Horseshoe adrenal gland in association with asplenia: presentation of six new cases and review of the literature.

Background: Asplenia syndrome is a form of heterotaxy characterized by bilateral right-sidedness. Congenital fusion of the adrenal glands ("horseshoe adrenal gland") is a less common feature of asplenia syndrome, most instances of which have been found at autopsy.

Purpose: To present clinical and imaging features of infants diagnosed with asplenia syndrome and horseshoe adrenal gland.

Materials And Methods: Six infants with asplenia syndrome were identified as having a horseshoe adrenal gland. Medical records and imaging studies were reviewed to determine clinical presentation, associated anomalies, and outcome. The literature was reviewed for prior reports of horseshoe adrenal gland.

Results: Horseshoe adrenal gland was identified in five infants by sonography and one by CT, the latter confirmed by autopsy. In all cases, the horseshoe adrenal gland was pre-aortic. Besides features of asplenia syndrome, one infant also had associated vertebral anomalies and bilateral renal agenesis. Including the current cases, of 65 reported cases of horseshoe adrenal gland 34 (52%) were associated with asplenia, 24 (37%) with neural tube defects, 19 (29%) with renal anomalies, and 2 (3%) with Cornelia de Lange syndrome. Horseshoe adrenal gland has not been reported with polysplenia syndrome.

Conclusions: Horseshoe adrenal gland is a less common manifestation of asplenia that may be demonstrated by imaging. Horseshoe adrenal gland may be a differentiating feature between asplenia and polysplenia.