AJTCCM VOL. 28 NO. 3 2022 129

CORRESPONDENCE: CASES

ymolipoma is a rare benign anterior mediastinal tumour of thymic origin containing both thymic and mature adipose tissues. In most

cases it has a silent course and can grow to large sizes before presenting with respiratory symptoms. We report a case of a giant thymolipoma

in a 4-year-old girl treated at Chris Hani Baragwanath Academic Hospital, South Africa.

Afr J Thoracic Crit Care Med 2022;28(3):129-132. https://doi.org/10.7196/AJTCCM.2022.v28i3.181

Thymolipomas are rare benign anterior

mediastinal tumours consisting of thymic

and fatty tissues, and account for 2 - 9% of

all thymic tumours.[1] These tumours are

slow growing and are usually diagnosed

incidentally in older children and young

adults. Surgical excision is the mainstay of

treatment.[1] We report the case of a young

child with a massive thymolipoma who

underwent successful surgical removal.

Case report

A 4-year-old HIV-uninfected girl was referred

to the paediatric pulmonology clinic at Chris

Hani Baragwanath Academic Hospital, South

Africa (SA), with a 2-year history of chronic

cough and poor weight gain. She had been

treated with repeated courses of antibiotics

for respiratory tract infections, and had also

been started on tuberculosis (TB) therapy

based on the chronic cough and abnormal

ndings on chest radiographs.

At presentation, she was stunted, had

digital clubbing, and had dullness to

percussion on the right side of the chest

with reduced breath sounds. Her white

cell count was raised (20.7 × 109/L) with

predominant lymphocytes (80.9%). The

frontal chest radiograph showed a dense

homogeneous opacification in the right

middle and lower zones, and the le middle

zone (Fig.1). e lateral chest radiograph

showed that the opacication was from the

anterior mediastinum. Bronchoscopy showed

a patent right upper lobe bronchus, but the

right bronchus intermedius was completely

occluded as a result of external compression.

e le upper and lower lobes were normal

in structure with patent bronchi. A chest

computed tomography (CT) scan (Fig. 2)

showed an anterior soft-tissue hypodense

mass on the right with herniation across the

midline to the le hemithorax that displaced

surrounding structures but was not encasing

them. Histological examination of a Tru-

Cut biopsy specimen showed benign thymic

parenchyma with no evidence of neoplastic

inltration.

Sternotomy was performed and the entire

mass was resected. e tumour was initially

removed as a well-encapsulated bilobar mass,

but the mass extended posteriorly into the right

thorax and required some piecemeal resection

(Fig.3). Two large specimens were analysed,

weighing 610 g and 360 g and measuring

170 × 100 × 30 mm and 120× 60 × 20 mm,

respectively. Microscopy revealed thymic

parenchymal tissue mixed with mature adipose

tissue, and no features of cytological atypia.

Numerous Hassall’s corpuscles were also seen.

e nal histopathology report conrmed that

the tumour was a thymolipoma. ere were no

intra- or postoperative complications, and the

patient was discharged.

Discussion

To our knowledge, our patient is the youngest

child to have undergone surgical resection of a

large thymolipoma in SA. ymolipomas are

rare, slow-growing benign mediastinal tumours

that were rst described by Hall in 1949.[2] e

global incidence has been reported as 0.12 per

100 000 cases per year.[3] Thymolipoma has

been linked to various autoimmune diseases,

with myasthenia gravis reported in half of the

cases, but the pathogenesis remains unclear.

Other conditions that are associated

with thymolipoma include red cell

aplasia, Graves’ disease, lichen planus and

hypogammaglobulinaemia.[3] e dierential

diagnoses for a large mediastinal mass include

teratoma, thymoma, lipoma, lipomatosis,

liposarcoma and thymoliposarcoma.

Thymolipomas can occur at any age,

although they are mainly found in young

adults (mean age 33years).[4] However, to our

knowledge only 36 cases have been reported

in the current available English literature.

The youngest patient ever reported was a

6-month-old infant who presented with

respiratory distress due to compression of

adjacent structures.[5]

The chest radiograph can mimic

abnormalities of adjacent structures, such

as pericardial effusion, cardiomegaly,

atelectasis or lung sequestration.[6] Our

patient was initially started on treatment for

TB because of the nonspecic radiographic

findings. Computed tomography and

magnetic resonance imaging are usually

diagnostic. They reveal a fatty mass with

brous septa, which is highly suggestive of

a thymolipoma.[7] However, other dierential

diagnoses are possible, and they include

potentially malignant diseases. Definitive

diagnosis is through histopathological

examination, which should demonstrate

mature large lobules of adipose tissue mixed

with normal thymus containing epithelial

cells, thymic lymphocytes and Hassall’s

corpuscles.[1] According to our literature

Giant thymolipoma in a child: e silent chest mass

S Otido,1 MD; Z Dangor,1 PhD; A Zanini,2 MD; D Harrison,2 MD

1 Department of Paediatrics, Chris Hani Baragwanath Academic Hospital and Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa

2 Department of Paediatric Surgery, Chris Hani Baragwanath Academic Hospital and Faculty of Health Sciences, University of the Witwatersrand, Johannesburg,

South Africa

Corresponding author: S Otido (samotido@gmail.com)

130 AJTCCM VOL. 28 NO. 3 2022

CORRESPONDENCE: CASES

Table1. Summary of a literature review of paediatric thymolipomas (references available as a supplementary le at https://www.samedical.org/le/1873)

Author Age (yrs) Presentation Investigation Biopsy Treatment Approach Invasion Malignancy Complications

Maekawa etal.[S1] 16 Incidental CXR, right bundle-

branch block

CT chest + MRI FNA CT

guided

Total

thymectomy

Sternotomy No No No

Miranda etal.[S2] 4 Recurrent LRTI, CXR CT chest + MRI No Primary

resection

n/d No No No

Sundstrom[S3] 8 Incidental CXR No others No Primary

resection,

partial

thymectomy

oracotomy No No No

Damadoglu etal.[S4] 16 Fatigue + myasthenia gravis CT scan No ymectomy Sternotomy No No No

Daneshbod[S5] 17 Dyspnoea on exertion CXR + CT No ymectomy oracotomy No No n/d

Faerber etal.[S6] 5 Cough, tachypnoea and wheezing

for 2 years

CXR, chest US

+ CT

No Tumour

resection

n/d No No n/d

Furukawa etal.[S7] 3 LRTI, CXR CT chest + MRI No Tumour

resection

oracoscopy No No No

Gregory etal.[S8] 9 Incidental on CXR for asthma CT chest + MRI No ymectomy Sternotomy No No No

Gunnels etal.[S9] 4 Incidental CXR Cardiac

catheterisation

No n/d Sternotomy No No No

Gupta etal.[S10] 11 Chest pain CXR + CT EUS-FNA Tumour

resection

oracotomy No No No

Herrera etal.[S11] 8 Incidental CXR Bronchogram,

aortogram, CT scan

No Tumour

resection

oracotomy No No n/d

Kitano etal.[S12] 6 Bulging thorax CXR + CT + MRI +

angiography

No Tumour

resection

Sternotomy No No n/d

Alizadeh etal.[S13] 6 Persistent cough CXR + CT EUS FNA +

open

Tumour

resection

Sternotomy +

thoracotomy

No No No

Nishimura etal.[S14] 6 Incidental CXR CT chest + MRI FNA Tumour

resection

n/d No No No

Onoda etal.[S15] 2 Stridor CXR + CT + MRI No Tumour

resection

n/d No No No

Otto etal.[S16] 5 Anaemia + recurrent infections

(erythrocyte hypoplasia and

hypogammaglobulinaemia)

CXR n/d n/d n/d n/d No No

Park etal.[S17] 16 n/d CT scan n/d Tumour

resection

Robotic

subxiphoid

n/d No No

Parakh etal.[5] 6 mo Tachypnoea CXR + CT scan US-guided

TruCut

Tumour

resection

oracotomy No No n/d

Patel etal.[S18] 11 Right cervical mass CXR + CT scan Open Tumour

resection

Sternotomy No No No

Ringe etal.[S19] 17 Incidental CXR CXR No Tumour

resection

Sternotomy No No No

(continued)

AJTCCM VOL. 28 NO. 3 2022 131

CORRESPONDENCE: CASES

review, a preoperative biopsy specimen was

obtained in only 6/36 patients (16.2%), 4 via

ne-needle aspiration, 1 open and 1 Tru-Cut.

In our case, a Tru-Cut biopsy revealed that

the tissue was fatty in nature and ruled out

malignant disease. We believe that obtaining

a preoperative diagnosis is important in

planning surgical intervention. Ruling out

Table1. (continued) Summary of a literature review of paediatric thymolipomas (references available as a supplementary le at https://www.samedical.org/le/1873)

Author Age (yrs) Presentation Investigation Biopsy Treatment Approach Invasion Malignancy Complications

Rosado-de-

Christenson etal.[S20] 0 - 19 n/d n/d n/d n/d n/d n/d n/d n/d

Shillitoe and

Goodyear[S21] 7 LRTI, CXR CXR No ymectomy n/d No No No

Andrus and Foot[S22] 13 Dyspnoea n/d n/d n/d n/d n/d n/d n/d

Bigelow and Ehler[S23] 10 Cough n/d n/d n/d n/d n/d n/d n/d

Tan etal.[S24] 4 Asthma, CXR CT scan No Tumour

resection

oracoscopy No No No

CXR = chest radiograph; CT = computed tomography; FNA = ne-needle aspiration; MRI = magnetic resonance imaging; LRTI = lower respiratory tract infection; n/d = not documented in the case report; US = ultrasound; EUS = endoscopic ultrasound.

Fig.3. Anterior sternotomy revealed the well-capsulated mass, which was resected in totality.

Fig.1. (A) Frontal chest radiograph showing right homogeneous opacication in the middle and

lower zones including the le middle zone. (B) Lateral view indicating anterior mediastinal mass

(arrow).

Fig.2. (A) Axial cut mediastinal window computed tomography scan of the chest showing the so-

tissue dense mass on the right, herniating to the le hemithorax (black arrow). e blue arrow shows

the compressed right bronchus. (B) Coronal view showing the compressed right lung (red arrow).

132 AJTCCM VOL. 28 NO. 3 2022

CORRESPONDENCE: CASES

malignancy allows the surgeon to avoid pursuing an aggressive, radical

procedure, and even to consider minimally invasive approaches. e

fact that no recurrence or malignant transformation has been reported

supports limited tumour excision through a minimally invasive

approach.[6]

e denitive treatment for thymolipomas is surgical.[1] Several

surgical approaches have been used, including thoracotomy, video-

assisted thoracoscopy and sternotomy, and the decision depends on

the size and location of the tumour.[1] In our review, the approach was

reported in only 16 cases, with sternotomy being the most commonly

used, followed by thoracotomy. e approach in our case was dictated

by the size of the tumour, as a sternotomy allows good access to the

mediastinum and both hemithoraces, and is usually well tolerated

in children. Published data on the paediatric population reveal no

malignant or surgical complications aer intervention.

Conclusion

Thymolipomas are rare, slow-growing benign neoplasms, mostly

diagnosed incidentally, and should be considered as a dierential

diagnosis when a child presents with an anterior mediastinal mass.

Compression symptoms indicate a tumour of large size. Plain

radiographs can be misleading in some cases, or delay definitive

diagnosis and management. Surgical intervention remains the only

curative measure, and is tolerated well in the paediatric population.

Declaration. None.

Acknowledgements. None.

Author contributions. Equal contributions.

Funding.None.

Conicts of interest.None.

1. Aghajanzadeh M, Asgary MR, Mesbah A, etal. Giant thymolipoma of mediastinum

and neck – initially misdiagnosed as liposarcoma by core needle biopsy. J Fam Med

Prim Care 2018;7(5):1079-1082. https://doi.org/10.4103/jfmpc.jfmpc_228_17

2. Hall GF. A case of thymolipoma with observations on a possible relationship to

intrathoracic lipomata. Br J Surg 1949;36(143):321-324. https://doi.org/10.1002/

bjs.18003614318

3. Othman SA, Alfrayyan OY, Alghamdi ZM, etal. ymolipoma association with

myasthenia gravis: Case report. Am J Case Rep 2020;21:e923989. https://doi.

org/10.12659/ajcr.923989

4. Moran CA, Rosado-de-Christenson M, Suster S. ymolipoma: Clinicopathologic

review of 33 cases. Mod Pathol 1995;8(7):741-744.

5. Parakh A, Singh V, Subramaniam R, Narula MK, Agarwala SK, Shukla S. Giant

thymolipoma in an infant. Paediatr Int Child Health 2014;34(3):230-232. https://doi.

org/10.1179/2046905513Y.0000000108

6. Vaziri M, Rad K. Progressive dyspnea in a 40-year-old man caused by giant

mediastinal thymolipoma. Case Rep Surg 2016;2016:3469395. https://doi.

org/10.1155/2016/3469395

7. Nishino M, Ashiku SK, Kocher ON, urer RL, Boiselle PM, Hatabu H. e thymus:

A comprehensive review. Radiographics 2006;26(2):335-348. https://doi.org/10.1148/

rg.262045213

Accepted 8 July 2022.