Hemihyperplasia isolated

Note	Usually hemihypertrophy occurs sporadically but familial cases are reported. Though molecular defects have not been identified in all cases, there is evidence that IH occurs due to epigenetic defects or paternal uniparental disomy of genes of 11p15 in somatic mosaic form.
Phenotype and clinics	Cases with hemihypertrophy not fulfilling criteria of complicated hemihypertrophies are grouped under isolated hemihypertrophy or hemihyperplasia. Though the title included the word 'hemi', only one limb may be involved. The condition is usually nonprogressive and the body disproportion does not change. Bone age may or may not be increased on the hypertrophied side. Some cases of isolated hemihyperplasia have other features like naevi, capillary haemangiomas and hypertrichosis. Mental retardation may be present. There are no specific laboratory abnormalities. Viscera (kidney) on the hypertrophied side may be enlarged. Plexiform neurofibromas may look like hemihypertrophy.
	A child with isolated hemihypertrophy involving left lower limb. Note Poland anomaly and hypoplastic nipple on left side - a rare associated feature.
Neoplastic risk	The risk of neoplasm is around 5%. Wilms tumour is the commonest; but other tumors like hepatoblastoma, adrenal cell tumour and leiomyosarcoma are also reported. Three monthly ultrasonographic follow up for Wilms tumour up to 5 years and then yearly up to the completion of growth is recommended.
Treatment	Usually limb discrepancy is mild and no treatment is required. Corrective shoes, orthopedic procedures may be needed to correct limb length discrepancy. Evaluation of cognitive function and appropriate training may be needed.
Prognosis	The condition is nonprogressive and the prognosis is good. Close follow up for early detection of Wilms tumour is needed.

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