CASE 131
By: Dr. Nizar Al-Nakshabandi MD, FRCPC
HISTORY: Swelling of the index finger since birth.
What are your findings?
What is the differential diagnosis?
What are the causes?
FINDINGS:
The AP plain radiograph [A] demonstrates lengthened and broadened phalanx of the second and third digits which is also splayed. Increase in subcutaneous fat is suspected.
Axial T1 weighted image [B] demonstrates macrodactyly, and abundant accumulation of fat in the subcutaneous tissue with no capsule.
Coronal T1 weighted fat suppressed images [C] demonstrate homogeneous saturation of the fat with no capsule. No focal tumor is seen.
DIFFERENTIAL DIAGNOSIS:
· Macrodystrophia lipomatosa
· Fibromatous hamartoma of the nerves.
· Neurofibromatosis type I.
· Vascular malformations [hemangioma, or arteriovenous malformation].
· Hemihypertrophy.
DIAGNOSIS:
Macrodystrophia lipomatosa.
PEARLS AND DISCUSSION:
Macrodystrophia lipomatosa is a congenital condition. Loss of function and marked swelling of the part of the limb is the most common symptom patients present with.
On a pathological level, increased deposition of mesenchymal fat is seen with adipose tissue present in between the fibrous network which also involves the bone marrow, nerve sheath and muscles.
It could be associated with syndactyly [which is congenital fusion of 2 or more digits], clinodactyly [which is radial angulation of an interphalangeal joint at the radial ulnar or palmar planes], or polydactyly [which is more than the usual number of digits].
The condition is diagnosed with a plain radiograph which is usually suffice However, MRI will help to distinguish macrodystrophia lipomatosis from other differential diagnosis.
FURTHER READING:
1. Murphey MD, Carroll JF, Flemming DJ et-al. From the archives of the AFIP: benign musculoskeletal lipomatous lesions. Radiographics. 24 (5): 1433-66.
2. Khan RA, Wahab S, Ahmad I et-al. Macrodystrophia lipomatosa: four case reports. Ital J Pediatr. 2010;36 : 69.
