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| Discussion |
Case Report:
A 40 -year-old man presented with swelling of the right upper limb since childhood, now complaining of pain since six month s.
Local examination revealed a soft, nontender, non-pulsatile swelling of the of right upper limb mainly involving the thumb, index and middle fingers, thenar aspect of the palm and radial aspect of the forearm. There were no pigmented naevi .Few prominent superficial veins were seen.
Clinical photograph is shown below:
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Fig. 1 |
Fig. 2 |
Frontal and oblique Radiographs of the both hands revealed soft tissue and bony overgrowth involving the lateral three digits, 1st and 2 nd metacarpals, scaphoid, trapezium and trapezoid. There was periarticular osteopenia, joint space reduction and deformities involving the radiocarpal,intercarpals, corpometatarsals,metarso-phalangeals,and interphalangeal joints of the lateral three digits.Splaying with exostoses-like bony overgrowth of the ends of all phalanges of involved digits was seen .On the basis these findings, a provisional diagnosis of macrodystrophica lipomatosa was made.
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Fig. 3 |
Fig. 4 |
Gray scale ultrasound showed a large amount of hetregenous soft tissue with posterior acoustic shadowing. No evidence of abnormal calcifications or abnormal dilated venous channels was noted.
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Fig. 5 |
MRI revealed subcutaneous soft tissue and bony hypertrophy involving the lateral aspect of the forearm, thenar aspect of the palm, thumb, index and middle fingers of the right upper limb.
This soft tissue display T1W and T2W hyperintense signal which suppressed on STIR images s/o fat. Muscles and tendons of the forearm and hand were atrophic.
MRI findings confirmed the diagnosis of macrodystrophica lipomatosis.
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Fig. 7 |
Fig. 8 |
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Fig. 9 |
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Angiogram of the right upper limb was performed to rule out any vascular etiology, which was normal.
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Fig. 10 |
DIAGNOSIS:
Macrodystrophica lipomatosa
Macrodystrophia lipomatosa is characterized by progressive overgrowth of all the mesenchymal elements with predominant involvement of fibrofatty tissues. Major clinical features are gigantism of a digit, hands, feet or whole extremity since birth. Involvement is almost always unilateral, although there may be enlargement of one or more adjacent digits in the same extremity. This congenital abnormality occurs most frequently in the distribution of the median nerve in the upper extremity and in the distribution of the planter nerves in the lower extremity. The characteristic feature of this condition is the anatomical location of the abnormality corresponding closely with the zone of innervations by sclerotome. Associated features are conventional lipomas over other parts of body and numerous bony excrescences resembling small osteochondroma or osteophytes. In long standing cases there may be degenerative changes in adjacent joints.
The most patients present with cosmetic problems. Mechanical complains related to interference with the joint functions and neurovascular bundle compression may occur in the later age.
The most striking pathologic finding is the increase in adipose tissue interspersed in a fine mesh of fibrous tissue, which involves the bone marrow, peniosteum, muscles, nerve sheaths, and subcutaneous tissues .Neural enlargement and irregularity may be prominent (most frequently involving the median nerve in the hand and the plantar nerves in the foot.
The various causes of localized gigantism are classified in congenital and acquired.
Acquired causes like dactilitis, hypervascular tumour, and melhorrheostosis can easily be excluded on the basis of history.
Congenital causes like hemihypertrophy which also involved head and trunk and associated with many other anomalies .Progressive arthropathy is not a feature.
The most difficult differential diagnosis, both radiographically and pathologically, is neurofibromatosis.
The occurrence of multiple subcutaneous nodules, bony abnormalities and local gigantism in both conditions may cause confusion, but the extensive ankylosis of distal joints in macrodystrophia and the presence of “ caif-au-lait “ spots or epithelial fibromata in neurofibromatosis help to differentiate the conditions clinically. In neurofibromatosis the enlarged digits may be bilateral, involvement of one extremity is not invariably contiguous, and the distal phalanges are not always the most severely affected. Radiologically, bone changes in neurofibromatosis have a characteristically “wavy “outline and are often related to the course of an affected nerve.
Hyperemia secondary to tumorous overgrowth of the hemangiomatous and lymphangiomatous elements produces only soft tissue hypertrophy, but the limb, apart from the vascular abnormality and the increased size, is structurally normal.
Ollier’s disease which is characterized by multiple enchondromas can also cause localized gigantism but the distribution of the endochondromas ensures rapid identification of this condition.
Radiologists play a very important role in diagnosing this condition using different imaging modalities.Radiological findings can also be used to confidently differentiate this condition from other simulating conditions. This differentiation is of practical importance as the above mentioned conditions differ in their course, prognosis, complications and treatment.