Cowden syndrome (CS) is a rare genetic disorder with autosomal dominant inheritance, linked to germline mutations in the PTEN tumor suppressor gene on chromosome 10. Cowden syndrome often co-exists with Lhermitte–Duclos disease (LDD), with LDD included as a major criterion in CD diagnosis. This case involves a woman presenting with many of the classic diagnostic criterions and associations of CD, as well as with several comorbidities and unique objective findings.