A basaloid carcinoma with multilocular thymic cyst mimicking a mediastinal teratoma.

This case report details a rare thymic basaloid carcinoma initially misinterpreted as a mediastinal teratoma, underscoring the diagnostic challenges posed by such tumors. A 71-year-old female presented with an asymptomatic anterior mediastinal tumor discovered incidentally during a routine health examination. Surgical intervention, followed by pathological and immunohistochemical analysis including CK-pan, p63, p40, and CD117 molecules, led to a definitive diagnosis of basaloid carcinoma of the thymus. This case highlights the critical importance of differential diagnosis in mediastinal lesions, especially those presenting with multilocular thymic cysts on chest CT. The subxiphoid video-assisted thoracoscopic surgery enabled complete tumor resection with minimal trauma and favorable postoperative outcomes. The patient opted against further radiotherapy or chemotherapy and she has survived for over eight months without recurrence. This case report contributes to the growing understanding of thymic basaloid carcinoma, a rare and potentially aggressive thymic carcinoma subtype. It emphasizes the necessity for precise surgical techniques and enhanced diagnostic acumen among cardiothoracic surgeons and oncologists.

Spindle-cell thymoma colliding with a bronchogenic cyst in a Yorkshire terrier.

An 8-year-old male Yorkshire terrier was presented to the Tufts Veterinary Hospital for evaluation of increased respiratory effort. A mediastinal mass composed of a spindle-cell thymoma within a bronchogenic cyst was diagnosed with computed tomography thoracic imaging, ultrasound-guided fine-needle aspirate biopsy, and histopathologic evaluation after surgical removal. Histologic evaluation showed a multilocular cyst structure as well as a mass characterized by spindle to polygonal thymic epithelial cells. The cyst was characterized by a lining of ciliated pseudostratified respiratory epithelium. To the authors' knowledge, this is the first report of a spindle-cell thymoma being associated with a mediastinal bronchogenic cyst in a dog.

[A spherical abnormality on a chest X-ray]. / Een bolronde afwijking op de longfoto.

A 80-year-old man had spherical abnormality on radiography of the chest. The differential diagnosis includes a tumor, hernia of Morgagni or a pericardial diverticulum. CT-scan demonstrated a pericardial cyst with a diameter of 13 cm. Pericardial cysts are rare and are commonly located at the right cardiophrenic angle.

T1 and T2 Mapping for Characterization of Mediastinal Masses: A Feasibility study.

Purpose: To evaluate the feasibility and usefulness of T1 and T2 mapping in characterization of mediastinal masses. Methods: From August 2019 through December 2021, 47 patients underwent 3.0-T chest MRI with T1 and post-contrast T1 mapping using modified look-locker inversion recovery sequences and T2 mapping using a T2-prepared single-shot shot steady-state free precession technique. Mean native T1, native T2, and post-contrast T1 values were measured by drawing the region of interest in the mediastinal masses, and enhancement index (EI) was calculated using these values. Results: All mapping images were acquired successfully, without significant artifact. There were 25 thymic epithelial tumors (TETs), 3 schwannomas, 6 lymphomas, and 9 thymic cysts, and 4 other cystic tumors. TET, schwannoma, and lymphoma were grouped together as "solid tumor," to be compared with thymic cysts and other tumors ("cystic tumors"). The mean post-contrast T1 mapping (P < .001), native T2 mapping (P < .001), and EI (P < .001) values showed significant difference between these two groups. Among TETs, high risk TETs (thymoma types B2, B3, and thymic carcinoma) showed significantly higher native T2 mapping values (P = .002) than low risk TETs (thymoma types A, B1, and AB). For all measured variables, interrater reliability was good to excellent (intraclass coefficient [ICC]: .869∼.990) and intrarater reliability was excellent (ICC: .911∼.995). Conclusion: The use of T1 and T2 mapping in MRI of mediastinal masses is feasible and may provide additional information in the evaluation of mediastinal masses.

[Lesions of the prevascular mediastinum]. / Läsionen des prävaskulären Mediastinums.

CLINICAL/METHODOLOGICAL ISSUE: Mediastinal masses are a group of heterogenous lesions which may be a coincidental finding or present with symptoms. More than half of mediastinal lesions are located in the prevascular mediastinum. As these tumors are not often encountered in clinical routine, making a diagnosis with a high degree of confidence may seem challenging. STANDARD RADIOLOGICAL METHODS: The latest computed tomography (CT)-based classification of the mediastinal compartments by the International Thymic Malignancy Interest Group (ITMIG) moves away from earlier radiograph-based classification systems and helps to reliably classify tumors based on location, although in some cases the lesion can occupy more than one compartment. PERFORMANCE: Radiology plays an important role in the evaluation of anterior mediastinal lesions. Although in some cases imaging features alone allow a diagnosis to be made; in other cases knowledge of important radiological features and their analysis in the context of patient factors like age and duration of symptoms can help to narrow down the differential diagnosis, avoid unnecessary workup, and guide further steps. PRACTICAL RECOMMENDATIONS: Computed tomography (CT) is central for the characterization of mediastinal masses in clinical routine. In some situations, like in the case of thymic cysts or thymic hyperplasia, magnetic resonance imaging (MRI) can be used as a noninvasive problem-solving tool.

[A case of mediastinal bronchial cyst misdiagnosed as schwannoma: a case report].

A case of mediastinal bronchial cyst misdiagnosed as schwannoma is reported. The patient had no chest pain, dyspnea, cough, sputum and hemoptysis in the past. Chest enhanced CT showed mediastinal mass with clear boundary. The larger cross-section was about 3.9 cm × 3.4 cm, and there was no obvious enhancement. The primary diagnosis was considered as schwannoma, tracheal cyst or esophagus cyst. The mediastinal tumor was resected via cervical approach under general anesthesia. During the operation, it was found that the mass was located in the middle and upper mediastinum, with diameter of about 4 cm and a smooth surface, containing gelatinous cystic fluid and adhered to the esophagus and trachea. Postoperative pathological diagnosis was bronchogenic cyst. The patient recovered well after the operation, and has not recurred since follow-up.

Special Computed Tomography Imaging Features of Thymic Cyst.

Objective: To explore the features and diagnostic value of computed tomography (CT) imaging in cases of thymic cysts. Methods: A total of 24 cases of the thymic cysts (confirmed by postoperative pathology) were retrospectively analyzed. The location, morphology, and density of the thymic cysts were summarized, and the changes in CT value of the region of interest (ROI) in the thymic cysts between noncontrast enhanced and enhanced chest scans were compared and classified. Results: The average long-axis dimension was 17.50 ± 6.00 mm, the CT value range across the 24 cases was 5-81 HU, and the average CT value of the noncontrast enhanced scans was 39.75 ± 20.66 HU. The CT value in the noncontrast enhanced scan was >20 HU in 79% of the sample cases. The CT value in the ROI of the thymic cysts under enhanced scan showed a significant decrease in 15 cases, a significant increase in 5 cases, and an insignificant change in 4 cases. Conclusion: The CT values of the thymic cysts in the enhanced scans were generally lower than in the noncontrast enhanced scans, which might be a valuable finding for thymic cysts diagnosis.

[Spontaneous resolution of pericardial cyst: a complex case report]. / Scomparsa spontanea di cisti pericardica: descrizione di un caso clinico intricato.

Pericardial cysts are rare mediastinal abnormalities, generally benign, discovered most often incidentally in the course of diagnostic investigations involving the cardiac profile. They have an incidence of 1 case in 100 000 and are mostly located at the right cardiophrenic angle. Spontaneous resolution of cysts is even rarer. We describe an intricate case report in which the cyst was discovered incidentally and was no longer detected at cardiac magnetic resonance performed 7 years after the first diagnosis. The presence of an asymptomatic pericardial cyst should be regularly followed up over time for the potential risks of complications related to its growth but also because over time, although rarely, it may no longer be detected as in the case presented.

Mediastinal cysts : a 52-case retrospective study.

INTRODUCTION: mediastinal cysts are rare lesions developed from mediastinal structures. They may be acquired like thoracic duct cysts or lymphangiomas or congenital like the bronchogenic cysts, enteric cysts or celomic cysts. These cysts are rare and may cause diagnostic challenges. AIM: To assess the major characteristics of these cysts based on a single institution experience. METHODS: the authors performed a descriptive, retrospective study from January 2009 to March 2020 in a single institution. Cystic lesions taking birth from the mediastinum for which gross features, microscopic features were available were included. RESULTS: this study contained 52 mediastinal cysts that were completely resected and no patient presented complications after the surgical resection. The bronchogenic cysts were the most frequent and represented 57.69% of all lesions. Thymic cysts and pericardial cysts represented respectively 40.38% and 1.92% of the cases. The positive diagnosis was based on the microscopic exam. The final diagnosis was concordant with the radiologic findings in 15 cases reaching a rate of 28%. CONCLUSION: the diagnosis of mediastinal cysts is based on the microscopic analysis of the cystic wall. Pericardial cysts may be suspected based on their characteristic location in the cardiophrenic angle, thymic cyst may be evoked based on their location in the thymic region and bronchogenic cysts are mainly located in the middle mediastinum. Inspite of these most frequent locations, the cysts may be located in any part of the mediastinum and may be difficult to diagnose when the key diagnostic features are absent.

Clinical practices for non-neoplastic thymic lesions: Results from a multidisciplinary cohort.

BACKGROUND: Non-neoplastic thymic lesions are uncommon findings that corresponds to multiple histological and clinical entities that may be difficult to differentiate from thymic malignancies. In this study, our main objective was to describe the clinical, imaging and pathological characteristics of non-neoplastic thymic lesions in a large cohort of patients. We also aimed at understanding the key factors that led to a decision to surgically resect those lesions. METHODS AND MATERIALS: This is an observational, retrospective study. We enrolled both patients with non-neoplastic thymic lesions - normal thymus, thymic lymphoid/non-lymphoid hyperplasia, and thymic cysts - that had been pathologically-confirmed after surgical resection - , and patients with a thymic lesion that was never operated, based on imaging follow-up. RESULTS: A total of 128 patients were included, 88 of whom underwent surgical resection of the lesion (69%), and 40 patients (31%) had follow-up without surgery. Discovery of the lesion was incidental in 69 (54%) cases; thoracic magnetic resonance imaging was performed in 33 (26%) cases, 85% of which showed apparent decrease in the lesion signal intensity in phase opposition at chemical shift sequences. In the 88 operated patients, there were 34 (39%) normal thymuses, 29 (33%) lymphoid hyperplasias, 6 (7%) non-lymphoid thymic hyperplasias, and 19 (22%) thymic cysts. In the 40 non-operated patients, a major driver for the decision of follow-up was the decrease in the lesion signal intensity in phase opposition at chemical shift sequences, observed in 68% of cases; imaging follow-up of these lesions showed sustained regression in the majority of the cases. CONCLUSIONS: The management of benign thymic lesions requires multidisciplinary assessment. A strategy that integrates clinical and imaging features, including chemical-shift sequences at magnetic resonance imaging, as well as follow-up, allows a better selection of the patients for surgery.

Thymic Seminoma with Regressive Changes Obscured by Granulomatous Reaction.

Primary thymic seminoma is an exceedingly rare tumour. There are few case reports about mediastinal thymic seminoma accompanied by secondary changes. We report a case of a 29-year male admitted to our hospital because of chest pain and dyspnea for 8 months. Computed tomography of the thorax revealed hypodense, solid masses showing calcification and cystic degeneration in the anterior mediastinum. Histopathological examination of the resected specimen revealed a diagnosis of thymic seminoma with regressive and reactive changes. The present case was unique in its presentation as a primary seminoma showing combination of cystic degeneration, follicular hyperplasia, fibrosis, calcification and granulomatous reaction in one case. High level of suspicion is necessary to identify seminomas in a thymic lesion accompanied by secondary changes. Excluding the possibility of metastasis from testicular seminoma is very important before making this diagnosis. Key Words: Thymus, Seminoma, Granuloma, Calcification, Cyst.

Transesophageal endoscopic resection of mediastinal cysts (with video).

BACKGROUND AND AIMS: Primary mediastinal cysts are infrequent lesions derived from a variety of mediastinal organs or structures. Complete surgical resection is the treatment of choice even in asymptomatic patients to prevent severe adverse events (AEs) and to establish the diagnosis. Transesophageal endoscopic resection of benign mediastinal tumors has been proven feasible. The aim of this study was to evaluate the feasibility, safety, and efficacy of transesophageal endoscopic surgery for mediastinal cysts. METHODS: From January 2016 to May 2021, patients with mediastinal cysts who underwent transesophageal endoscopic resection were retrospectively included. Clinicopathologic characteristics, procedure-related parameters, AEs, and follow-up outcomes were analyzed. RESULTS: Ten patients with mediastinal cysts were included in this study. The mean cyst size was 3.3 ± 1.3 cm. Histopathology revealed 3 bronchogenic cysts (30.0%), 4 esophageal duplication cysts (40.0%), 2 gastroenteric cysts (20.0%), and 1 lymphatic cyst (10.0%). All procedures were performed uneventfully without conversion to traditional surgery. En-bloc resection was achieved in 6 patients (60.0%). Aggressive resection was avoided to prevent damage to the surrounding vital organs. Mean resection time and suture time were 58.0 ± 36.4 minutes and 5.4 ± 1.0 minutes, respectively. No major pneumothorax, bleeding, mucosal injury, or fistula occurred. One patient had a transient febrile episode (>38.5°C). Mean postoperative hospital stay was 2.7 ± .9 days. No residual or recurrent lesions were observed in any patient during a mean follow-up period of 29.8 ± 19.5 months. CONCLUSIONS: Transesophageal endoscopic surgery appears to be a feasible, safe, effective, and much less invasive approach for mediastinal cyst resection. Larger prospective studies are required to fully assess the efficacy and safety of this novel technique.

Cervical Thymic Cyst with parathyroid tissue - a diagnostic conundrum

Cervical thymic cysts are relatively rare benign cystic lesions that tend to be diagnosed clinically as branchial cysts, which usually present as painless, enlarging neck masses. They can occur anywhere along the normal path of descent of thymic primordia from the angle of the mandible to the sternal notch, with mediastinal extension observed in approximately 50% of cases. They are usually seen in the first decade of life on the left side with a male predominance. Here we report a case of a 15-year-old boy who presented to the hospital with left-sided neck swelling for about 2 months. The neck's contrast-enhanced computed tomography (CECT) revealed a large, well-defined cystic swelling in the left neck region, showing peripheral enhancement, seen from the submandibular region to the superior mediastinum extending into the retrosternal region. Direct fine needle aspiration (FNA) was done, which showed a benign lesion with inflammatory and cystic characteristics, leading to the possibility of a branchial cyst. The cyst was completely excised surgically. Histopathology showed a thymic cyst with parathyroid tissue. The presence of thymic tissue with Hassall's corpuscles is essential for the diagnosis. Knowledge of the clinical presentation, cyto-histological findings, and differential diagnosis of cystic cervical lesions in the pediatric population is important to diagnose this rare entity. Hence, though uncommon, when one comes across a cystic cervical region mass in children, a diagnosis of cervical thymic cyst should be kept in mind. Nonetheless, a definitive diagnosis depends on imaging findings as well as intraoperative findings and histopathological examination.

Recurrent thoracic duct cyst of the left supraclavicular fossa: A retrospective study of 6 observational case series and literature review.

ABSTRACT: The transient occlusion of the terminal thoracic duct is a rare disease responsible for renitent supraclavicular cysts. The aim of this study was to describe the clinical characteristics, evolution, and treatment.A retrospective multicenter study and literature review was carried out. The literature search (PubMed) was conducted including data up to 31 December 2020 and PRISMA guidelines were respected.This study identified 6 observational cases between September 2010 and December 2020. The search results indicated a total of 24 articles of which 19 were excluded due to the lack of recurrent swelling or the unavailability of full texts (n = 5). Fourteen patients (8 from literature) mostly reported a noninflammatory, painless renitent mass in the supraclavicular fossa which appeared rapidly over a few hours and disappeared spontaneously over an average of 8 days (range: from about 2 hours to 10 days). Anamnesis indicated a high-fat intake during the preceding days in all cases and 7 from literature found in the Medline databases. Recurrences were noted in 10 patients. Thoracic duct imaging was performed in all cases to detect abnormalities or extrinsic compression as well as to eliminate differential diagnoses.A painless, fluctuating, noninflammatory, and recurrent swelling of the left supraclavicular fossa in patients evoking an intermittent obstruction of the terminal portion of the thoracic duct was identified. A low-fat diet was found as safe and effective treatment.

Myocardial infarction revealing a pleuropericardial cyst: a case report.

Pericardial cysts are a rare entity, accounting for 6-7 percent of all mediastinal masses. They are frequently congenital relating to a failure of fusion of mesenchymal layers forming the pericardial space. Pericardial cysts are considered rare incidental findings, they are mostly asymptomatic and benign, however life-threatening complications may occur. Here we present a case of a silent pericardial cyst that was discovered by chance while performing transthoracic echocardiography (TTE) for a man who was admitted for myocardial infarction.

Uncommon Location of a Giant Pericardial Cyst: A Case Report.

Pericardial cysts (PCs) are uncommon benign congenital anomalies residing in the middle mediastinum. The location of PCs is diverse with 70% of cases in the right cardiophrenic angle, 22% in the left cardiophrenic angle, and 8% in the posterior (as in our case) or superior anterior part of the mediastinum. In 2019, a 54-year-old woman was referred to the emergency department of Imam Khomeini Hospital Complex (Tehran, Iran) suffering from progressive shortness of breath. The chest computed tomography scan showed an unusual giant cystic lesion occupying >50% of the right hemithorax. The cystic lesion was primarily located in the posterior mediastinum. The patient underwent video-assisted thoracoscopic surgery (VATS), and the cyst was completely resected from the mediastinum. During past decades, several cases of PCs have been reported in different age and sex groups. Here, we present a case of a giant pericardial cyst (PC) located in the posterior mediastinum. The cyst was successfully resected using VATS. Only one other study has reported a PC in the posterior mediastinum.

A multilocular thymic cyst associated with mediastinal seminoma: evidence for its medullary epithelial origin highlighted by POU2F3-positive thymic tuft cells and concomitant myoid cell proliferation.

Multilocular thymic cyst (MTC) and germ cell tumors are common diseases that impact the mediastinum. Correctly diagnosing these diseases can be difficult because several other conditions can mimic them. We report a male patient with MTC associated with mediastinal seminoma. A needle biopsy of the mediastinal tumor revealed numerous epithelioid cell granulomas that mimicked sarcoidosis or mycobacterial infection. However, large atypical cells positive for Oct3/4 and KIT were noted between the granulomas; thus, we diagnosed the patient with mediastinal seminoma. The resected tumor, after chemotherapy, consisted of multiple cystic lesions, and a residual germ cell tumor was first considered. However, thymic medulla-specific elements, namely, POU2F3-positive thymic tuft cells and rhabdomyomatous myoid cells accompanying the epithelium, led to the correct diagnosis of MTC. Our case underscores the importance of recognizing the histological features associated with mediastinal seminoma and provides novel findings for MTC pathogenesis, namely, the presence of thymic tuft cells.

Exophytic cavernous hemangioma arising from the right ventricle: Report of a rare case.

Cardiac hemangioma is relatively rare, accounting for approximately 1-3% of all primary heart tumors. This benign tumor may be an incidental lesion, but can also cause arrhythmias, pericardial effusion, congestive heart failure or outflow obstruction. We report a rare case with exophytic cardiac hemangioma arising from the right ventricle. Echocardiography showed an approximately 40 mm round protruding mass on the anterior wall of the right ventricle. Cardiovascular magnetic resonance demonstrated isointense and hyperintense signals on T1- and T2-weighted images, respectively. These imaging studies suggested a pericardial cyst. Perioperative findings indicated a globular, exophytic mass, vascular in nature, arising from the right ventricle. The lesion was resected directly, and the space left by defect in the right ventricular wall was covered with a bovine pericardial patch. Cardiac hemangiomas are generally endoluminal tumors, but we must keep in mind that the differential diagnoses include various pericardial lesions by medical images.

A Giant Thymic Cyst Accompanied by Acute Mediastinitis.

We encountered a rare case of thymic cyst accompanied by mediastinitis. A 39-year-old Japanese male presented with fever and chest pain. The chest CT revealed a mass composed of a lobular cystic lesion with inflammation, suggesting the onset of mediastinitis. A definitive histological diagnosis was not obtained, and we performed a thymectomy. Pathologically, the thymic cyst was accompanied by multiple cavities, mimicking thymic cysts, caused by the inflammatory abscess. The surrounding adipose tissue showed inflammatory cell infiltrations with chronic fibrosis. These findings indicate that clinicians should be aware that thymic cysts may cause severe mediastinitis.