Autosomal dominant polycystic kidney disease (ADPKD) is the most common heritable multifocal cystic disease encountered in clinical practice, and it is usually diagnosed in patients with family history by the evidence of markedly enlarged kidneys with multiple bilateral cysts at ultrasound (U.S.), computed tomography (CT) scan, or magnetic resonance imaging (MRI). In most cases, genetic testing is not required. Though ADPKD diagnosis is often straightforward, misdiagnosis is possible. Here we present a case of ADPKD misdiagnosis, followed by a review of the most important kidney heritable multifocal cystic diseases. Our case report demonstrates that ADPKD can be erroneously diagnosed when other kidney heritable multifocal cystic diseases occur without their distinguishing manifestations and when there is no genetic characterization among the relatives. A proper diagnosis of heritable diseases is crucial, as it allows an appropriate management of family members who carry disease allele, apart from patient management. Therefore, we suggest a careful differential diagnosis with possible molecular genetic analysis in presentations with familial cystic kidneys and suspicious clinical and radiological features.