Introduction: The Bardet-Biedl syndrome is a rare autosomal recessive disorder, which associates obesity, pigmentary retinopathy, hexadactyly, hypogenitalism, renal dysfunction and mental retardation. Other abnormalities can be observed in the Bardet-Biedl syndrome, but few cutaneous abnormalities have been described.
Case report: A 41 year-old woman, suffering from a Bardet-Biedl syndrome diagnosed when she was 7 Years old, presented with an atypical pseudo verruca-like, dark red lesion of the interbuttock area that had developed over fifteen Years and had become a handicap. The histological examination revealed a double component: epithelial, papillomatous and acanthosic on the one hand and vascular and lymphatic on the other, suggesting a lymphangioma with epidermal hyperplasia. Magnetic resonance imaging of the sacral area revealed a median subcutaneous lesion, extending deeply to the third coccygial vertebra.
Discussion: Such a lymphangioma is unusual. Because it occurred during a rare polymalformative syndrome, we suggest that it may represent a new clinical sign that can be observed during the Bardet-Biedl syndrome.