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Year : 2018  |  Volume : 7  |  Issue : 5  |  Page : 1079-1082  

Giant thymolipoma of mediastinum and neck – initially misdiagnosed as liposarcoma by core needle biopsy

1 Respiratory Diseases and TB Research Center, Razi Hospital, Guilan University of Medical Science, Rasht, Iran
2 Department of Pathology, Guilan University of Medical Sciences, Rasht, Iran
3 Vascular Surgery and Dialysis Research Center, Razi Clinical Research and Development Center, Guilan University Medical Science, Rasht, Iran

Date of Web Publication20-Nov-2018

Correspondence Address:
Dr. Mohammad Reza Asgary
Inflammatory Lung Disease Research Center, School of Medicine, Razi Hospital, Guilan University of Medical Science, Rasht
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/jfmpc.jfmpc_228_17

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Thymolipomas are rare benign tumors, constituting one of the differential diagnoses of an anterior mediastinal mass. These tumors may have an indolent, asymptomatic course, often achieving massive dimensions before presentation. When it is symptomatic, respiratory symptoms predominate. We report a case of thymolipoma in a 30-year-old male complaining of heaviness and constricting type of chest pain and neck swelling of 1-year duration. Computed tomography scan finding revealed a space-occupying lesion in the anterior mediastinum and extend to the right side of the mediastinum, neck, and left hemithorax. A sono-guided core needle biopsy was carried out which identified an atypical cell and was suspicious to liposarcoma. The tumor was completely excised through “posterolateral thoracotomy.” Postoperative histopathological examination confirmed the diagnosis of thymolipoma. This is the second case we have reported from our institution.

Keywords: Anterior mediastinum, liposarcoma, thymolipoma

How to cite this article:
Aghajanzadeh M, Asgary MR, Mesbah A, Hemmati H, Delshad MS, Samidoust P, Hemmati G. Giant thymolipoma of mediastinum and neck – initially misdiagnosed as liposarcoma by core needle biopsy. J Family Med Prim Care 2018;7:1079-82

How to cite this URL:
Aghajanzadeh M, Asgary MR, Mesbah A, Hemmati H, Delshad MS, Samidoust P, Hemmati G. Giant thymolipoma of mediastinum and neck – initially misdiagnosed as liposarcoma by core needle biopsy. J Family Med Prim Care [serial online] 2018 [cited 2021 Mar 1];7:1079-82. Available from: https://www.jfmpc.com/text.asp?2018/7/5/1079/245759

  Introduction Top

Thymolipomas (TLs) are rare anterior mediastinal tumors composed of mature adipose tissue and benign thymic tissue arising from the thymus gland. This tumor accounts for only a small percentage of mediastinal masses.[1],[2] The majority of these tumors are clinically quiescent; however, symptomatic patients may present with dyspnea, tachypnea, chest pain, upper respiratory tract infections, and rarely myasthenia gravis.[3],[4],[5] Diagnosis should be confirmed radiologically during the preoperative work-up, with pathognomonic features demonstrated on both computed tomography (CT) scan and magnetic resonance imaging (MRI) and with fine-needle aspiration biopsy (FNAB).[4],[6],[7],[8],[9] TLs are benign neoplasms for which complete surgical excision is curative.[4] Here we report a case of TL in a 35-year-old male complaining of heaviness and constricting type of chest pain, dyspnea, and neck swelling of 2-year duration.

  Case Report Top

The patient is a 35-year-old male presenting with progressive chest pain, cough, dyspnea, and right side neck swelling for the last 2 years. Symptoms have been increased from the last 2 month. On physical examination, on the right side of the neck a soft tissue mass was palpable. From the past medical history, he had a severe car accident 2 years ago and a chest tube was inserted in the right hemithorax because of hemothorax and laparotomy. Breath sound in the right hemithorax was absent. Chest X Ray showed complete opacification of the right hemithorax. Pulmonary function tests showed a decrease in forced vital capacity (47% predicted) and forced expiratory volume (42% predicted) with a total lung capacity of only 72%. These findings were interpreted as being consistent with mixed obstructive and restrictive lung disease. During his diagnostic evaluation, a CT scan was performed. CT scan revealed a huge mass on the right hemithorax which extended to the left hemithorax and the neck; the mass caused a complete right lung collapse and mediastinal shifting to the left side and compressed the heart. The radiologist's report revealed liposarcoma or teratoma [Figure 1], [Figure 2], [Figure 3]. Hematological and serological investigations including tumor markers (alpha-fetoprotein, lactate dehydrogenase, beta-human chorionic gonadotropin, and alkaline phosphatase) were normal.
Figure 1: Computed tomography scan of the chest

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Figure 2: Anterior mediastinal fatty tissue mass with strands and islands of soft tissue with extension to occupying total right hemithorax and to left hemithorax

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Figure 3: Sagittal CT scan of chest showing a mass to occupying total right hemithorax and extend to left hemithorax with strands and islands of soft fatty tissue

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A sono-guided core needle biopsy was carried out which identified an atypical cell and was suspicious to liposarcoma. A right extensive posterolateral thoracotomy was performed via the fifth intercostal space. A large, encapsulated, vaguely lobulated mass was found within the anterior mediastinum. The mass arose in the anterior mediastinal fat, increasing in size as it extended upward to the right side of the neck and extended to the left hemithorax, compressed the heart, reached its lowest level at the diaphragm, and shifted the mediastinum to the left. The mass occupied approximately 90% of the right and 30% of the left pleural cavity, which resulted in complete collapse of the right lung and partial collapse of the left upper lobe [Figure 1], [Figure 2], [Figure 3], [Figure 4]. After tumor dissection and ligation of the blood vessels, first the right hemithorax and the mediastinal mass were resected completely. For prevention of re-expansion pulmonary edema, we did not re-expand the right lung rapidly. Neck portion of the mass was resected via the mediastinum. The left side mediastinal and pleural portion was resected completely. The weight of the mass was 5000 g [Figure 5] and [Figure 6]. In the cut section, it primarily consisted of mature-appearing adipose tissue with no area of hemorrhage or necrosis. There were no postoperative complications and the patient was discharged on day 5 after surgery. Pathology examination results showed a tumor measuring 31 × 21 × 8 cm, consisting of fatty tissue and thymic parenchyma [Figure 7]. There were also foci of collagenous fibrosis and accumulation of cholesterol crystals. No signs of malignant disease were observed. Final pathologist report revealed TL. The patient remains asymptomatic during the sixth month follow-up.
Figure 4: Axial CT scan of chest showing mass extension to neck

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Figure 5: Weight of Resected specimen (Macroscopic)

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Figure 6: Resected specimen: Thymolipoma

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Figure 7: Resected specimen: Thymolipoma (Microscopic)

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  Discussion Top

TLs are very rare, slow-growing mediastinal tumors, accounting for only 2–9% of all thymus tumors.[9] TLs are characterized by mesodermic (fatty) and endodermic (thymic epithelium) elements.[5] TL is a very rare mediastinal tumor composing mature adipose and thymic tissue arising from the thymus gland. It is a rare and benign mesenchymal tumor of the mediastinum that is often asymptomatic.[4] This tumor accounts for only a small percentage of mediastinal tumors.[5],[7] They are lobulated and well encapsulated, with septal divisions.[7] They consist of large lobules of mature adipose tissue interspersed with small areas of thymic tissue [Figure 8], [Figure 9], [Figure 10].[5] TL usually presents as asymptomatic tumors.[5] When the patient does have symptoms, these are usually due to compression of adjacent structures.[5] In our case, dyspnea and chest wall pain may have been due to pulmonary and mediastinal compression. Occasionally, this benign tumor may be associated with certain autoimmune disorders, such as myasthenia gravis, hypogammaglobulinemia, or red cell aplasia.[5] None of these were observed in our patient. Although the finding of soft fatty tissue within the tumor with no invasion of adjacent structures on imaging studies clearly suggests a diagnosis of TL, it is impossible to make a definitive diagnosis or to even distinguish benign disease from malignancy.[5] Differential diagnosis includes other adipose tumors, such as prominent epicardial fat pad, lipomas, liposarcomas, or thymoliposarcomas.[2] Nevertheless, although radiological signs may be nonspecific, CT and MRI can still offer useful data.[2] The characteristic signs of TL on CT consist of a fatty tissue with strands of white tissue, probably corresponding to the islets of normal thymic components.[5] In T1-weighted MRI, fatty tumor tissue is isointense, and in T2-weighted sequences it is suppressed, while the thymic tissue remains are enhanced.[5] Differential diagnosis includes other adipose tumors such as prominent epicardial fat pad, lipomas, liposarcomas, or thymoliposarcomas.[5] Definitive diagnosis is based on histopathological findings. We must consider whether a preoperative FNAB is really necessary in all patients with radiological suspicion of TL.[6],[7],[8] Heimann et al.[6] published the first description of a TL diagnosed using this technique in 1987. However, the role of FNAB in these cases is controversial.[5],[6] It is not always easy to differentiate between a TL and other fatty mediastinal lesions, such as well-differentiated liposarcoma.[5] Romero-Guadarrama et al.[7] reported a false-positive result on FNAB in a patient with an erroneous diagnosis of well-differentiated liposarcoma.[6],[7],[8] On the other hand, Gupta et al.[8] recently published the case of a child diagnosed from a cytology specimen obtained by endoscopic ultrasound-guided FNA. We decided to perform core needle biopsy in our patient, but would not have ruled out the need for surgery, and after complete surgery of the neck and mediastinal mass, the pathologist report revealed TL.
Figure 8: Pathology of mass

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Figure 9: The lesion is composed of an admixture of mature adipose tissue and microscopically normal thymus admixture of mature adipose tissue and unremarkable thymic tissue

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Figure 10: Mature adipose tissue admixed by normal thymus containing epithelial cells, thymic lymphocytes, and Hassall's corpuscles

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The only curative treatment of TL is surgical excision. This treatment is helpful in reducing symptoms caused by the compression of adjacent structures and autoimmune diseases.[5],[7] Various surgical approaches have been described, including thoracotomy,[2],[4] sternotomy,[5],[6],[10] or video-assisted thoracoscopy.[11] The decision must be tailored to tumor size and site. We used posterolateral thoracotomy and removed all of right side and left side of mediastinum and cervical portion parts of mass.

  Conclusion Top

TL is a very rare benign mediastinal tumor, consisting of thymic and fatty tissues. Preoperative diagnosis is frequently based on CT and MRI findings. The use of FNAB remains controversial but should be kept in mind.[2],[4] Surgical intervention is the only cure and also provides the definitive diagnosis.

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Conflicts of interest

There are no conflicts of interest.

  References Top

Carapinha CP, Wainwright L, Loveland JA. A giant thymolipoma. South African Journal of Child Health 2010;4:20-1.  Back to cited text no. 1
Takeda S, Miyoshi S, Akashi A, Ohta M, Minami M, Okumura M, et al. Clinical spectrum of primary mediastinal tumors: A comparison of adult and pediatric populations at a single Japanese institution. J Surg Oncol 2003;83:24-30.  Back to cited text no. 2
Döngel I, Imamoğlu H, Şahin AF, Yıldırım S, Bayram M. A rare mediastinal tumor: Thymolipomarela. European J General Medicine 2014;Suppl 1:21-3.  Back to cited text no. 3
Aghajanzadeh M, Alavi A, Pourrasouli Z, Aghajanzadeh G, Massahnia S. Giant mediastinal thymolipoma in 35-year-old women. J Cardiovasc Thorac Res 2011;3:67-70.  Back to cited text no. 4
Obeso Carillo GA, García Fontán EM, Cañizares Carretero MÁ. Giant thymolipoma: Case report of an unusual mediastinal tumor. Arch Bronconeumol 2014;50:557-9.  Back to cited text no. 5
Heimann A, Sneige N, Shirkhoda A, DeCaro LF. Fine needle aspiration cytology of thymolipoma. A case report. Acta Cytol 1987;31:335-9.  Back to cited text no. 6
Romero-Guadarrama MB, Durán-Padilla MA, Cruz-Ortíz H, Castro-Gómez L, López-Vancell D, Novelo-Retana V, et al. Diagnosis of thymolipoma with fine needle aspiration biopsy. Report of a case initially misdiagnosed as liposarcoma. Acta Cytol 2004;48:441-6.  Back to cited text no. 7
Gupta R, Verma S, Bansal K, Mohta A. Thymolipoma in child: A case diagnosed by correlation of ultrasound-guided fine needle aspiration (EUS-FNA) cytology and computed tomography with histological confirmation. Cytopathology 2014;25:278-9.  Back to cited text no. 8
Halkos ME, Symbas JD, Symbas PN. Acute respiratory distress caused by massive thymolipoma. South Med J 2004;97:1123-5.  Back to cited text no. 9
Savitt MA, Gao G, Furnary AP, Swanson J, Gately HL, Handy JR, et al. Application of robotic-assisted techniques to the surgical evaluation and treatment of the anterior mediastinum. Ann Thorac Surg 2005;79:450-5.  Back to cited text no. 10
Ferrari G, Paci M, Sgarbi G. Thymolipoma of the anterior mediastinum: Videothoracoscopic removal using a bilateral approach. Thorac Cardiovasc Surg 2006;54:435-7.  Back to cited text no. 11


  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8], [Figure 9], [Figure 10]


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