**8. Conclusions**

Microscopically, ACD-associated RCC is defined as a tumor having eosinophilic or oncocytic cytoplasm and is frequently associated with intratumoral oxalate crystal deposition [10, 17, 79] (Fig. 5b). Some investigators suggest that many microcysts maybe formed by intracyto‐ palsmic vacuoles mainly due to degenerative change. These crystals are multicolored under polarized microscopic observation. Papillary, tubular, cribriform or solid growth pattern may also be seen. Nuclear grade is frequently classified as Fuhrman grade 3 [10, 17, 25]. Clear cell change, sarcomatoid change or rhabdoid features may be present in some cases [10, 80, 81]. Immunohistochemically, neoplastic cells of ACD-associated RCC are positive for α-methyl‐ acyl-coenzyme A racemase (AMACR), CD10, CD57, GST-α, vinculin and c-met, but negative

Clear cell papillary RCC is seen in ESRD patients without ACDK. The tumors appear well circumscribed and usually well encapsulated. The cut surface is tan-white to yellow with grossly apparent fibrotic areas and ranges from completely solid to predominantly cystic. Microscopically, clear cell papillary RCC have variable tubular/acinar, papillary, and cycti‐ carchitectures [10, 74, 75]. The tumor cells have clear cytoplasm. Nuclear grade is often classified into Fuhrman grade 1 or 2. In contrast to ACD-associated RCC, clear cell papillary

Genetic profiles are distinct from classic papillary RCC or clear cell RCC. Gain of chromosomes 1, 2, 3, 6, 7, 10, 16, 17 and Y are observed in ACD-associated RCC [81, 82, 84-86]. Deletion of

The developing process of ACDK and RCC in long dialysis patients is still unclear. Several researchers reported the role of cytokine activation. Phosphorylated c-jun, the activated c-jun, which is a critical component of the AP-1 transcription factors that consist of homo- or heterodimers of basic region-leucine zipper proteins, is positive on staining of atypical hyperplastic cells in ACDK [87]. The concentration such as IL-6, -8, and VEGF is significantly high in the cystic fluid of ACDK [88]. Possibility of the relationship of calcium oxalate crystal and tumorigenesis has also been reported [17, 79, 89]. Immunohistochemical expression of oxidative stress markers, such as iNOS, 8-OHdG, and COX-2, are more frequently observed in ESRD-associated RCC than in conventional RCCs [90], since patients on dialysis are affected by oxidative stress which is caused by an imbalance between the production of reactive oxygen

ACD-associated RCC patients appearto show relatively good prognosis because of a low incidence of advanced disease [26]. In ACD-associated RCC patients treated with RN,

for cytokeratin 7 (CK7) and high molecular weight cytokeratins [10, 25, 27, 81-83].

RCC is positive for CK7 but negative for AMACR and CD10 [74, 75].

species and the cells ability to neutralize the reactive intermediates [91, 92].

3p25, +7, -Y are absent in clear cell papillary RCC [74].

*5. 1. 2. Clear Cell Papillary RCC*

152 Updates in Hemodialysis

**6. Etiology of RCC in ESRD**

**7. Prognosis**

ESRD patients on dialysis are at high risk for development of RCC. Periodic screening for RCC is recommended for these patients. MRI without use of contrast material would be useful for screening RCC in ESRD patients. ACD-associated RCC and clear cell papillary RCC are the current standard histological spectrum of RCCs arising from the kidney with ESRD. For patients with ESRD-associated RCC in early stage, less invasive surgical treatment is preferable to avoid postoperative systemic complications. Prognosis of ESRD-associated RCC patients is generally favorable when treated in early stage.
