Peer Reviewed


A Neonate With Hemihyperplasia

Alexander K. C. Leung, MD1,2 • Kin Fon Leong, MD3 • Andrew A. H. Leung, BSc4 • Joseph M. Lam, MD5

1Department of Pediatrics, University of Calgary, Calgary, Alberta, Canada
2Alberta Children’s Hospital, Calgary, Alberta, Canada
3Pediatric Institute, Kuala Lumpur General Hospital, Kuala Lumpur, Malaysia
4Faculty of Medicine, St. George’s University, Grenada
5Department of Pediatrics and Department of Dermatology and Skin Sciences, University of British Columbia, Vancouver, British Columbia, Canada

Leung AKC, Leong KF, Leung AAH, Lam JM. A neonate with hemihyperplasia. Consultant. 2021;61(2):30-32. doi:10.25270/con.2020.09.00004

Received June 17, 2020. Accepted June 21, 2020. Published online September 9, 2020. 

The authors report no relevant financial relationships.

Alexander K. C. Leung, MD, #200, 233 16th Ave NW, Calgary, AB T2M 0H5, Canada (


A 1-month-old boy was referred because of asymmetry of the lower extremities, with the left lower extremity larger than the right. The size discrepancy had been first noted at birth. The boy had been born to a healthy 27-year-old primiparous mother at term following an uncomplicated pregnancy and normal vaginal delivery. His birth weight was 3.5 kg, length was 52.5 cm, and head circumference was 35.7 cm. The neonatal course had been uneventful. He was being breastfed and was thriving. The parents were nonconsanguineous, and the family history was negative for asymmetry of body parts or other congenital abnormalities.

Physical examination showed a happy, well-nourished infant boy in no apparent distress. His vital signs were normal (temperature, 37.1 °C; heart rate, 105 beats/min; and respiratory rate, 28 breaths/min). Her weight was 4.3 kg, length was 54.8 cm, and head circumference was 38 cm. There was a marked discrepancy in the size of the lower limbs (Figures 1 and 2). The length of the lower limbs, measured from the anterior superior iliac spine to the tip of the medial malleolus, was 22.8 cm on the left side and 21.2 cm on the right side. The mid-thigh circumference was 28.7 cm on the left and 25.5 cm on the right. The midcalf circumference was 18.8 cm on the left and 17.6 cm on the right. His face, body, and upper limbs were symmetric. There were no dysmorphic features or apparent visceromegaly. The rest of the examination findings were unremarkable.

 Fig 1
Fig 2
Figures 1 and 2. Hemihyperplasia of the left lower limb, anterior view (left) and posterior view (right).

Laboratory investigations showed a normal complete blood cell count, a normal blood glucose level, and a negative serum α-fetoprotein. Cranial ultrasonography and abdominal ultrasonography findings were normal. Results of Doppler ultrasonography and magnetic resonance imaging of the left limb were unremarkable. A diagnosis of isolated hemihyperplasia was made.


Beauty depends on size as well as symmetry.


Hemihyperplasia, also known as hemihypertrophy, is an asymmetric overgrowth of one or more body parts that is more pronounced than what can be accounted for by normal physiologic variation (arbitrarily defined as <5%) and that cannot be attributed to hemiatrophy of the contralateral part.1,2 The discrepancy in size can be seen in the circumference or length of the affected part, or both.1 Hemihyperplasia can occur in isolation or in association with other congenital anomalies or be part of a syndrome.3,4 Patients may also have associated asymmetry in the size of internal organs.5 Given that hemihyperplasia results from an overgrowth of cells rather than an increase in individual cell size, the term hemihyperplasia is more accurately descriptive and preferred.2,5,6 Hemihyperplasia can been classified as simple (segmental) or complex.6,7 Whereas simple hemihyperplasia involves a single limb, complex hemihyperplasia involves half of the body including at least one arm and one leg.8 Involvement of one side of the face is referred to as hemifacial hyperplasia.1,9


Estimates of the incidence of hemihyperplasia vary from 1 in 13,000 to 1 in 86,000 live births.3,8 The true incidence is difficult to determine, because isolated hemihyperplasia can be very subtle and may not be diagnosed on routine physical examinations, especially at birth. A recent international multicenter prospective study involving 10,066 apparently healthy individuals aged 15 to 18 years showed an incidence of 1 in 5000.10 This is not surprising in view of numerous case reports of patients with hemihyperplasia first referred to their pediatricians between 10 and 18 years of age.11 The condition is more commonly seen in girls.1 The right side of the body is more commonly affected.1


The exact cause of hemihyperplasia is not known. In the isolated form, the cause is usually idiopathic and sporadic.7 However, in some patients with hemihyperplasia, an imprinting defect of genes on 11p15.5, loss of maternal methylation of KCNQ1OT1, or hypermethylation of maternal H19 may be causes.12-14 These same genes are involved in the development of Beckwith-Wiedemann syndrome and Wilms tumor.13,14 Abnormal imprinting may lead to the overexpression of paternal growth-promoting genes or the underexpression of maternal growth-inhibitory genes.6,12 This may result in hyperplasia and increased tumor risk.12 A familial occurrence of hemihyperplasia has been described.3 Some of the reported cases had an autosomal dominant mode of inheritance.8 Other causes of hemihyperplasia include chronic hyperemia (eg, arteriovenous fistula, chronic arthritis, chronic synovitis, chronic osteitis), plexiform neurofibroma, giant hemangioma, lymphangiomatosis, lymphedema, lipomatosis, and bone dysplasia.6


A thorough history and physical examination must be performed to document the asymmetric growth of the body parts and to determine whether a child’s hemihyperplasia is truly isolated or whether it is associated with an underlying abnormality or syndrome.

Anomalies that have been reported in association with hemihyperplasia include genitourinary anomalies (cryptorchidism, renal cysts, horseshoe kidneys, hydronephrosis, hydroureters, medullary sponge kidney, renal agenesis), inguinal hernia, hemangioma, lymphangiomatosis, lipomas/lipomatosis, neurofibroma, and unilateral pigmentation.2,7,15-17

Syndromes associated with hemihyperplasia include Beckwith-Wiedemann syndrome (macrosomia, macroglossia, omphalocele, visceromegaly, ear anomalies, neonatal hyperinsulinemic hypoglycemia), Klippel-Trenaunay-Weber syndrome (cutaneous hemangioma, limb overgrowth, varicose veins, arteriovenous malformations), hemihyperplasia-multiple lipomatosis syndrome (hemihyperplasia, subcutaneous lipomatosis), hemi 3 syndrome (hemihyperplasia, hemiareflexia, hemihypesthesia), Proteus syndrome (overgrowth of long bones, scoliosis, lipolymphohemangiomas, subcutaneous tumors, macrocephaly, macrodactyly, thickening of plantar and palmar surfaces, epidermal nevi), McCune-Albright syndrome (café au lait spots with irregularly shaped jagged borders, polyostotic fibrous dysplasia, bone fractures, precocious puberty, endocrinopathies), Hallermann-Streiff syndrome (dyscephaly, bird-face, dwarfism, skin atrophy, hypotrichosis, congenital cataract, microphthalmia), Langer-Giedion syndrome (short stature, bony overgrowth, microscopy, large ears and nose, broad eyebrows, deep-set eyes, broad eyebrows, thin hair, missing teeth), epidermal nevus syndrome (epidermal nevus, ipsilateral hemimegalocephaly, gyral malformation, seizures, intellectual impairment), CLOVES (Congenital Lipomatosis Overgrowth, Vascular malformations, Epidermal nevi, Spinal/Skeletal anomalies, and/or Scoliosis) syndrome, and SOLAMEN (Segmental Overgrowth, Lipomatosis, Arteriovenous Malformation, and Epidermal Nevus) syndrome.1,16,18-25


Complications depend on the underlying cause of the hemihyperplasia and whether the hemihyperplasia is associated with a distinct clinical syndrome. The most significant comorbidity to consider is the development of malignancies.26 In a prospective multicenter study of 168 children with isolated hemihyperplasia, 10 tumors developed in 9 patients over a 10-year period for an estimated incidence of 5.9%.8 In another study of 24 patients with isolated hemihyperplasia, one patient (4.2%) developed Wilms tumor during a 15-year follow-up.27 The incidence of tumors in syndromic hemihyperplasia is considerably higher, up to 10% in one study.28 Malignancies associated with hemihyperplasia include Wilms tumor, hepatoblastoma, adrenal carcinoma, renal cell carcinoma, neuroblastoma, pheochromocytoma, mesenchymoma, leiomyosarcoma of the small bowel, hemangioendothelioma, breast carcinoma, and rhabdomyosarcoma.6,8,29-31 Tumor risk is greatest in the first decade of life; thereafter, it declines to about the same risk as in the general population.12 The average age at the time of tumor detection was 36 months; approximately 95% of the tumors were located in the abdomen.8 Extra-abdominal tumors rarely occur but have been reported in the brain, testis, lung, uterus, breast, and bone marrow.26

Hemihyperplasia of a lower limb can lead to leg-length discrepancy and result in pain, limping, and early degenerative bony changes, as well as cosmetic problems and difficulty in fitting clothing and footwear.6,21 Carpal tunnel syndrome may result if the hemihyperplasia involves an upper limb.32,33


Treatment of hemihyperplasia is symptomatic and can include orthotics and braces. In severe cases, orthopedic surgical intervention may be warranted. Psychosocial support for the child may be considered, because hemihyperplasia can be associated with poor self-esteem and psychological stress.6,22

Continued screening for potential tumors is also an important part of management. Although screening recommendations vary, all focus on early detection of abdominal tumors, because these are most frequently associated with hemihyperplasia.6 Screening can include physical examinations and measurement for elevation of serum α-fetoprotein, serum chorionic gonadotropin, and urinary catecholamines (vanillylmandelic acid and homovanillic acid) every 3 to 4 months until 4 years of age.1,26 Some authors recommend measurement of serum α-fetoprotein as frequently as every 6 weeks until 4 years of age.12 Given that most of the malignancies arise in the abdomen, it has been suggested that abdominal ultrasonography be performed every 3 to 6 months until age 8 years,2,12,34 and that clinical surveillance for other tumors be considered.35 A complete blood cell count and chest radiography every 12 months until age 10 years also have been recommended.25 It is recommended that a complete physical examination be performed at least once every 6 months until growth has been completed.1,2


  1. Jones SM, Rahman RS, Bourgeois DJ III, Steele RW, Halat S. Hemihyperplasia in a 4-month-old. Clin Pediatr (Phila). 2011;50(4):367-371. doi:10.1177/0009922810397337
  2. Ören NC, Vurucu S, Karaman B, Örs F. Renal agenesis in a child with ipsilateral hemihypertrophy. Pediatr Nephrol. 2010;25(9):1751-1754. doi:10.1007/s00467-010-1525-y
  3. Heilstedt HA, Bacino CA. A case of familial isolated hemihyperplasia. BMC Med Genet. 2004;5:1. doi:10.1186/1471-2350-5-1
  4. Maniar S, Azzi K, Iraqi H, El Hassan Garbi M, Chraibi A, Gaouzi A. Idiopathic corporeal hemihypertrophy associated with hemihypertrichosis. Ann Endocrinol (Paris). 2011;72(1):48-52. doi:10.1016/j.ando.2010.06.003
  5. Abraham P. What is the risk of cancer in a child with hemihypertrophy? Arch Dis Child. 2005;90(12):1312-1313. doi:10.1136/adc.2005.082792
  6. Ho J, Leung AKC, Pacaud D. What’s your diagnosis? Isolated hemihyperplasia. Consultant Pediatricians. 2009;8(1):17-19.
  7. da Costa JN, Matias J. Segmental hemihyperplasia-related macrodactyly with congenital renal agenesis: a hand surgeon’s point of view. Arch Plast Surg. 2015;42(5):655-658. doi:10.5999/aps.2015.42.5.655
  8. Hoyme HE, Seaver LH, Jones KL, Procopio F, Crooks W, Feingold M. Isolated hemihyperplasia (hemihypertrophy): report of a prospective multicenter study of the incidence of neoplasia and review. Am J Med Genet. 1998;79(4):274-278.
  9. Nandimath SA, Rajkumar GC, Nayak T, Ashwin DP, Rudresh KB, Prashanth R. Hemifacial hypertrophy: exploring new avenues of treatment modalities. Natl J Maxillofac Surg. 2016;7(1):100-104. doi:10.4103/0975-5950.196123
  10. Vaiman M, Shilco P, Roitblat Y, et al. Screening procedure for hemihypertrophy: preliminary results of international multicenter prospective study. Cent Asian J Glob Health. 2019;8(1):336. doi:10.5195/cajgh.2019.336
  11. van der Velpen I, Schendelaar P, van Pinxteren-Nagler E, Mouës-Vink CM. A 15-year-old girl with an asymmetric hemitruncal fat distribution: hemihyperthrophy or hemiatrophy? Plast Reconstr Surg Glob Open. 2016;4(4):e684. doi:10.1097/GOX.0000000000000653
  12. Rao A, Rothman J, Nichols KE. Genetic testing and tumor surveillance for children with cancer predisposition syndromes. Curr Opin Pediatr. 2008;20(1):1-7. doi:10.1097/MOP.0b013e3282f4249a
  13. Russo S, Calzari L, Mussa A, et al. A multi-method approach to the molecular diagnosis of overt and borderline 11p15.5 defects underlying Silver–Russell and Beckwith–Wiedemann syndromes. Clin Epigenetics. 2016;8:23. doi:10.1186/s13148-016-0183-8. Published correction appears in Clin Epigenetics. 2016;8:40.
  14. Shterenshis M, Roitblat Y, Ilani J, Lumbroso J, Padilla-Raygoza N. The 11p15.5 chromosomal region: when did the instability occur? Med Hypotheses. 2018;121:21-25. doi:10.1016/j.mehy.2018.09.008
  15. Arora MV, Choubey MS, Saikia M, Fotedar S. Congenital hemihyperplasia with hemipigmentation: a rare presentation. J Anaesthesiol Clin Pharmacol. 2015;31(2):253-255. doi:10.4103/0970-9185.155161
  16. Erpolat S, Tekerekoglu B, Sonmez FM. Hemihyperplasia-multiple lipomatosis syndrome associated with hydrocephalus. Genet Couns. 2014;25(3):251-255.
  17. Priyamvada PS, Parameswaran S, Sandeep M, Shankar V, Swaminathan RP. Medullary sponge kidney and isolated hemihyperplasia. Indian J Nephrol. 2014;24(4):243-245. doi:10.4103/0971-4065.133013
  18. Craiglow BG, Ko CJ, Antaya RJ. Two cases of hemihyperplasia-multiple lipomatosis syndrome and review of asymmetric hemihyperplasia syndromes. Pediatr Dermatol. 2014;31(4):507-510. doi:10.1111/pde.12071
  19. Leung AKC, McArthur RG, Ross SA, McMillan DD, Sauve RS. Thyroxine-binding globulin deficiency in Beckwith syndrome. J Pediatr. 1979;95(5 pt 1):752-754. doi:10.1016/s0022-3476(79)80730-1
  20. Leung AKC. Wiedemann-Beckwith syndrome and hypothyroidism. Eur J Pediatr. 1985;144(3):295. doi:10.1007/BF00451969
  21. Leung AKC, Lowry RB, Mitchell I, Martin S, Cooper DM. Klippel-Trenaunay and Sturge-Weber syndrome with extensive Mongolian spots, hypoplastic larynx and subglottic stenosis. Clin Exp Dermatol. 1988;13(2):128-132. doi:10.1111/j.1365-2230.1988.tb00678.x
  22. Leung AKC, Fong JHS, Leong AG. Hemihypertrophy. J R Soc Promot Health. 2002;122(1):24-27. doi:10.1177/146642400212200111
  23. Mallick A, Singh RK, Thapar RK. Hallermann Streiff syndrome: ‘Bird faced’ but not ‘bird brained.’ Med J Armed Forces India. 2018;74(2):193-195. doi:10.1016/j.mjafi.2017.02.005
  24. Mirastschijski U, Altmann S, Lenz-Scharf O, Muschke P, Schneider W. Syndromes with focal overgrowth in infancy: diagnostic approach and surgical treatment. J Plast Surg Hand Surg. 2012;46(1):45-48. doi:10.3109/02844310902957728
  25. Teplick A, Kowalski M, Biegel JA, Nichols KE. Educational paper: screening in cancer predisposition syndromes: guidelines for the general pediatrician. Eur J Pediatr. 2011;170(3):285-294. doi:10.1007/s00431-010-1377-2
  26. Gracia Bouthelier R, Lapunzina P. Follow-up and risk of tumors in overgrowth syndromes. J Pediatr Endocrinol Metab. 2005;18(suppl 1):1227-1235. doi:10.1515/jpem.2005.18.s1.1227
  27. Atik T, Cogulu O, Ozkinay F. Results of fifteen-year follow-up from a single center: findings and risks for tumor development in isolated hemihyperplasia cases. Genet Couns. 2014;25(4):417-421.
  28. Dempsey-Robertson M, Wilkes D, Stall A, Bush P. Incidence of abdominal tumors in syndromic and idiopathic hemihypertrophy/isolated hemihyperplasia. J Pediatr Orthop. 2012;32(3):322-326. doi:10.1097/BPO.0b013e3182471b04
  29. Amini Z, Babovic-Vuksanovic D, Lteif A. Bilateral pheochromocytomas in a child who had hemihypertrophy and alteration in the VHL gene. J Pediatr Endocrinol Metab. 2013;26(3-4):369-372. doi:10.1515/jpem-2012-0255
  30. Alipour S. Breast cancer management in a case of hemihypertrophy/lymphedema. Del Med J. 2013;85(3):81-83.
  31. Kalish JM, Conlin LK, Mostoufi-Moab S, et al. Bilateral pheochromocytomas, hemihyperplasia, and subtle somatic mosaicism: the importance of detecting low-level uniparental disomy. Am J Med Genet A. 2013;161A(5):993-1001. doi:10.1002/ajmg.a.35831
  32. Leclère FMP, Unglaub F, Gohritz A, Hahn P. Carpal tunnel syndrome caused by supernumerous lumbrical muscle in hemihyperplasia of the upper extremity. Neurochirurgie. 2012;58(5):309-313. doi:10.1016/j.neuchi.2012.05.002
  33. Shimoe T, Taniguchi Y, Yoshida M. Carpal tunnel syndrome in patient with hemihypertrophy: case report. Hand Surg. 2013;18(3):411-412. doi:10.1142/S021881041372026X
  34. Clericuzio CL, Martin RA. Diagnostic criteria and tumor screening for individuals with isolated hemihyperplasia. Genet Med. 2009;11(3):220-222. doi:10.1097/GIM.0b013e31819436cf
  35. Guala A, Pastore G, Fagioli F, Scappaticci S, Danesino C. Hemihypertrophy and myelodysplasia. Pediatr Blood Cancer. 2004;43(6):707-708. doi:10.1002/pbc.20152