Hemihyperplasia

Clinical History

A 34-year-old female presents with a history of recurrent abdominal pain and multiple episodes of transient small bowel obstruction, for which a CT is performed. Her previous medical history included unilateral nephrectomy during childhood and myomectomy 5 years ago.

Imaging Findings

Abdominal and Chest X-Ray: Hemihyperplasia of the right side, particularly evident in the breasts and pelvis. Dilated small bowel loops with air-fluid levels are seen in the abdomen.

CT: Dilated small bowel loops with abrupt change in caliber, consistent with small bowel obstruction, probably due to adhesions. Also, signs of nephrectomy and a clear asymmetry between right and left sides of the abdomen, especially evident in subcutaneous tissue.

Discussion

Background

Hemihyperplasia is defined as an asymmetric growth due to overgrowth of one or more body parts. This term should be preferred to hemihypertrophy [1]. It can be isolated or associated with syndromes, such as Beckwith-Wiedemann syndrome (BWS), Proteus syndrome, neurofibromatosis type 1, mosaic trisomy 8, and Klippel-Trenaunay syndrome [2].

Clinical Perspective

Overgrowth syndromes have overlapping clinical manifestations and do not have well-established genetic tests, so imaging is an important contributor to diagnosis [3].
BWS is a paediatric overgrowth disorder involving a predisposition for embryonal malignancies, most commonly Wilms tumour and hepatoblastoma. Other tumours include rhabdomyosarcoma, adrenocortical carcinoma, and neuroblastoma. BWS clinical presentation is highly variable; major findings include, but are not limited to, macroglossia, omphalocoele, macrosomia and hemihyperplasia [4]. There is clinical overlap between isolated hemihyperplasia (IH) and BWS, both of which are associated with Wilms tumours. Nevertheless, the majority of BWS patients have a molecular abnormality involving the imprinted cluster of genes at 11p15.5, while most of IH patients have no identified etiology. The diagnosis of IH should be made by a clinical geneticist, because overgrowth syndromes must be excluded [2].

Imaging Perspective

Hemihyperplasia was an incidental imaging finding in an adult referred for abdominal pain; no other valuable information was provided regarding her physical examination. Since nephrectomy and obvious body asymmetry were detected on imaging, a careful evaluation of the clinical history was performed. She had been followed since 18 months-old in another hospital, due to Wilms tumour. No information in her adult clinical history mentioned genetic syndromes. Wilms tumour and hemihyperplasia can appear both in IH and BWS.

Outcome

Most of the tumours associated with BWS occur in the first 8–10 years of life, with very few reported beyond this age [4]. In isolated hemihyperplasia, tumoirs are detected in patients with and without molecular abnormalities; therefore, all IH patients should be screened. Guidelines for IH screening include abdominal ultrasound every 3 months until 7 years and serum alpha-fetoprotein every 3 months until 4 years [2]. Tumour surveillance may not have impact on survival, but has the potential to reduce morbidity [1]. To our knowledge, there are no proposed screenings for adults. Our patient was successfully treated conservatively and later referred to outpatient surgical care.

Take Home Message, Teaching Points

Hemihyperplasia can be an isolated finding or associated with clinical syndromes. It is commonly linked with increased risk for malignancy, especially Wilms tumours and hepatoblastoma, for which screening is recommended in childhood.

Differential Diagnosis List

Final Diagnosis

Hemihyperplasia

URL:	https://www.eurorad.org/case/14284
DOI:	10.1594/EURORAD/CASE.14284
ISSN:	1563-4086