MACRODACTYLY

Introduction

Macrodactyly, or digital gigantism, is an extremely rare, nonhereditary, congenital deformity characterized by hyperplasia of one or more digits.1,2 In genuine cases, all physical structures of the affected digit are enlarged.3 The etiology of macrodactyly is not completely clear; it may be related to a neurogenic disorder or due to tumorous overgrowth of a single tissue type in the affected digit.3,4 Individuals with moderate-to-severe macrodactyly may experience pain and reduced range of motion (ROM), which often impairs hand function. Although ongoing observation may be adequate for mild cases with few functional limitations, surgery – including soft tissue debulking, epiphysiodesis, osteotomy, ostectomy, and ray amputation – is often needed for more severe cases.1,2,5

Pathophysiology

  • Proposed mechanisms include:
    • Association with a neurogenic disorder, constituting a component of neurofibromatosis3
    • Disturbance of the growth-limiting factor during development, resulting in a local increase in size3
    • Tumorous overgrowth of a single element of tissue in the digit, as in hemangioma, lymphangioma, or enchondroma4
    • Lipomatous degeneration and disturbance of fetal circulation and local growth promoting/inhibiting factors4
    • Several classification systems have been used to describe macrodactyly
      • True macrodactyly and pseudomacrodactyly7
        • Hamartomatous enlargement of all mesenchymal elements of the fingers (phalanges, tendons, nerves, blood vessels, subcutaneous fat, fingernails, skin coverings), but the adjoining metacarpals are not typically affected3
        • True macrodactyly has been further classified as static or progressive
          • Static: present at birth, and the marked overgrowth enlarges proportionally throughout development
          • Progressive: not as noticeable at birth, but the marked overgrowth enlarges disproportionally faster than the rest of the limb throughout development8
  • Another classification system proposes four types of macrodactyly
    • Type I: comorbid lipofibromatosis of a nerve, and static or progressive subtype
    • Type II: associated with neurofibromatosis
    • Type III: associated with hyperostosis
    • Type IV: associated with hemihypertrophy9

Related Anatomy

  • Macrodactyly encompasses a variety of clinical phenotypes, with the rate, location, and extent of overgrowth differing greatly among patients2
  • One or more digits may be involved, and the affected digits are always adjacent6
  • The index finger is most commonly affected, followed by the long finger, thumb, ring finger, and little finger3

Incidence and Related Conditions

  • Macrodactyly of the hands accounts for ~0.9% of all upper extremity congenital anomalies; it is less common in the feet11
  • Macrodactyly is slightly more common in males than in females (7:5)8
  • Macrodactyly is associated with other syndromes, including proteus, carpal tunnel, Bannayan– Riley–Ruvalcaba, Maffucci, and Klippel–Trenaunay–Weber
  • Macrodactyly is associated with other dactylys, including syndactyly, polydactyly, and clinodactyly
  • Macrodactyly simplex congenita or macromelia
  • Hemihypertrophy
  • Neurofibromatosis or lipofibromatous hamartoma of the median nerve
  • Milroy’s disease or Ollier’s disease
  • Adrenal carcinoma, hepatoblastoma, or Wilm's tumor

Differential Diagnosis

  • Proteus syndrome
  • Arteriovenous malformation (AVM)
  • Congenital lymphangioma
  • Macrodystophia lypomatosa progressive

Exam Findings, Signs and Positive Tests

  • Diagnosis of macrodactyly is based primarily on a physical examination and patient history in most cases
    • Physical exam should consist of palpation and inspection for thick and fatty tissue of the involved digit, as well as impaired ROM and/or instability
  • If macrodactyly is encountered during a fetal scan, a thorough evaluation of all systems with special attention to soft tissues and serial scans for development of additional findings such as hemihypertrophy or signs of fetal hydrops is recommended
    • A detailed family history and examination of family members may also help to diagnose an autosomal dominant syndrome associated with macrodactyly if one is present4
Clinical Presentation Photos and Related Diagrams
  • Macrodactyly
    Macrodactyly
Symptoms
• Enlarged digit(s) with impaired function of involved digit(s) and hand(s).
• Limited ROM
• Pain
• Diminished two-point discrimination
Typical History

The typical patient is a 16-year-old, left-handed boy. As he matured, the boy’s parents noticed that his right index and long fingers were growing abnormally faster than the other digits of his hand. This process of enlargement continued throughout the boy’s development, and eventually the two affected digits increased in size to a point where they dwarfed the other fingers. As the fingers grew, the boy experienced progressively limited ROM, reduced functionality of the affected hand, and occasional pain. These symptoms made it difficult for him to perform many basic daily activities (eg, writing, driving, opening doors), and the parents therefore decided it was time to consider surgery to address his condition.2,10,12

Positive Tests, Exams or Signs
Work-up Options
Treatment Options
Conservative: 
  • In mild cases, where the affected digit is not significantly enlarged and the patient does not experience any major functional limitations or other symptoms, ongoing observation alone may be sufficient
Operative: 
  • Surgical intervention may be necessary in severe and/or progressive cases of macrodactyly; the patient’s age, extent and type of the overgrowth, digit(s) involved, and patient and surgeon preference should all be carefully considered when determining the optimal treatment approach
  • It is crucial to distinguish whether the patient has static or progressive-type macrodactyly as early as possible. Although the treatment principles are the same, patients with progressive macrodactyly can expect to undergo surgery earlier, have a higher number of subsequent procedures, and develop earlier interphalangeal joint arthrosis5
  • Soft tissue debulking
    • One of the simplest procedures for macrodactyly
    • May be recommended if the patient’s digit is circumferentially overgrown but shorter than the parent’s digit
    • Progressive soft tissue enlargement, recurrence, or persistence is an indication for additional debulking2
  • Epiphysiodesis
    • Most commonly performed surgical procedure
    • Typically indicated when a single digit is affected
    • May be combined with debulking if the digit approaches the size of the parent’s digit to halt further longitudinal growth2,5
  • Ostectomy: used to shorten affected digits in cases of continued overgrowth
  • Closing wedge osteotomy: typically indicated if the thumb or multiple digits are involved
  • Ray amputation
    • Should be reserved only for severely enlarged, unsightly, and stiff digits that are nonfunctional1
    • May also be indicated in cases when regrowth, pain, or severe deformity occur after attempted reconstruction2
  • Finger or toe transfer2
    • Microvascular great toe transfer may be considered in cases that indicate a thumb amputation2
  • Arthrodesis
  • Neurolysis10
  • Post-surgical rehabilitation may be necessary and should include soft tissue care and early ROM exercises
Complications
  • Hypertrophic scarring
  • Chronic digital pain
  • Edema
  • Decreased sensation
  • Flexion contracture
  • Hook nail
  • Ungual deformity
  • Stiffness of the interphalangeal joints
  • Loss of range of motion
Outcomes
  • Most patients are concerned with obtaining a normal appearance and function in their affected finger(s) after surgery; however, a “normal” finger cannot be achieved in the majority of cases. Thus, counseling patients and their parents about such expectations is important
  • Expectations should focus on producing an “acceptable” finger, which is possible in the vast majority of cases if a good combination of treatment options are used, even if the condition is progressive and severe10,12
  • Studies have reported highly variable results, mainly due to the heterogeneity of macrodactyly. In general, functional outcomes are often superior to aesthetic outcomes5
Key Educational Points
  • A variety of terms, including megalodactyly, macrodystrophia lipomatosa, macrodactylia fibrolipomatosis, lipomatous overgrowth, or hamartoma, gigantomegaly, local gigantism, and digital gigantism, have been used to describe macrodactyly, highlighting the confusion about the condition’s nomenclature. Congenital macrodactyly is the most appropriate term6
  • Macrodactyly is one of the most difficult congenital hand anomalies to treat. With increased understanding of the disease process, treatment is becoming more proactive and simultaneously more complex5,12
  • Most children with macrodactyly will require more than one procedure, particularly those with the progressive type
  • Sparse information regarding outcomes and the technical challenges of reconstruction may contribute to a recommendation for early amputation, which many patients find to be an unacceptable option2
  • Gene-targeted therapy for macrodactyly is in development5
Practice and CME
References

Cited

  1. Akinci M, Ay S, Erçetin O. Surgical treatment of macrodactyly in older children and adults. J Hand Surg Am 2004;29(6):1010-9. PMID: 15576209
  2. Cerrato F, Eberlin KR, Waters P, et al. Presentation and treatment of macrodactyly in children. J Hand Surg Am 2013;38(11):2112-23. PMID: 24060511
  3. Tuli SM, Khanna NN, Sinha GP. Congenital macrodactyly. Br J Plast Surg 1969[LG1] ;22(3):237-43. PMID: 5387390
  4. Yüksel A, Yagmur H, Kural BS. Prenatal diagnosis of isolated macrodactyly. Ultrasound Obstet Gynecol 2009;33(3):360-2. PMID: 19248001
  5. Gluck JS, Ezaki M. Surgical Treatment of Macrodactyly. J Hand Surg Am 2015;40(7):1461-8. PMID: 26050204
  6. Khanna N, Gupta S, Khanna S, Tripathi F. Macrodactyly. Hand 1975[LG2] ;7(3):215-22. PMID: 1205357
  7. Temtamy SA, McKusick VA. The genetics of hand malformations. Birth Defects Orig Artic Ser 1978;14(3):i-xviii, 1-619. PMID: 215242[LG3] 
  8. Barsky AJ. Macrodactyly. J Bone Joint Surg Am 1967;49(7):1255-66. PMID: 4293291[LG4] 
  9. Upton J. Failure of Differentiation and Overgrowth. In: Mathes SJ (Ed) Plastic surgery, 2nd Ed. Philadelphia: Saunders, 2005, pp 265–322[LG5] .
  10. Hardwicke J, Khan MA, Richards H, et al. Macrodactyly—options and outcomes. J Hand Surg Eur Vol 2013;38(3):297-303. PMID: 22736742
  11. Flatt A. The Care of Congenital Hand Anomalies. 2nd ed. St. Louis, MO: Quality Medical Publishers, Inc; 1994[LG6] .
  12. Lee HJ, Kim PT, Lee SJ, et al. Long-term results of single-stage reduction surgery for the treatment of macrodactyly. J Hand Surg Eur Vol 2016 PMID: 27519716

New Articles

  1. [LG7] Lee HJ, Kim PT, Lee SJ, et al. Long-term results of single-stage reduction surgery for the treatment of macrodactyly. J Hand Surg Eur Vol. 2016 PMID: 27519716
  2. Cerrato F, Eberlin KR, Waters P, et al. Presentation and treatment of macrodactyly in children. J Hand Surg Am 2013;38(11):2112-23. PMID: 24060511[LG8] 

Reviews

  1. Gluck JS, Ezaki M. Surgical Treatment of Macrodactyly. J Hand Surg Am 2015;40(7):1461-8. PMID: 26050204

Classics

  1. Tuli SM, Khanna NN, Sinha GP. Congenital macrodactyly. Br J Plast Surg 1969;22(3):237-43. PMID: 5387390
  2. Barsky AJ. Macrodactyly. J Bone Joint Surg Am 1967;49(7):1255-66. PMID: 4293291

[LG1]Unless the article reports on a historical precedence, please try to avoid using older references, especially given the number that are being cited. J

[LG2]Too old.

[LG3]Too old, and this is not included in your highlighted references, and there is no abstract. The article is 619 pages? Please clarify?

[LG4]Too old, and this is not included in your highlighted references, and there is no abstract. Please clarify?

[LG5]This is not included in your highlighted references.

[LG6]Too old, and this is not included in your highlighted references.

[LG7]Please assign a cited article to the most fitting category.

[LG8]If there are no, newer articles on the topic, I’d put this cited reference here.

BTW, you don’t have to use your cited references in the 3 categories. You can include different articles from the literature.