Acquired cystic disease (ACD)-associated renal cell carcinoma (RCC) is the most common tumour in patients with acquired cystic kidney disease (ACKD) in end-stage renal disease (ESRD)

Incidentally diagnosed on radiologic follow-up in patients with chronic renal disease, or at the time of nephrectomy/transplantation.

Solitary or multifocal, and sometimes bilateral, well circumscribed tumor(s), also in association with atypical cysts (Fig.1A), adenomas, or other additional renal neoplasms (ie, papillary RCC).

The tumors have a yellow to tan cut surface and a variable growth patterns; however, papillary, solid, cystic and sieve-like features predominant. . Clear cell cytology is multifocally present, and occasionally small vacuoles are present within the cytoplasm giving a microcystic appearance (Fig.1B) . Oxalate crystal deposits (Fig.1C) are frequently seen in areas of neoplasia as well as in the non-neoplastic tissue. ² In contrast to papillary RCC, most ACD-associated RCCs are CK7 negative.

Fig 1: Acquired cystic disease-associated RCC occurs in the setting of acquired cystic and chronic end stage kidney disease. The tumor presents as a mass in an atrophic kidney often with multiple cortical cysts (A, gross image). The tumor has heterogeneous morphologic findings including solid, papillary, cystic and sieve-like growth patterns and eosinophilic to focally clear cell cytology (B). Although not required for the diagnosis, oxalate crystals are often seen within the tumor (C).

Indolent clinical behavior, but occasionally can metastasize if a high-grade tumor with sarcomatous or rhabdoid features

Although genetic data are limited, microarray and FISH analyses have revealed relatively frequent numerical abnormalities of chromosomes 3 and 16 along with gains of chromosomes 7 and 17.^2,4,5 

Recurrent KMT2C or TSC2 gene mutations have been reported.⁶ but not VHL mutations.⁷