Background
Lipoma is the most common of all soft tissue tumours and can involve any part of the body [1,2,3]. It is of mesenchymal origin and composed of adipose tissue. Lipomas are usually asymptomatic. Symptoms can only occur when they are situated in cavities or limited spaces leading to localized pressure symptoms or pain due to stretching of nerves. Lipoma is only defined as “Giant Lipoma” when its size is more than 10 cm or its weight is of more than 1 Kg [2]. Giant lipomas are rarely seen over the chest wall [4,5]. As most of lipomas are asymptomatic, patient usually present late to physicians. Here we report a case of giant lipoma of chest extending into the thorax that developed over a span of 15 years.
Case presentation
A 45 year old male visited out-patients department with a large lump in front of left chest. Apparently, it was extending upward into the neck. It progressively enlarged in a span of last 15 years. The mass was initially slow growing and painless. During last two years, it started growing rapidly. Patient also complained of slight pain in the neck region and dyspnoea. On examination, it was a soft mobile mass in front of left chest extending upward into the neck, posterior to the left clavicle. There was no bruit. Regional lymph nodes were not enlarged. Breath sounds were decreased in the upper part of left chest. On Ultrasound (USG), it was a multi-septate echogenic lesion with sparse vascularity on colour doppler. X Ray chest (PA view) revealed a soft tissue mass occupying middle and upper part of left chest (figure 1). Computed Tomography (CT) scan showed a 145mm × 32mm × 190mm hypodense lesion with few calcifications and septations. In the left chest, it was extending from upper to mid chest cavity. It was abutting mediastinum up to the pulmonary artery and was causing atelectasis of adjacent lung tissue (figure 2). Differential diagnosis included liposarcoma and giant lipoma. A core tissue biopsy was performed showing mature adipose tissue without any malignant cells consistent with lipoma. Surgical excision was planned under general anaesthesia. Per-operatively, mass in front of chest was capsulated and excised. It was in continuation with intra-thoracic part through narrow thoracic inlet. Intra-thoracic part was larger and was therefore removed as piecemeal. After removal of intra-thoracic part a drain was placed in intra-thoracic region. Recovery was unremarkable. Post-operative largest piece of removed tissue measured 190mm × 170mm × 50mm, while small pieces collectively measured 150mm × 160mm × 20mm (figure 3). The Specimen was sent for histopathology. Patient was discharged on 3rd post-operative day with drain in situ. Drain was removed on 6th post-operative day followed by removal of stiches on 10th post-operative day. Final diagnosis on histopathology was “lipomatous tumour with few atypical cells”. Patient remained free of any symptoms. Follow up with Magnetic Resonance Imaging (MRI) chest was planned to exclude remnant/ recurrence, followed by treatment accordingly (Radiotherapy for residual and recurrence).
Discussion
Benign tumours of chest are rare. Lipoma may be seen anywhere in the body and at any age [6]. Lipomas are well circumscribed mesenchymal tumours, originating from adipose tissue. Giant lipomas are rarely reported over the chest wall [6]. Local and global incidence is not exactly known; though incidence of lipoma in soft tissue tumours is about 6% [7]. Most common sites are thigh, shoulder and trunk. Lipomas usually involve subcutaneous tissue. They rarely extend into the deeper tissue as in this case i.e. Intra thoracic extension. Due to slow growth and soft consistency with minimal symptoms, patient usually avoids definite treatment for many years. Patient consults physician, once they become symptomatic i.e. Dyspnoea was the presenting symptom in this particular case. Symptoms and signs are closely related to site and size of the tumour. They may be due to pressure effect on surrounding tissue or stretching for neuronal tissue. In our case presenting complain of dyspnoea was due to pressure effect over left lung. Even psychosomatic symptoms are not uncommon with giant lipomas [7].
Diagnosis is usually clinical. Role of USG, CT scan and MRI is well established in making diagnosis. Tissue biopsy is a confirmatory investigation [8]. We used USG to see composition of tumour. CT scan was done to further characterize the lesion inform of its composition, extensions and involvement of vital viscera. These details are of great help in surgical planning and to avoid any emergency situation, especially in vital areas like thorax. Core tissue biopsy was performed to confirm the diagnosis pre-operatively.
Surgical excision of the lump was the treatment of choice; however, liposuction remained another option. This huge lump was removed surgically under general anaesthesia. Post-operatively largest piece of removed tissue measured 190mm × 170mm × 50mm, while small pieces collectively measured 150mm × 160mm × 20mm, full-filling the criteria of Giant lipoma i.e. more than 10cm by size. Patient’s recovery was uneventful after excision and remained symptoms free.