Introduction

Lipoma is derived from mesodem and is present in any part of the body where adipose tissue is present. ₄ But although the hand contains a considerable amount of fat, palmar lipomas are uncommon ₅₆ and digital lipomas are even rarer.The lipoma mostly presents as a gradually increasing painless mass. ₄ MRI scan helps in correct diagnosis ₄ as the tumour resembles implantation dermoid and ganglion clinically. Reassurance and careful surgical excision avoiding injury to digital neurovascular bundles is the treatment of choice.

Case Report

A 43 years old housewife, right handed, reported with a swelling over the middle phalanx of the right index finger.It was noticed about 1 year back and was painlessly and gradually increasing in size. From about a month , patient had been feeling difficulty in gripping objects and it was this complaint which prompted her to consult a doctor. There was no history of trauma nor did patient remember any episode of having got pricked though she did not rule out any such possibilty while doing routine work at home. There was no other past medical or surgical history of significance.Examination revealed a 2cm x 2cm smooth, non tender swelling over the volar surface of middle phalanx of right index finger.the swelling was soft, non compressible, mobile and the skin over it was normal. The index finger had no neurodeficit or vascular compromise. There was no lymphadenopathy nor was there any other visible/palpable swelling on general physical examination. After clinical examination, the swelling was provisionally diagnosed as an implantation dermoid, lipoma or a ganglion. A plain radiograph revealed features of a soft tissue and MRI scan revealed a well defined soft tissue suggestive of a lipoma anterior to flexor tendons of the involved digit.Blood investigations were within normal limits. Excision of the swelling was done under general anaesthesia with proximal tourniquet control. Magnification was achieved with the help of mabnifyong loupes. The swelling was encapsulated and separated from underelying flexor tendons.The retrieved specimen measured 2.5cms x 2.5cms and histopathological analysis confirmed the diagnosis of lipoma. The patient was symptom free after three months of surgery.

Figure 1

Fig 1: Right index finger with lipoma on volar surface of middle phalanx

MRI scan of same case as in Fig 1 showing lipoma over middle phalanx

Discussion

Lipoma is the commonest tumour of the body ₁₂₃ and it can arise in any part where adipose tissue is present.Upper limb is one of the favoured sites for lipoma but due to unknown reasons , the lipomas are very uncommon over the palm ₅₆ and very rare over the digits in spite rich presence of fat.In his series of 476 lipomas of the upper extremity, Barrile could find only 1 case of palmar lipoma ₆ .Lipoma usually presents as a painless swelling though it may cause mechanical difficulty in griping the objects ₇ as was the case with our patient.Over the digits implantation dermoid is a strong differential diagnosis but MRI scan helps in accurate diagnosis and localisation of the tumour which aids in later dissection ₈ .Complete excision is necessary to prevent recurrence ₇ and special care needs to be taken to prevent damage to adjoining digital neurovascular structures. ₉ Magnification particularly helps in preventing such complications. Recovery is usually uneventful though transient neuropraxias can occur. ₇