH in children and adolescents receiving chemotherapy for lymphoma and to determine the effect of RTH on prognosis.

METHODS

We reviewed the medical records of 126 lymphoma patients (October 2007-October 2012). The patients were divided into two groups according to different criteria, i.e., age at initial diagnosis (2-12 years vs. 13-18 years); presence of thymic infiltration at baseline (yes vs. no); and receipt of mediastinal radiotherapy (yes vs. no). The Kaplan-Meier method and multivariate Cox regression model analysis were used to analyze predictors for RTH. Further, patients were divided into two groups according to the occurrence of RTH during follow-up, and Kaplan-Meier survival analysis was used to analyze the prognostic value of RTH.

RESULTS

The 2-12-year-old group had a shorter duration from the end of therapy to RTH than the 13-18-year-old group (median: 3 months vs. 16 months) and a higher rate of RTH (97.1% vs. 60.3%, P < 0.001). The lymphoma thymic non-infiltration group had a shorter duration from the end of therapy to RTH than the lymphoma infiltration group (median: 4 months vs. 22 months), and a higher rate of RTH (88.2% vs. 57.6%, P < 0.001). The non-mediastinal radiotherapy group had higher rate of RTH than the mediastinal radiotherapy group (84.7% vs. 12.5%, P < 0.001). Low age, absence of thymic infiltration by lymphoma at baseline, and absence of mediastinal radiation were predictors for RTH by multivariate Cox regression analysis (P < 0.05). The RTH group had a lower recurrence rate than the non-RTH group (13.9% vs. 40%), and a longer duration from the end of therapy to recurrence (median: 10 months vs. 5 months, P < 0.001).

CONCLUSIONS

Younger age, absence of thymic infiltration by lymphoma at baseline and absence of mediastinal radiotherapy are predictors for RTH in children and adolescents. RTH may be a positive prognostic factor.

Nasopharyngeal lymphoid hyperplasia after therapy for childhood lymphomas

Although diffuse thymic hyperplasia after therapy has been reported in lymphomas, no report is found in the medical literature about hyperplasia of other lymphoid tissues following chemotherapy in malignancies as far as we could reach. So, we planned to investigate the nasopharyngeal region of the lymphoma cases during their follow-up while at remission. Children who were in follow-up after cessation of oncological therapy with the diagnosis of lymphoma were evaluated for their nasopharyngeal lymphoid tissues by means of computed tomography. When a mass lesion was diagnosed, biopsies were taken. Among 23 lymphoma cases in follow-up, at a median of eight months (range 1-13 months), eight patients (six Hodgkin's and two Non-Hodgkin's malignant lymphoma) developed nasopharyngeal lymphoid hyperplasia (34.78%) that were proven to be benign by means of biopsies. Two of the patients also developed thymic hyperplasia. Nasopharyngeal hyperplasia regressed in four patients at a median of four months. Nasopharyngeal lymphoid hyperplasia may be diagnosed after the cessation of therapy in lymphomas and whatever the cause, it seems to be a benign process.

Accumulation of gallium-67 within mature and immature teratoma in pediatric patients: investigation for the uptake mechanism

OBJECTIVE

We encountered cases of mature and immature teratoma with positive uptake of (67)Ga. The objective of this study is to investigate the mechanism of (67)Ga accumulation within mature and immature teratomas by comparing the findings of gallium scan, computed tomography (CT), and autoradiography of surgical specimens with the pathological findings.

METHODS

The subjects comprised 14 children who underwent surgical resection for intra-abdominal mature and immature teratomas, which were histologically proved to be of the mature and immature subtype. Their age ranged from 24 days to 14 years. The origins of the mature teratomas consisted of seven ovaries including one bilateral case, two retroperitoneal, and two sacrococcygeal regions. The origins of the immature teratomas were retroperitoneum in two cases, an ovary and a sacrococcygeal region. Complete surgical excision was feasible in all children. They underwent both gallium scan and CT prior to surgery. Single-photon emission computed tomography was added in some cases. For two gallium-positive cases, radiography and scintigraphy (autoradiography) of the resected specimen were performed.

RESULTS

Of the 14 children, 5 (one with immature and four with mature subtype) showed positive (67)Ga uptake within tumors, which originated from the retroperitoneum in the 3 boys, and from the ovary in the 2 girls. All had typical CT findings of teratoma, including calcifications, fat components, cystic areas, and solid parts. (67)Ga accumulation in the four mature teratomas appeared discretely strong, and was considered to correspond with intralesional calcifications. However, in the remaining one immature teratoma, the gallium distribution was diffuse within the tumor. The comparison between radiography and autoradiography of the resected mature teratomas confirmed the correlation between the intralesional calcifications and areas of (67)Ga accumulation.

CONCLUSIONS

A high-uptake ratio of (67)Ga in benign teratoma was indicated. A close correlation between gallium scan and CT helps to ascertain whether (67)Ga uptake results from malignant and/or immature elements, or mature tissue components.

Cervical thymic rebound after cancer treatment

While newly recognized neck masses in children previously treated for malignancy raise the specter of recurrent disease, recent experience with 2 patients has shown us that enlargement of cervical thymic tissue should be considered in the differential diagnosis, especially early after the completion of chemotherapy or immunotherapy.

Thymic and adenotonsillar enlargement after successful treatment of malignancies

Anterior mediastinal and adenoid masses in children after cessation of chemotherapy for malignant disease often cause a diagnostic problem. Differential diagnosis of thymic enlargement and adenoid hyperplasia from recurrence frequently poses a challenge both for the radiologist and the physician. In this study the authors evaluated 491 patients with different malignant tumors for thymic and adenoid hyperplasia. Thymic hyperplasia was seen in 18 patients (5 Hodgkin disease (HD), 5 non-Hodgkin lymphoma (NHL), 4 Wilms tumor, 2 germ cell tumor, 1 Ewing sarcoma, and 1 neuroblastoma), only adenotonsillar hyperplasia was seen in 6 patients, all with NHL, and both thymic and adenotonsillar hyperplasia were seen in 3 patients (1 HD, 2 NHL). In 5 patients, adenoid hyperplasia was proven by biopsy; 1 patient underwent to adenoidectomy. Their histopathologic investigation showed polyclonal follicular hyperplasia. The authors recommend that patients with thymic and/or adenotonsillar enlargement after successful treatment of their primary malignancy should be evaluated cautiously before an invasive procedure is planned.

Thymic epithelial hyperplasia with nodular sclerosis Hodgkin's disease

We report a case of simultaneous occurrence of thymic epithelial hyperplasia and Hodgkin's disease. A computed tomographic scan of the chest revealed a tumor in the anterior mediastinum and conspicuous swelling of lymph nodes in the upper and lower mediastinum. The anterior mediastinal tumor was histologically diagnosed as thymic epithelial hyperplasia, while the lymph nodes were nodular sclerosis Hodgkin's disease. Our findings suggest that thymic hyperplasia might be directly involved in the pathology of at least some cases of Hodgkin's disease.