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Home » Bones » Hand » Macrodactyly


- Discussion:
    - a hamartomatous enlargement of soft tissue & underlying bone;
    - can be static, growing commensurately w/ hand, or progressive, growing faster than the rest of the hand;
    - involvement in the hand is more common than involvement in the foot;
    - "nerve territory-oriented macrodactyly":
           - some authors believe that digital nerves cause disproportionate growth of the finger (and that excision in children will reduce 
                 growth with minimal neurologic sequelae;
           - enlargement of the nerve supply to affected digits that more commonly follow the distribution of the median nerve than that of ulnar nerve;
    - associated conditions:
           - neurofibromatosis: as fat & fibrous tissue are found in peripheral nerves of both dz's;
           - lipofibromatosis
                 - references:
                      - Lipofibroma of the median nerve in the palm and digits of the hand.
                      - Lipofibromatous hamartomas of the median nerve.   
                      - Lipofibromatous hamartoma of nerve.  
           - hemi-hypertrophy;
           - Wilm's tumor, adrenal carcinoma, and hepatoblastoma: the association of hemihypertrophy w/ intra-abdominal tumors is particularly
                   strong with Beckwith-Wiedemann syndrome;
           - macrodactyly simplex congenita:
                   - 10% of cases;
                   - enlargement includes skin, subQ tissue, nerve, joint, and bone (tendons and blood vessels are of normal size);
                   - most often phalanges are involved and metacarpals are spared;
           - macromelia;
           - proteus syndrome;

    - diff dx:
           - AV malformation
           - congenital lymphangioma;
           - macrodystophia lypomatosa progressive:
                   - rare form of localized gigantism characterized by a congenital and progressive overgrowth of all the mesenchymal elements in 
                          digit, with a disproportionate increase in the fibroadipose tissue


- Treatment:
    - staged debulking, dealing with one side of digit or hand at a time, because blood supply to the skin of the enlarged digits is poor;
           - in the first stage, defatting is performed on one side of digit, removing up to 20% of its thickness (convex side of digit is adressed first);
           - in the second stage, perform similar defatting procedure and consider bone shortening;
           - in severe cases, consider removal of an entire phalanx (digit must be stabilized with a K wire, extensor tendon shortened, and flexor tendon left alone);
    - appropriately timed epiphysiodesis of the involved bones is performed during growth;
           - alternatively, later bone resections and fusions can be carried out;
    - thumb reduction has been performed by excising the central third and attaching the two lateral portions of bone side to side;
    - in the report by Bertelli JA, et al., the author used a hemi-Bruner zigzag incision was made on the palmar and dorsal aspects of 
           the ulnar sides of the digit, with incisions aligned to match the zigzags;
           - an en bloc dissection included skin, fatty tissue, neurovascular bunldes, and longitudinal resection of 1/3 of the articular surfaces and 
                  bone (proximal, middle, and distal phalanges);
           - tip of the finger and part of the nail were also removed, which allowed digit shortening;
           - collateral ligament of the proximal IP joint was harvested from the portion of the digit removed;
           - transverse shortening was additionally achieved by resection of the physis of the distal phalanx and the DIP joint;
           - transverse retinacular ligament of the extensor tendon was sutured to the flexor tendon sheath;
           - 6 months later, the patient underwent debulking of the skin on the opposite side (w/ preversation of the NV bundle);

    - Case Example: by Jan Van Der Bauwhede MD

          c 1993-1997 Jan Van Der Bauwhede MD