ORIGINAL PAPER

Beyond the depths: deep-seated lipoma of the upper limb

Chris Yuk Kwan Tang & Margaret Fok & Claire Lee &

Boris Fung

Received: 6 August 2013 /Accepted: 24 September 2013 /Published online: 5 November 2013# Springer-Verlag Berlin Heidelberg 2013

AbstractBackground Deep-seated lipomas are mature fat tissues whichmay occur in intermuscular, intramuscular, or submuscular loca-tions. Unlike benign subcutaneous lipoma, which usually onlygrow on skin surface, deep-seated lipoma generally grow slowlyand may sometimes infiltrate deeply and wrap around nerves.Methods A retrospective review of all patients with deep-seated lipomas of the upper limb, operated on between 2002and 2009 at our center, was carried out. Clinical and radiolog-ical characteristics, treatment, and evolution profile of thesepatients were also evaluated.Results Five patients were identified. The mean age of patientswas 71 years (range 60 to 77 years). The mean follow-up periodwas 2 years and there was no recurrence after the surgery.Conclusions The complicated growing patterns of deep-seated lipoma have brought about difficulties during diagnos-tic and surgical procedures. A marked similarity of physicalcharacteristics between a deep-seated lipoma and other soft-tissue masses can cause several confusions, while a carelessdissection can cause severe damage to nearby nerves.Level of Evidence: Level V, therapeutic study

Keywords Lipoma . Deep-seated . Upper limb

Introduction

Lipomas are the most common soft tissue tumor. They can befound anywhere in the bodywith approximately 15–20% locatedin the head and neck region and the majority of the rest in theshoulder and back [1], but their presentation in the hand is lesscommon. They usually develop as well-circumscribed, encapsu-lated masses that have a doughy feel and are freely mobilebeneath the skin. Lipomas can occur in many locations, most

commonly in the subcutaneous tissues; this kind of benign tumorcreates no problem as it can easily be observed. If treatment isnecessary, it can be removed by liposuction or surgical method.Alternatively, conservative treatment can be used. Lipomas,however, can also be found intramuscularly and intermuscularly.Deep-seated lipomas are those that occur deep to the investingfascia (i.e., subfascial), in contrast to the common superficiallipomas that occur in the subcutaneous tissues [2]. They are oftencharacterized by large sizes and infiltrating growing patterns.These types of lipomas are considered uncommon and thoseinvolving the fingers are very rare, with reported incidence of1 % [1, 3]. The large size increases the possibility of encasementof neurovascular bundle and nerve compression. Extra care istherefore needed during the operating process in order to preventdamaging any nearby nerves from which may then result in lossof hand activity of the patients. It is with this view that weemphasize the need for early marginal surgical removal due topotential infiltration of lipoma.

Material and methods

A retrospective review of all patients with deep-seated lipo-mas of the upper limb, operated on between 2002 and 2009from a regional Hospital in Hong Kong, was carried out.Clinical and radiological characteristics, treatment, and evo-lution profile of these patients were also evaluated.

Results

Five patients were identified. The mean age of patients was71 years (range 60 to 77 years). The mean follow-up periodwas 2 years and there was no recurrence after the surgery.Patients are generally elderly, where fat tends to accumulate,and the risk of malignancy of deep-seated lipoma is rather high.However, clinical examination has its limitations, as it is notcertain whether the lipoma is benign. Therefore, we recommendthe patients to undergo magnetic resonance imaging (MRI)scanning to check the extent and nature of the lipoma.

C. Y. K. Tang (*) :M. Fok :C. Lee :B. FungDepartment of Orthopaedics and Traumatology, Queen MaryHospital, 5/F, Professorial Block, Queen Mary Hospital,Pok Fu Lam, Hong Konge-mail: medic.chris.tang@gmail.com

Eur J Plast Surg (2014) 37:29–32DOI 10.1007/s00238-013-0897-1

Fig. 1 Photograph showing a swelling mass on the left forearm

Fig. 2 Preoperative magnetic resonance imaging showing circumferen-tial mass around the proximal radius

Fig. 3 Deep-seated lipoma over forearm excised, leaving radial nerveand its bifurcation intact

Fig. 4 Deep-seated lipoma over left ring finger

Fig. 5 Intraoperative findings of deep-seated lipoma over left ring finger

Fig. 6 Right palm swelling

Fig. 7 Deep-seated lipoma over the palm

Fig. 8 Intraoperative finding of deep-seated lipoma over the palm

30 Eur J Plast Surg (2014) 37:29–32

Case reports

Case 1, a 71-year-old woman presented with a swelling on herforearm. Clinical examination revealed a large soft tissue masson the proximal forearm. There was posterior interosseous nervepalsy before the operation. Operative findings also showed thatthe posterior interosseous nerve appeared atrophic with the intra-muscular lipoma wrapping around it. The posterior interosseousnerve was released and full recovery of the palsy was obtained3 weeks after operation (Figs. 1, 2, and 3).

Case 2, the patient was a 75-year-old man. His maincomplain was a soft tissue swelling on the left hand. MRIscanning showed a deep swelling over the first web thatextend to the second web. It extends from the volar to dorsalside and extends through the two head of adductor pollicisbrevis and also wrap around the second metacarpal.

Case 3, a 60-year-old woman presented with a soft tissueswelling on the ulnar side of the right wrist. It was non-tenderand MRI showed a wrist lipoma located beneath the flexorcarpi ulnaris tendon and ulnar neurovascular bundle. It mea-sured approximately 6×4 cm. There was a distal extension ofGuyon's canal, and the ulnar artery and nerve were stretcheddue to the size of the lipoma. The artery was still patent and noulnar nerve symptoms were present.

Case 4, a 77-year-old man presented with a soft tissue massin the left ring finger. MRI scanning showed a 4×2.5 cmlipoma with a smooth pseudocapsule which was located inthe ring finger. Operative findings showed that there wasencasement of the digital nerve on the ulnar aspect of the left

ring finger and encasement of digital artery on its ulnar aspect(Figs. 4 and 5).

Case 5, the patient was a 68-year-old woman whose maincomplain was a soft tissue swelling on the right palm. MRIscanning showed an infiltrative lipoma, which extended fromthe second metacarpal to the fifth metacarpal and also encase-ment of the common digital nerve. Owing to the extensive natureof lipoma, the digital nerve had to be mobilized and retracted inorder to remove the lipoma. After the operation, the patientcomplained of pain, numbness, and paresthesia on the four digitsand palm. The patient later on experienced a neuralgic pain.These symptoms lasted for 6 to 9 months. (Figs. 6, 7, and 8).

All lipomas were extirpated surgically by resection. Four lipo-maswere adjacent to the neurovascular bundle (onewith the ulnarnerve, one with median nerve, and two with digital nerves) andneeded careful dissection to avoid injuring nearby neurovascularstructures.One parosteal lipomawas adherent to the bone (radius).None had complications or recurrence and return of sensibilityand resolution of the discomfort were noted in each patient afterthe resection Table 1.

Discussion

Deep-seated lipomas are mature fat tissues which may occurin intermuscular, intramuscular, or subcutaneous locations.They generally grow slowly and may sometimes infiltratedeeply and wrap around nerves. They usually appear as largesize at diagnosis and create pressure on the nerves, particularly

Table 1 Summary of the patient characteristics

No. Age Sex Presentation Size (cm) Site Time Operative findings Histology Complications

1 76 F mass 2*4*9.5 Left proximalforearm

13/6/2002 inHong Kong

Intramuscular lipomawrapping aroundproximal radiusand PIN

Lipoma No

2 75 M mass 5*4*2.8 Left hand firstand secondweb space

21/11/2002 inHong Kong

Intramuscular lipomainvolving first andsecond web spaceof left hand, throughthe two heads ofadductor pollicisbrevious and wraparound second MT

Lipoma No

3 60 F mass 6*4*2 Ulnar side ofright wrist

15/10/2009 inHong Kong

Right wrist lipomabetween flexor carpiulnaris tendon andulnar neurovascularbundle

Lipoma No

4 77 M mass 1.6*1.4*3.6 Left ring finger 29/10/2009 inHong Kong

Encasement on digitalnerve and artery onulnar aspect

Lipoma No

5 68 F mass 6.3*2.4*6.3 right palm 20/8/2009 inHong Kong

Right palm lipomaencasing commondigital nerve

Angiolipoma Neuralgic pain overfour digits andpalm (subsidedafter 6–9 months)

Eur J Plast Surg (2014) 37:29–32 31

if located deeply. The patient will, therefore, experience apainful feeling and a swelling on his upper limb. Decrouy-Duruz recently reported a case of a digital giant lipoma, whereMRI showed a benign polylobulated lipomatous tumor, butthat presented nuclear atypia on conventional histologicalexamination suggestive for an atypical lipoma or well-differentiated liposarcoma, and recommended more aggres-sive surgical excision for giant lipomas [3].

In our series, MRI was used for local staging in all fivecases, as this has been shown to be an accurate diagnostictechnique for patients who present with a palpable mass of thehand and wrist, especially for the elderly. This showed com-parable results with the literature that MRI gave the correctdiagnosis in 94 % of instances in a study of 134 patients [4].

We have altogether collected 12 articles [1, 4–14] related todeep-seated lipoma and 55 clinical cases were reviewed. Allpatients were presented with deep-seated lipoma. Among 55patients, 30 % of them had nerve compression, while 4 % ofthem had recurrence after excision of lipoma. In comparison,our series is relatively smaller. Three out of five patients hadnerve compression, but no recurrence was noted in each of thepatients. In our series, one of our patients had neuralgic painafter the operation, which is a complicated case that is notidentified in the other 12 articles.

This suggests that cases of nerve compression by lipomacan sometimes be very complex. Although the chance ofgetting into such complicated case is rare, extra attentionshould always be put when cases involving compression ofnerves are encountered. Nerve damage due to retraction dur-ing the dissection process may result in nerve pain and finger-tips numbness. Therefore, this stresses the importance ofcarefulness during the operating process so as to prevent anynerves from getting injured which may then result in loss ofhand activity and sensibility.

Unlike infiltrative lipomas, subcutaneous lipomas, even ifthey are giant, only have a low recurrence of around 1 % afterexcision [8]. However, for some deep lipoma that may encasethe neurovascular bundle in complicated locations, somecases were noted to have incomplete previous removal oflipoma and were followed by a recurrence. The prevalenceof local recurrence of deep-seated lipoma has been estimatedat 4–5 %, and it occurs more frequently with deep and infil-trating lipomas. There are always difficulties concerning dis-section of deep-seated lipoma. It may likely cause tractioninjury to the nerve, resulting in neuralgia. Moreover, thepressure effect may lead to nerve palsy, thus an extensileapproach is required to explore the nerve proximally. Theextent of resection is often modified to avoid injuring nearbyimportant neurovascular or muscular tissue, and causing func-tional impairment as resection of large and deep lesions ismore difficult. This compromise between adequate surgicalmargins and functional disability may lead to incompleteresection and a higher local recurrence rate [14].

Lipomas have been identified in all age groups, but inadults, deep-seated lipomas are most commonly discoveredbetween the ages of 30 and 60 [8]; unlike in our series,lipomas were more often discovered in the 70s. This mostprobably suggests the statement that deep-seated lipomas tendto appear in the middle to late decades of life when fat beginsto accumulate to form a lipoma which branches out and wraparound nerves inside the body. Treatment by excision requiresa very extensive and careful dissection in order to sparevessels and nerves that are located nearby. All deep-seatedlipomas are found to have infiltrative property, but variationsmay arise concerning their growing patterns and direction.

This report not only describes the general features of deep-seated lipoma and compares some of the behavioral differ-ences between deep-seated lipomas and subcutaneous lipo-mas, but also points out and stresses that complications anddangers may still arise even though the occurrence of deep-seated lipomas are rare.

Conflict of interest None

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