Multilocular thymic cysts in children with human immunodeficiency virus infection: clinical and pathologic aspects

Multilocular thymic cyst detected during COVID‑19 treatment in an HIV‑positive adult man: A case report and literature review

A multilocular thymic cyst (MTC) is a rare mediastinal tumor with multiloculated cyst-like structures in the anterior mediastinum. This tumfor is associated with inflammatory diseases, including human immunodeficiency virus (HIV) infection. The present study reports a case of MTC detected during coronavirus disease 2019 (COVID-19) treatment in an adult who was tested HIV positive. An anterior mediastinal tumor was incidentally detected on computed tomography in a 52-year-old man with a 20-year history of HIV infection on the 9th day of COVID-19. The patient was asymptomatic with no notable physical findings. Magnetic resonance imaging revealed a 28-mm bilocular cyst. Robot-assisted thoracoscopic tumor resection was performed. Pathological examination showed that the cyst was lined with squamous or cuboidal epithelium, and the cystic lesion wall was mainly composed of thymic tissue with follicular hyperplasia. Based on these findings, the patient was diagnosed with MTC. To date, only 15 MTC cases have been reported in patients with HIV, and the majority of cases showed HIV infection-related symptoms such as lymphoid interstitial pneumonia and parotid gland enlargement. The present case was atypical for an HIV-related MTC because it did not involve HIV infection-related symptoms, suggesting the possibility for an alternative etiology such as COVID-19. Further reports on MTC development in patients with COVID-19 are required to elucidate the relationship between MTC and COVID-19.

Multilocular Thymic Cyst in a Patient with Untreated HIV/AIDS: Case Report and Review of the Literature

BACKGROUND

Multilocular thymic cysts (MTCs) in adults with human immunodeficiency virus (HIV) are rarely reported.

CASE PRESENTATION

We describe a case of symptomatic MTC in a male with untreated HIV. A presumptive diagnosis was established based on radiographic imaging and biopsy. Pathologic diagnosis and exclusion of malignancy were ultimately confirmed the following thymectomy. In conjunction with starting antiretroviral therapy, the patient recovered well post-operatively with a resolution of his presenting symptoms.

CONCLUSION

Our case report and review of the literature serve to highlight MTCs as an important clinical entity occurring in persons with HIV.

The histological properties and possible origin of cervical thymus with cysts - A case report and hypotheses about its development

Ectopic accessory thymic tissue usually presents as an asymptomatic neck mass found at any level corresponding to the embryonic descent of the thymus. This tissue may contain smaller or larger cysts. However, the exact pathogenesis of "enigmatic" cervical thymic cysts remains controversial. A 7-year-old boy was referred to our workplace for the evaluation of a cervical mass. An ultrasound suggested a multi-loculated cystic mass, while CT and MRI indicated a left-sided, anteriorly located cervical mass beneath the sternocleidomastoid muscle. Following the radiological findings, surgical excision revealed a cystic mass. The mass of tissue was covered by a capsule. In H&E staining, the cervical mass had the same structure as normal thymus. Additionally, immunohistochemical findings suggest that the cellular microenvironment of cervical thymus also displays a place for development of T-lymphocytes. Within the parenchyma multiple cysts lined with cytokeratin-positive thymic epithelial cells were found. Inside the cysts, there were CD68-positive multinucleated giant cells and cholesterol clefts. A tendency to cystic degeneration inside the thymic tissue occurs more often in cervical thymuses than in normally located ones. The reason for the formation of cysts is unknown. We summarized seven possible histological, embryological and evolutional backgrounds for the development of these thymic cysts.

Large Multilocular Thymic Cyst: A Rare Finding in an HIV Positive Adult Female

Multilocular thymic cysts with follicular hyperplasia are uncommon masses that occur in Human Immunodeficiency Virus (HIV) positive individuals. These cysts mostly present in HIV positive children. Here we report a rare case of multilocular thymic cyst in an HIV positive adult female. In this case report, the radiologic findings of multilocular thymic cyst, management and prognosis are discussed.

Giant multilocular thymic cyst in an HIV-infected adolescent

A girl with vertically acquired HIV infection presented with a 6-month history of dyspnea and chest pain. Computed tomography of the thorax showed a heterogenous mass measuring 13 × 9 × 17 cm located in the anterior mediastinum. Complete surgical resection was accomplished with no complications. The final diagnosis was multilocular thymic cyst, a distinct pathologic entity that is morphologically distinguishable and unrelated to congenital thymic cyst.

Acute respiratory failure revealing a multilocular thymic cyst in an infant: a case report

Introduction

Multilocular thymic cysts are rare benign lesions of the neck and mediastinum that can occur at any age. In children, multilocular thymic cysts are usually symptomatic after the age of 2 years and produce few symptoms. We present an unusual case of a multilocular thymic cyst diagnosed in a 3-month-old girl and causing severe respiratory failure.

Case presentation

A 3 month-old-girl, with a medical history of dyspnea and wheezing since the age of 20 days, presented in our pediatric intensive care unit for acute respiratory failure requiring mechanical ventilation. The chest radiograph showed thoracic distension without any other abnormalities. The diagnosis of severe asthma was initially suspected and the patient was treated by intravenous corticosteroids and continuous perfusion of salbutamol without any improvement. A chest tomography scan was performed and demonstrated an anterior mediastinal multiseptated cystic mass extending from the inferior face of the thyroid gland to the left cardiophrenic angle. Sternotomy and excision biopsy were planned urgently. The cystic mass was excised completely. The histopathological examination confirmed the diagnosis of a multilocular thymic cyst.

Conclusion

The particularities of our observation are the occurrence of a multilocular thymic cyst in a young infant and its presentation by a severe acute respiratory failure mimicking asthma.

Thymic carcinoma in a child with HIV infection

HIV infection predisposes to cancer during childhood. In addition to the AIDS-defining non-Hodgkin lymphoma (NHL) and Kaposi sarcoma, a range of other lymphoid malignancies and solid tumors have been described. We report the first case of an HIV-positive child with thymic carcinoma in the setting of regressing thymic cysts. The tumor expressed CKIT but failed to respond to imatinab mesylate after a transient response to multiagent chemotherapy. This case extends the spectrum of pediatric malignancy in the setting of HIV and suggests that patients with presumed benign thymic cysts require ongoing surveillance.

Cystic lesions of the mediastinum

Cysts of the mediastinum comprise a relatively diverse group of lesions that include neoplastic and nonneoplastic constituents, the latter of which are largely congenital in nature. Therefore, a grasp of their clinicopathologic characteristics is bolstered by knowledge of which tumors in the chest may undergo cystic change, as well as the embryologic development of the thoracic organs. That information, as well as radiological and pathologic features of these lesions, is discussed in this review.

Pediatric chest ultrasound

Ultrasound examination of the thorax can be quite rewarding in children, because their unique thoracic anatomy provides many acoustic windows into the chest. With only a modest effort, chest ultrasonography can provide many clinically relevant answers, without the radiation exposure from CT, or the need for sedation sometimes required for CT and MR imaging.

Imaging Evaluation of Pediatric Mediastinal Masses

Mediastinal masses in children are a heterogeneous group of asymptomatic to potentially life-threatening congenital, infectious, or neoplastic lesions that can present complex diagnostic and therapeutic dilemmas. This article presents the imaging features of the common mediastinal masses seen in the pediatric population. Classification of the masses is performed according to the traditional mediastinal compartment model, consisting of the anterior, middle, and posterior mediastinum. This scheme facilitates differentiation of the variety of disorders.

Familial thymic cyst

Thymic cysts are rare lesions of the anterior mediastinum or neck. The majority are asymptomatic, and the remainder are associated mainly with symptoms of dysphagia or dyspnea. Diagnosis is difficult before surgery. Cervical thymic cysts are relatively rare; age at presentation ranges from the neonatal period to adulthood, and the most frequent presenting sign is a lateral neck mass. Mediastinal thymic cysts are more common and account for 1% of all mediastinal masses. They tend to occur in the older age group and are usually detected incidentally on chest X-ray film or computed tomography scans. Dysphagia and dyspnea are the main symptoms. We describe two brothers, aged 5 and 8 years, with mediastinal thymic cysts that presented as low cervical masses and review the embryology, diagnosis and management of thymic cysts.

Multilocular thymic cyst associated with mature mediastinal teratoma: a report of 2 cases

Acquired thymic cysts are multilocular and show florid xanthomatous and myofibroblastic inflammation. They usually occur in association with mediastinal neoplasms, systemic autoimmune diseases, or trauma. We describe 2 cases (in a 12-year-old girl and an 11-year-old boy) of acquired thymic cysts occurring in association with cystic teratomas, an association that to our knowledge has not been described previously in the literature.

Prise en charge des kystes thymiques

OBJECTIVE

The thymic cysts are rare tumors of the neck and anterior mediastinum. The management of these patients in our institution is reported. Minimally invasive procedures are discussed.

PATIENTS AND METHODS

Six patients operated in our institution within ten years, with a follow-up of 7.1 +/-3.7 years are studied retrospectively.

RESULTS

There were four women and two men with an average of 39.8 +/-16.5 years. The tumor was found on chest radiograph in four asymptomatic patients, one took medical advice for laryngeal discomfort and another for dysphagia and dyspnea. The tumor was localized in the anterior mediastinum in three cases, in the cervicomediastinal site in two cases and in the cervical site in one case. CT scan was practiced in three patients with a mediastinal tumor and MR imaging in one of them. In patients with cervical or cervicomediastinal tumor, a cervical echography was practiced. All patients were operated on: three by cervicotomy, one by sternotomy, one by partial upper mini-sternotomy and one by right lateral video-assisted mini-thoracotomy. Histology confirmed benign epithelial thymic cyst.

CONCLUSION

There is no specific marker of thymic cysts. Only the surgical management, leads to precise the diagnosis and to treat these tumors. No mortality, no complications or recurrences are reported. The minimally invasive surgery takes an interesting place for thoracic location, to explore and treat these benign mediastinal lesions.

Proliferative and neoplastic disorders in children with acquired immunodeficiency syndrome

Acquired immunodeficiency syndrome (AIDS) is a multisystem disease and, besides infections, various proliferative and neoplastic disorders are seen in cytology, biopsy, and autopsy specimens from infected children. These lesions can be classified into four types: systemic lymphoproliferation, smooth muscle tumors, Kaposi sarcoma (KS), and human papilloma (HPV)-related genital lesions. In addition, isolated cases of multiple miscellaneous tumors have been reported. Proliferative and neoplastic disorders are categorized as lesions of undetermined pathogenesis; however, there are certain factors that are suggested to be related to their pathogenesis. The symptoms related to them may be atypical or difficult to appreciate, and proliferative and neoplastic disorders may clinically mimic an opportunistic infection. The type and site of proliferative and neoplastic disorder also tends to be atypical as compared with those seen in non HIV-infected children. This is a brief but detailed review of these disorders in children with AIDS.

Lymphoid lesions of the head and neck: a model of lymphocyte homing and lymphomagenesis

Lymphoid lesions of the head and neck mainly affect the nasopharynx, nasal and paranasal sinuses, and salivary glands. These three compartments each are affected by a different spectrum of lymphoid malignancies and can serve as model for mechanisms of lymphomagenesis. The type of lymphoma seen reflects the underlying biology and function of the particular site involved. The nasopharynx and Waldeyer's ring are functionally similar to the mucosal associated lymphoid tissue (MALT) of the gastrointestinal tract and are most commonly affected by B-cell lymphomas, with mantle cell lymphoma being a relatively frequent subtype. The most prevalent lymphoid lesion of the salivary gland is lymphoepithelial sialadenitis, associated with Sjögren's syndrome. Lymphoepithelial sialadenitis is a condition in which MALT is acquired in a site not normally containing lymphoid tissue. Patients with Sjögren's syndrome are at increased risk to develop B-cell lymphomas, most commonly MALT lymphomas. The nasal and paranasal sinuses are the prototypical site for the development of extranodal natural killer (NK) /T-cell lymphoma, nasal type. This condition must be distinguished from other conditions causing the clinical picture of lethal midline granuloma, including Wegener's granulomatosis and infectious disorders. Lymphomatoid granulomatosis is common in the lung but is rarely seen in the midline facial structures.

Chemokine gene expression and clonal analysis of B cells in tissues involved by lymphoid interstitial pneumonitis from HIV-infected pediatric patients

Lymphoid interstitial pneumonitis (LIP), a frequent pulmonary complication in HIV-infected pediatric patients, is characterized histologically by marked infiltration of lymphoid cells. We sought to evaluate the nature and pathogenesis of the lymphoid infiltrates and to examine the relationship of LIP to pulmonary MALT lymphoma that has been described in pediatric HIV positive patients. To examine the potential contribution of chemokines and cytokines to the inflammatory cell recruitment in tissues involved by lymphoid interstitial pneumonitis from HIV-infected pediatric patients, RNA was extracted from paraffin-embedded tissues from five lung biopsies in four pediatric HIV-positive patients and from five control, normal lung biopsies in five HIV-negative patients and was analyzed by semiquantitative RT-PCR for the expression of cytokines (TNF-alpha, GM-CSF, IFN-gamma, IL-4, IL-6, IL-10, and IL-18) and chemokines (IP-10, Mig, regulated upon activation, normal T expressed and secreted [RANTES], and MIP1-alpha and beta) after normalization for G3PDH. Expression of IL-18 was increased, as well as expression of IFN-gamma-inducible chemokines IP-10 and Mig in LIP tissues compared with controls. RANTES and MIP1-alpha and -beta were also increased in pediatric LIP lesions compared with controls. In contrast, expression of TNF-alpha, GM-CSF, IL-10, and IL-6 was variable in LIP tissues and controls. In addition, clonality of the B-cell population was evaluated by VDJ-PCR. A polyclonal B-cell population was shown in all five biopsies from five patients with LIP; and in one patient with concurrent LIP and MALT lymphoma, a band of increased intensity was observed in the LIP biopsy that was identical in size to the monoclonal band in the concurrent MALT lymphoma biopsy. These results provide evidence of high-level expression of certain chemokines in lymphoid interstitial pneumonitis tissues and suggest that chemokines and cytokines may play an important role in the recruitment of inflammatory cell infiltrates into these tissues. In addition, LIP may represent an early stage of MALT lymphoma or an immunologic response to a chronic antigenic stimulus that may provide a milieu or microenvironment for the evolution of a monoclonal B-cell population.

Clinical management of anterior mediastinal tumors in children

The majority of anterior mediastinal tumors in children are malignant. The most common tumors in this location are lymphomas, germ cell tumors, and thymic masses. Most require an operation, either a biopsy or a resection, for cure. Because of their size and location, patients with these masses are at significant risk for cardiopulmonary complications when general anesthesia is administered. Of the many clinical, functional, and radiologic criteria used to identify the children at greatest risk for anesthetic complications, the peak expiratory flow rate (PEFR) and the tracheal cross-section area seem to be the most reliable. General anesthesia should not be administered to children if the PEFR and a tracheal cross section area are both less than 50% of predicted values. If both are greater than 50% of predicted values, general anesthesia can be administered safely. An algorithm is proposed for the preoperative evaluation and management of children with anterior mediastinal tumors.

HIV-associated malignancies in children

The exact incidence of malignancies in HIV-infected children is not clear; however, an excess of non-Hodgkin's lymphomas (NHLs) and soft tissue tumors (leiomyosarcomas) is evident. The spectrum of diseases is slightly different in children compared to adults. For example, Kaposi's sarcoma (KS), although common in HIV-infected adults, is rare in children in industrialized countries. Preliminary results with brief, dose-intensive chemotherapeutic regimens have been encouraging. Such regimens may be complicated, however, by multiple HIV-associated organ dysfunctions, drug interactions, and infectious complications secondary to severe immunosuppression.

Germ cell, mesenchymal, and thymic tumors of the mediastinum

Germ cell, mesenchymal, and thymic tumors of the mediastinum are an uncommon and heterogeneous group of neoplasms. Together they account for less than 25% of mediastinal tumors in childhood. The majority of these tumors are found in the anterior and superior mediastinum, but germ cell tumors and mesenchymal tumors may be located in all compartments. They share a broad range of histological subtypes and clinical behavior, tendency to be large in size, and a requirement for complete surgical excision as the major requirement for successful therapy.

Cancers in human immunodeficiency virus-infected children

Although the exact incidence of cancers in human immunodeficiency virus (HIV)-infected children is not clear, an excess of non-Hodgkin's lymphomas and soft tissue tumors as well as a multitude of otherwise rare tumors in childhood, such as cervical, thyroid, or pulmonary carcinoma, has been reported. In contrast to the findings in HIV-infected adults, Kaposi's sarcoma is rare in children in industrialized countries but not in children living in the sub-Saharan area. Treatment of the neoplastic disease is often complicated by multiple HIV-associated organ dysfunctions as well as drug interactions and infectious complications secondary to severe immunosuppression. Nonetheless, preliminary results with dose-intensive, but brief, chemotherapeutic regimens have been encouraging, and HIV-infected children who develop cancer are likely to benefit from aggressive treatment combined with adequate supportive care. Furthermore, insights gained from the study and treatment of this very challenging group of patients may benefit other immunocompromised hosts as well as increase our understanding of oncogenesis in general.