Crizotinib-Associated Renal Cysts: A Case Series

Abstract

Crizotinib is an anaplastic lymphoma kinase (ALK) inhibitor, used as a targeted chemotherapeutic agent in ALK-positive cases of nonsmall cell lung carcinoma. Although uncommon, it may be associated with the formation of new renal cysts, which may be simple or complex, or the enlargement of preexisting simple renal cysts or their transformation into complex cysts. These cysts usually regress partially or completely but may rarely enlarge over time or get complicated by infection or abscess formation. Such cases may even require dose reduction or withholding crizotinib. Although documented in clinical literature, this entity is not well known among radiologists. Knowledge of this entity helps in preventing erroneous diagnosis of the new kidney “lesion” as metastasis or disease progression and avoids an unnecessary biopsy. We describe a series of four cases which developed complex renal cysts during treatment with crizotinib to demonstrate this point.

Development of crizotinib-associated renal cyst in a non-small cell lung cancer patient with ALK fusion: a case report and review of the literature

“…CARCs could be simple or complex cysts. A simple cyst can be asymptomatic, but complex CARCs can be complicated with infection, rupture, or abscess formation [ 36 – 38 ]. By abdominal CT scan, simple cysts are near water density with an upper threshold of 20 Hounsfield units (HU) [ 39 ], while complexing cysts could be hyperdense contents, septations, mixed solid cystic appearance, and poorly defined margins [ 38 ].…”

“…A simple cyst can be asymptomatic, but complex CARCs can be complicated with infection, rupture, or abscess formation [ 36 – 38 ]. By abdominal CT scan, simple cysts are near water density with an upper threshold of 20 Hounsfield units (HU) [ 39 ], while complexing cysts could be hyperdense contents, septations, mixed solid cystic appearance, and poorly defined margins [ 38 ]. Complex CARCs fall into categories III and IV of Bosniak classification [ 40 ], which usually need surgical resection by standard guideline due to higher malignant potentiality.…”