Introduction

Lipoma is a fatty tissue tumor presenting as a painless slowly growing mass which can affect any part of the body rich in adipose tissue. The severity of cases depends on size and site of the mass and on local pressure complications. It varies from patient to patient and even in advanced cases, it is rarely a complex problem.

The aim of presenting this case is to highlight the advanced presentation of this lipoma and to confirm that surgical excision is the gold standard of its management.

Case report

A 59-year-old woman was admitted with a 10 years' history of a painless swelling at the right thigh. The lesion became ulcerative over the past few months with mild pain.

She had no significant medical and surgical history. Examination revealed normal vital signs, chest, heart, abdominal and rectal examinations.

On local examination, a large mass occupying the posterior aspect of the lower two thirds of the right thigh was confirmed. There was an ulcerative lesion at the posteromedial aspect of the mass. The right popliteal artery was difficult to palpate, but the posterior tibial and dorsalis pedis were normal. There was no neuronal abnormality.

Blood tests showed normal blood count, liver function, urea and electrolytes as well as ESR. She had a normal chest and abdominal X-ray. The X-ray of the right thigh showed a soft tissue shadow and normal bone.

Surgical excision was performed and the findings were consistent with a giant lipoma. The wound was closed easily as there was redundant skin because of the size of the mass. The weight of the specimen was 3.2kg.

The patient had an uneventful recovery and was discharged home with a very good condition. Histology of the specimen reported benign lipoma.

Figure 1

Figure 1: lateral preoperative view of giant lipoma

Figure 2

Figure 2: medial preoperative view of giant lipoma

Discussion

Lipoma is the most common soft-tissue tumor, with a wide spectrum of clinical presentations and imaging appearances. Several subtypes are described, ranging from lesions entirely composed of mature adipose tissue to tumors intimately associated with non adipose tissue and to those composed of brown fat [₁].On the other hand, liposarcoma is a relatively common soft tissue malignancy with a wide spectrum of clinical presentations and imaging appearances[₂].

Benign lipomatous lesions are classified into nine distinct diagnoses [₃] (see table one).

Figure 3

Table 1: Classification of benign lipoma

Lipoma can affect any part of the body containing fatty tissue. Rare locations are also reported in the literature such as renal [₄], colonic [₅], retropharyngeal [₆] and mesenterial lipoma [₇]. Presentation is usually as a painless subcutaneous swelling. Other presentations depend on the site and size of the lesion and on local pressure effects.

Diagnosis is usually simple, but sometimes sophisticated investigations may be needed to define the nature of the lesion. Magnetic Resonance Imaging (MRI) is the preferred modality for the evaluation of a soft tissue mass after plain films have been taken [₈]. Not only lipoma, but many benign soft-tissue masses can be diagnosed correctly and confidently with MRI. The prevalence of benign lesions among soft-tissue masses accounts for the relatively high specificity and negative predictive value that can be achieved with MRI for tissue characterization [₉]. Features that suggest malignancy include increased patient age, large lesion size, presence of thick septa, presence of nodular and/or globular or non-adipose mass-like areas, and decreased percentage of fat composition [₁₀].

Figure 4

Figure 3: the excised lipoma

Surgical resection is the treatment of choice for lipoma, because these large tumors may undergo malignant transformation. Even small lipomatous lesions are resected as a day case practice.

For our patient, the main concern was whether we are dealing with a malignant tumor or just a large benign lipoma. It was difficult to decide that on clinical grounds. For such a big mass with ulceration surgical excision was the treatment of choice. The operative and and histological findings were consistent with a benign giant lipoma.

Conclusion

An advanced presentation of benign lipoma may resemble a malignant lesion. Surgical excision is the treatment of choice to relieve the symptoms, to have tissue diagnosis and to prevent malignant transformation.

Correspondence to

Mr. A HUSSAIN, General Surgery Department, Princess Royal University Hospital , Farnborough common, Farnborough, BR6 8ND, Kent, UK E mail:azahrahussain@yahoo.com Tel : 0044-7949393892 Fax: 0044-1689864456