A 50-year-old man was referred for evaluation of dyspnoea of 18 months’ duration. No history of smoking, but employed in a factory environment where dilute hydrochloric acid is used. Previously diagnosed with Obstructive Sleep Apnoea-Hypopnoea Syndrome (OSAHS), treated with Continuous Positive Airway Pressure (CPAP) with a favourable response.
CT scan shows enlargement and sclerosis of the right seventh rib with a dysplastic aspect over its entire length with ossification almost to the sternocostal junction (Figure 1). Posteriorly, the rib shows slight periosteal irregularity and an image of small fragmented sessile exostosis or with adjacent heterotopic ossification (Figure 4).
Around the rib, there is a diffuse fatty infiltration of the thoracic wall, more prominent in the posterior half of the thorax (6th intercostal space) (Figures 3, 5a, 5b), extending medially and touching the pleura. There is also another area of lipoma, better defined anterolaterally, of lenticular morphology, in the fatty plane between the intercostal muscle and the oblique (Figure 6).
Sequences taken after contrast administration show no obvious enhancement of the lipomatous proliferation.
As no enhancing non-fatty tissue was detected, the associated rib anomaly and the absence of related symptoms, a diagnosis of transthoracic lipomatosis associated with congenital rib anomaly was made. A wait-and-see approach was decided with MRI examinations, which confirmed the stability of the lesion.
Lipomatous lesions are a common group of mostly benign growths derived from adipose tissue [1]. They may present as solitary or multiple masses, deep or superficial. They are seldom seen in the thorax, although they can be found in many locations. Deep lipomas tend to be less circumscribed than subcutaneous lipomas, and their contours are usually determined by the spaces they occupy without infiltrating adjacent structures.
Deep thoracic lipomas can be divided into three groups according to their location:
Exceptionally, they are associated with adjacent bone abnormalities (localised gigantism or malformation). Such cases have been reported, most of them more than 20 years ago [3,4].
The pathogenesis of the association between lipoma and congenital bone anomalies is unclear. The most widely accepted theory is that the nerve is initially irritated by an unknown cause, leading to abnormal trophic influences that alter the normal development of the soft tissues and bones corresponding to that dermatomal level, ultimately resulting in lipomatosis and dysostosis.
Clinically, they present as asymptomatic thoracic masses, preferably postero-lateral. Due to their slow growth, the symptoms are often due to the mass effect: cough, dyspnoea [5], cardiac dysfunction.
Chest x-ray shows a well-defined mass with intra- and extrathoracic components, with a homogeneous fat density and some metaplastic calcification.
Chest CT confirms the fat attenuation of the mass, together with changes in the morphology and size of the vertebra and the rib of the metameres, with irritative hyperostosis of the adjacent costal cortex.
MRI is useful in describing the extent of the lesion and its relationship to adjacent organs, as well as identifying the fatty nature of the lesion. The administration of intravenous contrast media provides information about the enhancing pattern: the less the lesion enhances, the more likely is to be of benign origin.
In all cases, deep lipomas must be differentiated from liposarcoma or other lipomatous malignancies, and the distinction often requires anatomopathological analysis.
The management strategy is not established. If asymptomatic, radiological follow-up may be sufficient, but some authors recommend biopsy or surgical excision due to the possibility of well-defined liposarcoma [6]. Even if they are histologically benign, surgery is sometimes necessary if there are symptoms due to their size or location.
All patient data have been completely anonymised throughout the entire manuscript and related files.
Multifocal transmural thoracic lipomatosis
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Based on the provided 3D CT reconstructions and transverse sections (including CT and MRI sequences), a fat-density or fat-signal mass can be observed in the posterolateral thoracic cavity. Part of its extent lies within the thoracic cage and may extend through the intercostal space into the lateral chest wall. Specifically, the following findings are noted:
Considering the patient’s symptoms (dyspnea lasting 18 months) and the fat-density lesion evident on imaging, along with previous clinical data, the following differential diagnoses are possible:
Because the tumor is located between the chest wall and the thoracic cavity, with changes in adjacent ribs or vertebral bodies, it is prudent to exclude secondary bone lesions or other soft tissue tumors affecting the ribs during the diagnostic process.
Considering the patient’s age (50 years), clinical presentation (chronic dyspnea over 18 months, no smoking history, previously diagnosed and controlled OSAHS), and imaging findings indicating a fat-containing space-occupying lesion, the most likely diagnosis is:
Deep Lipoma of the Chest Wall/Thoracic Cavity (Transmural Lipoma)
To definitively rule out low-grade liposarcoma or other specialized fatty tumors, a tissue biopsy or intraoperative frozen section analysis with final pathological diagnosis may be considered clinically.
Given that the patient has respiratory issues (previous OSAHS and current dyspnea related to chest wall changes), a properly designed exercise regimen during recovery should follow these principles:
This report is based solely on the available imaging and clinical data and is intended for reference only. It does not replace in-person diagnosis or professional medical advice. Please consult a specialist or visit a hospital for a comprehensive evaluation and personalized treatment plan.
Multifocal transmural thoracic lipomatosis
