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A unilocular thymic cyst associated with true thymic hyperplasia: a challenging diagnosis especially in a child.

Mlika M, Gattoufi W, Zribi H, Braham E, Marghli A, El Mezni F - Int Med Case Rep J (2015)

Bottom Line: We report a new case of a mediastinal mass in a 19-year-old patient corresponding microscopically to an association of unilocular thymic cyst and true thymic hyperplasia.Our aim is to highlight the absence of specificity of clinical and radiological findings and the necessity of a thorough sampling of the tumor in order to establish the diagnosis.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology, Abderrahman Mami Hospital, Tunis, Tunisia ; Research Unit UR12SP16, Université Tunis El Manar, Faculté de Médecine de Tunis, Tunis El Manar, Tunisia.

ABSTRACT
We report a new case of a mediastinal mass in a 19-year-old patient corresponding microscopically to an association of unilocular thymic cyst and true thymic hyperplasia. Our aim is to highlight the absence of specificity of clinical and radiological findings and the necessity of a thorough sampling of the tumor in order to establish the diagnosis.

No MeSH data available.


Related in: MedlinePlus

The chest computed tomography showed a large anterior mediastinal cystic mass lateralized to the left side frame evoking a cystic teratoma or a cystic thymoma without aggressive loco-regional signs (arrow).
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f1-imcrj-8-215: The chest computed tomography showed a large anterior mediastinal cystic mass lateralized to the left side frame evoking a cystic teratoma or a cystic thymoma without aggressive loco-regional signs (arrow).

Mentions: A 19-year-old man, without a particular past medical history, presented with a 2-week history of sudden left-sided chest pain associated with dyspnea and fever. The patient’s consent was obtained for this case report. Our institute’s Ethics Committee does not require approvals for this type of report. The physical examination was unremarkable. Pulmonary function, electrocardiogram, bronchoscopy, and coronary angiography did not reveal any abnormality. Posteroanterior and lateral chest radiograph showed a homogeneous left parahilar-sided mass of 6 cm, which was well-demarcated. The chest computed tomography (CT) scan showed a large anterior mediastinal cystic mass lateralized to the left side frame evoking a cystic teratoma or a cystic thymoma without aggressive loco-regional signs (Figure 1). Tumor markers such as serum AFP and HCG levels were within normal levels. A mediastinoscopy was performed. Per-operatory examination showed a cystic mass located in the thymic compartment with extension to the contralateral side. The dissection was impossible because of multiple adhesions. Thus, a lateral thoracotomy was performed in order to completely resect the mass. Frozen section examination showed a fibrous cyst wall with many thymic lobules suggestive of thymoma. A complete thymectomy with resection of the mediastinal fat was performed. Gross examination showed a cystic mass of 7 cm, thin-walled with brownish liquid content (Figure 2). Microscopic examination showed a cyst wall lined by a flattened and unistratified epithelial lining overcoming thymic residues (Figure 3). Many Hassall’s corpuscles – sometimes calcified – were observed. Thymic parenchyma seemed hyperplastic with conservation of the corticomedullary differentiation with the presence of many Hassall’s corpuscles (Figure 3). An immunohistochemical study using the terminal deoxynucleotidyl transferase and cytokeratin antibodies was performed in order to rule out the diagnosis of thymoma. In fact, thymoma is characterized by the presence of two components: an epithelial one assessed by cytokeratin antibody and an immature inflammatory one highlighted by the deoxynucleotidyl antibody. We did not observe lymphoid follicles. Based on the microscopic findings, the diagnosis of cystic thymoma was initially suspected but rapidly ruled out because of the rarity of thymoma at that age. The diagnosis of a unilocular thymic cyst associated with TTH was established. The patient was discharged on the fourth postoperative day after an uneventful recovery.


A unilocular thymic cyst associated with true thymic hyperplasia: a challenging diagnosis especially in a child.

Mlika M, Gattoufi W, Zribi H, Braham E, Marghli A, El Mezni F - Int Med Case Rep J (2015)

The chest computed tomography showed a large anterior mediastinal cystic mass lateralized to the left side frame evoking a cystic teratoma or a cystic thymoma without aggressive loco-regional signs (arrow).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4590429&req=5

f1-imcrj-8-215: The chest computed tomography showed a large anterior mediastinal cystic mass lateralized to the left side frame evoking a cystic teratoma or a cystic thymoma without aggressive loco-regional signs (arrow).
Mentions: A 19-year-old man, without a particular past medical history, presented with a 2-week history of sudden left-sided chest pain associated with dyspnea and fever. The patient’s consent was obtained for this case report. Our institute’s Ethics Committee does not require approvals for this type of report. The physical examination was unremarkable. Pulmonary function, electrocardiogram, bronchoscopy, and coronary angiography did not reveal any abnormality. Posteroanterior and lateral chest radiograph showed a homogeneous left parahilar-sided mass of 6 cm, which was well-demarcated. The chest computed tomography (CT) scan showed a large anterior mediastinal cystic mass lateralized to the left side frame evoking a cystic teratoma or a cystic thymoma without aggressive loco-regional signs (Figure 1). Tumor markers such as serum AFP and HCG levels were within normal levels. A mediastinoscopy was performed. Per-operatory examination showed a cystic mass located in the thymic compartment with extension to the contralateral side. The dissection was impossible because of multiple adhesions. Thus, a lateral thoracotomy was performed in order to completely resect the mass. Frozen section examination showed a fibrous cyst wall with many thymic lobules suggestive of thymoma. A complete thymectomy with resection of the mediastinal fat was performed. Gross examination showed a cystic mass of 7 cm, thin-walled with brownish liquid content (Figure 2). Microscopic examination showed a cyst wall lined by a flattened and unistratified epithelial lining overcoming thymic residues (Figure 3). Many Hassall’s corpuscles – sometimes calcified – were observed. Thymic parenchyma seemed hyperplastic with conservation of the corticomedullary differentiation with the presence of many Hassall’s corpuscles (Figure 3). An immunohistochemical study using the terminal deoxynucleotidyl transferase and cytokeratin antibodies was performed in order to rule out the diagnosis of thymoma. In fact, thymoma is characterized by the presence of two components: an epithelial one assessed by cytokeratin antibody and an immature inflammatory one highlighted by the deoxynucleotidyl antibody. We did not observe lymphoid follicles. Based on the microscopic findings, the diagnosis of cystic thymoma was initially suspected but rapidly ruled out because of the rarity of thymoma at that age. The diagnosis of a unilocular thymic cyst associated with TTH was established. The patient was discharged on the fourth postoperative day after an uneventful recovery.

Bottom Line: We report a new case of a mediastinal mass in a 19-year-old patient corresponding microscopically to an association of unilocular thymic cyst and true thymic hyperplasia.Our aim is to highlight the absence of specificity of clinical and radiological findings and the necessity of a thorough sampling of the tumor in order to establish the diagnosis.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology, Abderrahman Mami Hospital, Tunis, Tunisia ; Research Unit UR12SP16, Université Tunis El Manar, Faculté de Médecine de Tunis, Tunis El Manar, Tunisia.

ABSTRACT
We report a new case of a mediastinal mass in a 19-year-old patient corresponding microscopically to an association of unilocular thymic cyst and true thymic hyperplasia. Our aim is to highlight the absence of specificity of clinical and radiological findings and the necessity of a thorough sampling of the tumor in order to establish the diagnosis.

No MeSH data available.


Related in: MedlinePlus