Intracardiac myxoma of unusual topography and rare clinical presentation in the context of congenital polymalformative syndrome: a case report.

Background: Cardiac myxoma is the most common benign cardiac tumour. It is a benign tumour with functionally malignant behaviour and has the potential for systemic embolization. Some forms of myxoma are familial; others are isolated. However, the presence of right atrial myxoma has not yet been described in association with ectrodactyly and ectodermal dysplasia syndrome. Case summary: A 28-year-old patient ectrodactyly and ectodermal dysplasia disorder presented to the Emergency Room with abdominal pain and anasarca for 3 weeks. A transthoracic cardiac ultrasound revealed a lobulated mass with a sessile infiltrative base between the atrial side of the tricuspid valve and the free wall of the inferior vena cava, with partial obstruction. Cardiac magnetic resonance imaging identified a non-thrombotic, polylobulated, budding mass extending from the tricuspid valve and prolapsing through the junction with the inferior vena cava. The cardiac myxoma was confirmed by an intravascular biopsy performed under transoesophageal echocardiography guidance. The patient underwent surgery with clinical improvement. Discussion: Rare congenital syndromes of ectrodactyly and ectodermal dysplasia have been described in the literature with various atypical plurisystemic malformations. However, cardiac involvement has rarely been described and the presence of right atrial myxoma has never been reported. This clinical case demonstrates the possible association between rare congenital syndromes of ectrodactyly and ectodermal dysplasia with the development of intracardiac myxoma. The potential tumorigenic role of variants in tumour suppressor genes, involved in urinary tract and limb development, may explain the onset of cardiac myxoma in the context of ectrodactyly and ectodermal dysplasia syndrome.