Clear Cell Renal Cell Carcinoma With Extensive Osseous Metaplasia: Report of a Rare Case

Clinicopathologic analysis of renal cell carcinoma containing Intratumoral fat with and without osseous metaplasia

“…Previously, intratumoral adipose with or without osseous metaplasia has been documented in a few clear cell, papillary I/II, and chromophobe RCC cases [1][2][3][4][5][6][7][8][9][10][11][12][13][14]. We demonstrated that the frequency of adipose metaplasia was similar between different subtypes of RCC.…”

“…Radiographic evidence of fat within a renal mass can be seen in both AML and RCC, potentially complicating the radiographic diagnosis of AML versus RCC. Intratumoral adipose in RCC is usually associated with osseous metaplasia [1][2][3][4][5][6][7][8][9][10][11][12][13][14], but AML is also known to rarely present with calcifications [15][16][17][18][19][20]. Furthermore, RCC has been reported to contain adipose without evidence of calcification on CT and/or pathologic analysis [3,[7][8][9]14].…”

“…In RCC in which intratumoral adipose is present, the adipose is often associated with osseous metaplasia, defined as bone matrix with associated osteoblasts, osteoclasts, adipocytes, and/or hematopoietic cells [1][2][3][4][5][6][7][8][9][10][11][12][13][14]. The exact etiology of intratumoral adipose is unknown, but there are three recognized mechanisms by which Table 2) (10X magnification).…”

Renal cell carcinoma with osseous metaplasia: A case report and literature review

“…Osseous metaplasia has also been reported in patients with renal diseases, including less than 20 cases of the major subtypes of RCC [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][23][24][25][26]. Table 1 summarizes clinicopathologic features of these cases, including the present case, reported in case studies of osseous metaplasia associated with RCC.…”

“…Sarcomatoid differentiation is also seen in a subset of RCCs and is generally associated with poor patient outcomes. By contrast, metaplastic bone formation with or without bone marrow elements in RCC is extremely rare yet has been reported predominantly in clear cell [2][3][4][5][6][7][8][9][10][11][12] and chromophobe [13][14][15][16] subtypes. We here present a case of papillary RCC with osseous metaplasia along with a review of the literature on this unusual condition.…”