American Board of Pathology (ABPath) 2025 – 400 Free Practice Questions to Pass the Exam

Multicystic dysplastic kidney (MCDK) is primarily characterized by the presence of multiple cysts and the absence of normal renal structures in a kidney, resulting from abnormal kidney development. This condition is most commonly unilateral, meaning that it typically affects only one kidney.

In a unilateral presentation, the affected kidney may show a non-functioning or poorly functioning structure due to the cystic changes, while the contralateral kidney usually develops normally. This is a key distinguishing feature because when MCDK is unilateral, the other kidney often compensates for the loss of function by hypertrophying or increasing in size.

Moreover, while some conditions affecting the kidneys can be hereditary, MCDK is not consistently associated with a hereditary pattern. Instead, it often arises sporadically due to environmental factors or disruptions in development during gestation.

The notion that MCDK represents a malignant process is also incorrect, as it is a developmental anomaly rather than a form of cancer.

In summary, the characterization of multicystic dysplastic kidney as usually unilateral is consistent with clinical observations and pathology, emphasizing its distinction from bilateral renal dysplasia or malignancy.