A Case Report of Proximal Palm Giant Lipoma Leading to Double Nerve Compression, with a Brief Literature Review

Summary:

Lipomas are frequently found as benign neoplasms in humans, mainly in the head, neck, and upper limb regions. Because of their rare occurrence in hands and digits, such cases attract researchers’ attention. A case description of a 28-year-old Saudi male patient is presented with a large-size lipoma at the distal forearm, carpal tunnel, and Guyon canal area, with numbness of the central three digits and grip strength weakness of his left hand. The nature of the lesion was a benign, subcutaneous, multilobulated lipoma, removed surgically to prevent malignant transformation and deterioration in neuropathy.

Benign deposits of adipose tissue constitute almost 16% of total soft tissue tumors, comprising half of the total soft tissue neoplasms and affecting 2% of people, with a diversity of sites of origin in the human body.¹ Lipomas arising from the hand account for a relatively small proportion of just 1%–3.8% of benign hand neoplasms.² These tumors commonly occur between 50 and 70 years of age in obese people, without any gender predisposition.² These tumors are categorized according to size and labeled a giant lesion when measurement exceeds 5 cm³. Only one-fourth of these lesions are manifested by symptomatic pressure on other structures in their vicinity.³ Lipomas may arise from the subcutaneous plane, superficial to the palmer fascia, or deep to it, causing compression of neurovascular structures. Our case study describes a young male patient who presented with a lipoma at the flexor retinaculum region with median and ulnar nerve compression.

CASE PRESENTATION

A 28-year-old Saudi architect, a right-handed man with a body mass index of 25 kg/m², presented to the hand surgery clinic on June 22, 2023, with insidious onset of single, soft tissue swelling on the volar aspect of his left proximal palm for 5 years. The swelling was associated with heaviness, localized dullness, and numbness in his index, middle, and ring fingers for the last 2 years before his presentation. His medical and family history was unremarkable. On local examination, he had a soft, nontender, irregular, mobile, lobulated mass measuring 5.5 × 7 cm, extending from the proximal wrist crease on the flexor aspect to the level of Kaplan cardinal line. The mass was nonadherent to the overlying skin but had limited mobility in the deeper plane; the classical slipping sign was absent. Soft touch was decreased to seven of 10, and two-point discrimination was increased to 6–7 mm on both borders of his left central three digits. Tinnel and Phalen tests were positive for the motor nerves of the left hand. In addition, his grip strength and pinch were also slightly weaker than on the opposite side. However, overall, the left-hand vascularity and capillary refill were reassuring. A magnetic resonance imaging (MRI) study revealed bright T1 signals of a homogenous mass with fatty saturation at the carpal tunnel and Guyon canal region (Fig. 1). No prior nerve study was requested because the symptom started insidiously, and it was clear to us that it was due to mass compression. No nerve study was requested after the procedure because the patient’s symptoms improved dramatically. The patient was booked for an excision biopsy. He underwent surgery under the axillary block and tourniquet control. The mass was approached through a zigzag incision over the transverse retinaculum ligament area (Fig. 2). After dissection through subcutaneous tissue, a distinct encapsulated multilobulated fatty tissue lesion was visualized, which extended to the surrounding subcutaneous plane in an irregular fashion and with a minute, deeper extension through the carpal ligament and the Guyon canal, causing gross compression on the median nerve and flexor tendons (Fig. 3). All compartments of this mass were dissected and removed. The nerves were approached easily because the mass was not strongly adherent to them, although it had a tremendous compression effect. The specimen was sent for histopathologic analysis. Surrounding structures were preserved under vision, and the wound was layer-closed after hemostasis was attained with absorbable sutures. A nonadhesive dressing, sterilized gauze, and a compression bandage covered the surgical site. His sensory-motor symptoms improved within 2–3 weeks of surgery, and the pathology report revealed a benign lipoma without any features of malignant transformation (Fig. 4). The patient was examined at his 6-month clinic visit; he was asymptomatic and free of any clinical features suggestive of nerve compression or tumor recurrence.

Fig. 1.

MRI image of a large lobulated high signal intensity mass on T1 and T2 images noted in palmer aspect of mid hand up to wrist at radio carpal joint, showing complete suppression of fat signal on short tau inversion recovery and T1 fat suppression postcontrast study. Compressive effect on carpal tunnel. No aggressive features noted.

Fig. 2.

Preoperative photograph of the same patient with skin bulging in the anterior-posterior aspect of left hand.

Fig. 3.

Intraoperative photograph of the same patient with gross image of the lipoma in the hand. Image shows the volar aspect of the left hand measuring the length of the lipoma.

Fig. 4.

Hematoxylin and eosin-stained section showing adipocyte nuclei that are small, bland, and often compressed at the periphery of the cell (40×).

DISCUSSION

Among benign soft tissue tumors in humans, lipomas account for 33% of upper limb masses.² Hand and digit lipomas have been reported mainly in case reports; however, the most significant case series on this subject was published by Pertea et al.⁴ In 2002, the World Health Organization put forward an explicit classification describing nine types of mesenchymal tumors, which mainly included lipoma, liposarcoma, and lipomatosis of the nerve.⁵

The rare occurrence of hand and finger lipomas can be attributed to this region’s scarcity of adipose tissue. Few authors consider the female preponderance of this lesion to be due to the presence of excessive fatty tissue compared with men. On the contrary, palm lipomas are found more commonly in men; our case report findings favor the latter. Leffert,⁶ published a case series describing 141 lipomas in 122 patients; 22.69% of these lesions were symptomatic, and 0.965% had neurological symptoms.

Some authors describe a giant lipoma as measuring more than 5 cm in size,³ whereas others define it as a lesion greater than 10 cm.⁷ The most prevalent type of peripheral neuropathy is carpal tunnel syndrome. Dailiana et al⁸ have cited these neoplasms as a significant etiological entity leading to median nerve compression. According to these authors, the lesion arises from the median nerve or other structures in the carpal tunnel.⁸ Unal et al⁹ reported a case of a giant lipoma causing both median and ulnar nerve compression in a 50-year-old woman. In our study, the youngest patient has been reported with the solitary largest giant lipoma, causing simultaneous compression of the median and ulnar nerves.

Clinical examination is supplemented in these cases by radiological and histological investigation to rule out malignancy. Capelastegui et al¹⁰ attributed a specificity of 94% to MRI to diagnose malignant changes in lipomas. An MRI scan has been recommended in the literature for lipomas larger than 5 cm, as it helps to rule out other similar lesions, including liposarcoma, neurofibroma, angiolipoma, and giant cell tumors.¹⁰

The main indications for hand lipoma excision are suspected malignancy, compression of neurovascular structures, functional impairment, and aesthetic demands. Small-size digital lipomas are preferably excised under local anesthesia or wide awake local anesthesia no tourniquet, whereas nonsurgical modalities such as mesotherapy and intralesional injections of phospholipids have also been tried with success. Other options for ablation of lipomas are minimal access surgery (endoscopy) and liposuction, but these procedures are associated with a high recurrence rate. We chose the open excision biopsy option for our case as the lesion was well circumscribed and was surrounded by a definite capsule. Yavari et al² described a 5% rate of lipoma recurrence in their study. In comparison, there are no signs of recurrence in our patient at the 6-month follow-up.

We present this case report with a brief literature review to emphasize the nature of this tumor. In our case, if not managed surgically, permanent nerve damage would occur, and the patient would be affected for the rest of his life.

CONCLUSIONS

In conclusion, the hand is a rare site of benign lipoma occurrence, and it needs special attention due to its potential risks of neurological and vascular structure compression and malignant changes, especially in the case of giant lesions. Open surgical techniques for excision biopsy are the only reliable method to achieve the destruction of neoplasm and minimize the chances of recurrence in the future.

DISCLOSURE

The authors have no financial interest to declare in relation to the content of this article.