Introduction: Poland syndrome is a congenital disorder related to chest and hand anomalies on one side of the body. Its etiology remains unclear, with an ipsilateral vascular alteration (of unknown origin) to the subclavian artery in early embryogenesis being the currently accepted theory. Cavernous malformations are vascular hamartomas, which have been linked to a genetic etiology, particularly in familial cases, which commonly present with multiple lesions. Our case report is the first to describe multiple cavernous malformations associated with Poland syndrome, further supporting the vascular etiology theory, but pointing to a genetic rather than a mechanistic factor disrupting blood flow in the corresponding vessels.

Case presentation: A 41-year-old Caucasian man with Poland syndrome on the right side of his body presented to our hospital with a secondary generalized seizure and was found to have multiple cavernous malformations distributed in his brain, cerebellum, and brain stem, with a predominance of lesions in the left hemisphere.

Conclusion: The distribution of cavernous malformations in the left hemisphere and the right-sided Poland syndrome in our patient could not be explained by a mechanistic disruption of one of the subclavian arteries. A genetic alteration, as in familial cavernous malformations, would be a more appropriate etiologic diagnosis of Poland syndrome in our patient. Further genetic and pathological studies of the involved blood vessels in patients with Poland syndrome could lead to a better understanding of the disease.