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| IMAGE WINDOW |
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| Year : 2023 | Volume
: 3
| Issue : 2 | Page : 64-65 |
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A rare disease with interesting radiologic findings
Gayathri Nair Karedath1, Bhargavan Pallivalappil2
1 Department of Pulmonary Medicine, Baby Memorial Hospital, Calicut, Kerala, India
2 Department of Medicine, Baby Memorial Hospital, Calicut, Kerala, India
| Date of Submission | 08-Jun-2022 |
| Date of Acceptance | 04-Aug-2022 |
| Date of Web Publication | 02-May-2023 |
Correspondence Address:
Dr. Gayathri Nair Karedath
Department of Pulmonary Medicine, Baby Memorial Hospital, Calicut, Kerala
India
 Source of Support: None, Conflict of Interest: None
DOI: 10.4103/jalh.jalh_17_22
How to cite this article:
Karedath GN, Pallivalappil B. A rare disease with interesting radiologic findings. J Adv Lung Health 2023;3:64-5 |
| Question 1 | |  |
What is the probable diagnosis on evaluating the above images?
- Mediastinal teratoma
- Dermoid cyst
- Thymic cyst
- Tuberculosis.
| Question 2 | | |
Paraneoplastic syndromes in thymoma include all except
- Myasthenia gravis
- Pure red cell aplasia
- Thrombocytosis
- Syndrome of inappropriate antidiuretic hormone (SIADH).
| Answers | | |
Question 1: C
Question 2: C
| Thymic Cyst | | |
Thymic cysts are uncommon lesions of the anterior mediastinum, accounting for 1%–5% of all anterior mediastinal masses. It is an epithelium-lined cyst involving the thymus. They may be unilocular or multilocular and may be congenital or acquired. Congenital cysts are thin walled, having thymic tissue in their lining, and acquired cysts are multilocular and are usually formed as a result of an inflammatory process. Thymic cysts are associated with myasthenia gravis (MG), but MG is rare with multilocular thymic cysts. Thymic cysts are usually asymptomatic and incidentally found after chest imaging for other reasons. Symptoms are more commonly observed in infants and children, in which the cyst enlarges and compresses structures producing related symptoms. Adults may present with nonspecific chest pain, cough, stridor, and/or dyspnea
Thymoma is the most common neoplasm of the anterior mediastinum, accounting for 20%–25% of all mediastinal tumors and 50% of anterior mediastinal masses. The mean age of patients is 52 years. As many as 30%–40% of patients who have thymoma experience symptoms suggestive of MG. An additional 5% have other systemic syndromes, including red cell aplasia, dermatomyositis, systemic lupus erythematosus, Cushing's syndrome, and SIADH.
We present a case of MG secondary to thymic cyst in a 64-year-old male. This patient with no known comorbidities presented with complaints of fluctuating ptosis, intermittent fatigable diplopia, and difficulty in swallowing. Clinically, the patient had features of oculopharyngeal myasthenia, and the diagnosis was confirmed by neostigmine test and acetylcholine receptor antibody. X-ray chest PA and left lateral view showed a rounded opacity with calcified borders in the anterior mediastinum [Figure 1]a and [Figure 1]b. Contrast-enhanced computed tomography chest revealed a 5 cm × 3 cm cystic lesion occupying the anterior mediastinum predominantly on the left side with peripheral rim of calcification [Figure 2]a and [Figure 2]b. | Figure-1: X-ray chest of a 64-year-old male patient. (a) PA view showing a spherical shadow with rim calcification (blue arrows), (b) left lateral view showing the lesion in the anterior mediastinum (white arrow)
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 | Figure-2: Computed tomography thorax-mediastinal window showing (a) cystic shadow with calcified curvilinear border in the anterior mediastinum and (b) densely calcified lesion in the anterior mediastinum with central necrosis
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MG association with thymic cyst is rare. There have been very few cases reported in the literature.[1] MG is usually associated with unilocular thymic cyst and it is extremely rare in multilocular cysts.[1] Thymectomy has been a proven therapy for patients with MG.[2] Since thymic cyst has an association with thymoma,[3] all patients with MG should be offered thymectomy after initial treatment and stabilization. It is also reported that MG rarely may recur after thymectomy.[4]
Monden et al. divided the calcification of mediastinal tumors into dystrophic and metastatic types. Manifestations of dystrophic course of a cyst include its cloudy fluid, thick fibrous wall, inflammatory cells, and remnants of destroyed epithelium as well as calcification. Finally, it is transformed into a sole fibrous tissue without specific epithelium or mesothelium but often with a calcified rim.[5]
Sugimoto et al. reported a case of a 58-year-old man with chronic pericarditis who was found to have a calcified mediastinal mass on a chest X-ray. Chest computed tomography and magnetic resonance imaging showed an anterior mediastinal multilocular tumor with rim calcification. Histological examination revealed that the thymic tissue was present around the cyst wall. The final diagnosis was made as mediastinal cyst with rim calcification.[5] Osaki and Nakagawa have reported a case of multilocular thymic cyst with rim calcification and dense adhesions making surgical removal difficult.[6]
Rare instances where thymic carcinoma develops in a thymic cyst are also reported. In most cases, both thymic carcinoma and thymic cyst are asymptomatic and diagnosed only when these compress juxtaposed mediastinal structures. Thymic carcinoma per se is rarely associated with MG or other immune-mediated systemic diseases.[7]
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
| References | | |
| 1. | Mishra AK, Agarwal SK, Pradhan S, Agarwal A. Association of unilocular thymic cyst and myasthenia gravis. Neurol India 2012;60:103-5.  [ PUBMED] [Full text] |
| 2. | Wolfe GI, Kaminski HJ, Aban IB, Minisman G, Kuo HC, Marx A, et al. Randomized trial of thymectomy in myasthenia gravis. N Engl J Med 2016;375:511-22. |
| 3. | Shen X, Jin Y, Shen L, Sun Y, Chen H, Li Y. Thymoma and thymic carcinoma associated with multilocular thymic cyst: A clinicopathologic analysis of 18 cases. Diagn Pathol 2018;13:41. |
| 4. | Peacey SR, Belchetz PE. Graves' disease: Associated ocular myasthenia gravis and a thymic cyst. J R Soc Med 1993;86:297-8. |
| 5. | Sugimoto S, Misao T, Nakano H, Yamane M. Mediastinal cyst with rim calcification. Jpn J Thorac Cardiovasc Surg 2004;52:261-3. |
| 6. | Osaki T, Nakagawa M. Multilocular mediastinal cyst with rim calcification: Report of a case. Surg Today 2008;38:52-5. |
| 7. | Singhal M, Lal A, Srinivasan R, Duggal R, Khandelwal N. Thymic carcinoma developing in a multilocular thymic cyst. J Thorac Dis 2012;4:512-5. |
[Figure 1], [Figure 2]
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