Indian Journal of Pathology and Microbiology

CASE REPORT
Year
: 2010  |  Volume : 53  |  Issue : 3  |  Page : 541--543

Papillary renal cell carcinoma with lipocyte-like cells: A rare morphological variant or an indication of aggressiveness?


Aysegul Sari1, Gozde Evcim1, Murat Ermete1, Kaan Bal2, Ahmet Bolukbasi2,  
1 Department of Pathology, Izmir Ataturk Training and Research Hospital, Izmir, Turkey
2 Department of Urology, Izmir Ataturk Training and Research Hospital, Izmir, Turkey

Correspondence Address:
Aysegul Sari
Ataturk Caddesi, Firat Apt. No:184, Kat:3 Daire:6 Alsancak-Izmir
Turkey

Abstract

Papillary renal cell carcinoma (PRCC) is the second most common carcinoma of the kidney, which is classified into two types. Type 1 displays single layer of cells with scanty pale cytoplasm and type 2 has pseudostratified high-grade nuclei with eosinophilic cytoplasm. Recently, apart from these two types, oncocytic PRCC and clear-cell PRCC have been described. To the best of our knowledge, lipocyte-like cells have not yet been reported to accompany any subtypes of renal cell carcinoma. Herein, we report a case of PRCC with lipocyte-like cells and sarcomatoid features. Lipocyte-like cells might represent a special type of PRCC or this feature may be an indication of poor prognosis regarding its association with sarcomatoid change.



How to cite this article:
Sari A, Evcim G, Ermete M, Bal K, Bolukbasi A. Papillary renal cell carcinoma with lipocyte-like cells: A rare morphological variant or an indication of aggressiveness?.Indian J Pathol Microbiol 2010;53:541-543


How to cite this URL:
Sari A, Evcim G, Ermete M, Bal K, Bolukbasi A. Papillary renal cell carcinoma with lipocyte-like cells: A rare morphological variant or an indication of aggressiveness?. Indian J Pathol Microbiol [serial online] 2010 [cited 2021 Nov 27 ];53:541-543
Available from: https://www.ijpmonline.org/text.asp?2010/53/3/541/68291


Full Text

 Introduction



Papillary renal cell carcinoma (PRCC) can be morphologically classified into two variants designated as Type 1 and Type 2. [1],[2] Sarcomatoid changes can occur in all histologic subtypes of RCC and is associated with poor prognosis. [3] Recently, oncocytic PRCC, [4],[5] clear cell PRCC and RCC with papillary architecture and clear cell components have been described. [6],[7] Lipocyte-Like Cells (LCL) have not been reported to accompany any subtype of RCC. Herein we present an unusual case of a PRCC with LCL and sarcomatoid features, as we believe that documenting cases with different morphological features might reveal new variants of PRCC.

 Case Report



A 44-year-old man presented with macroscopic hematuria of one-year duration. Ultrasonography (USG) revealed a solid tumoral mass on the right kidney. Abdominal computer tomography (CT) demonstrated a 17 x 12 cm of heterogeneous tumoral mass on the right kidney. Right radical nephrectomy was performed. Macroscopically, 16 x 13 cm, unencapsulated tumoral mass was seen with a central white-yellowish area containing foci of orange spots and necrotic areas. Peripherally, the tumor had a different appearance with gray-white, lobulated and solid features. Low-power microscopic examination of the tumor showed a compact tubular growth pattern [Figure 1]. Densely packed, irregular tubular structures were lined by two types of cells. The first one was the single layers of cells with hyperchromatic nuclei and eosinophilic cytoplasm. The second type of cell population was composed of large and clear cytoplasms with hyperchromatic and eccentrically located nuclei, reminiscent of lipocytes or signet-cells [Figure 2]. Tumoral cells occasionally formed small papillary projections without obvious fibrovascular cores. Intraluminal epithelial protrusions or scattered, dissociated eosinophilic cells were observed in the tubular lumina [Figure 2]b. Neoplastic LCL made up approximately 60% of total neoplastic area of the epithelial part of the tumor. Aggregates of foamy macrophages, necrosis and cholesterol clefts were also present. Apart from the epithelial component, sarcomatoid areas composed of atypical spindle cells without any heterologous elements were also observed. Transition between epithelial and sarcomatoid components was inconspicuous.

Lipocyte-like cells were negative with Alcian Blue (AB) and Mucicarmine stains. In the epithelial component, alpha-methylacyl-CoA racemase (AMACR) showed diffuse and strong positive staining in both types of cells. Cytokeratin 7 (CK7) was positive in a lesser number in both cell types [Figure 3]. CD10 was only focally positive, and S-100 was negative in both types of cells. Sarcomatoid component showed only focal positivity with pancytokeratin.

The tumor was confined to the kidney without any involvement of perirenal fat tissue. No systemic disease was detected on metastatic work-up. The patient received postoperative radiotherapy for six weeks. Six months after the operation he developed massive hematemesis. Upper gastric endoscopic biopsy revealed an ulcerated mucosa and hyperplastic polyp. The patient subsequently died because of recurrent massive upper gastrointestinal bleeding.

 Discussion



Papillary renal cell carcinoma is morphologically subdivided into two subtypes for diagnostic purposes. Type 1 is more common, displays single layer of cells with scanty pale cytoplasm and has a more favorable prognosis. Type 2 has pseudostratified high-grade nuclei with eosinophilic cytoplasm. [1],[2] Papillary renal cell carcinoma is composed of varying proportions of papillae and tubules. Compact tubules or short papillae resembling glomeruli form the solid variant of PRCC. Papillary excrescences within the tubules may also be seen. [2] Papillary renal cell carcinoma virtually always show positive immunostaining for AMACR and CK7, but less frequently express CD10. [2],[6] In contrast, conventional RCC lack immunoreactivity with AMACR and CK7, but typically express CD10. [6]

Sarcomatoid change in PRCC does not represent a special type but indicates poor prognosis. [3] To date several variants of PRCC have been documented. Recently, oncocytic PRCC, [4],[5] clear cell PRCC and RCC with papillary architecture and clear cell components have been described. [6],[7] Papillary renal cell carcinoma with clear cell changes has been reported and these cases were investigated based on cytogenetic studies. [8],[9] Some of the cases reported as 'clear cell PRCC' and 'RCC with papillary architecture and clear-cell components' [6],[7] were associated with end-stage kidney disease. Histopathologic features of these two tumors were similar; both had papillary architecture either densely packed, cystic or in tubulo-alveolar arrangement. Variable percentage of the neoplastic cells had clear cytoplasm reminiscent of conventional clear cell carcinoma cells. Nuclei of these clear cells were located centrally or basally. The major differences between these two entities were in cytogenetical findings and the AMACR negativity in 'clear cell PRCC'. The cytogenetic findings and AMACR and CK7 positivity in 'RCC with papillary architecture and clear cell components' revealed that they belong to subgroup of PRCC rather than conventional renal cell carcinoma. [7] Differently from the clear cell components of all these cases, the clear cells in our case look like lipocytes rather than the clear cells of conventional RCC. In our case, nuclei of the clear cells were flat and hyperchromatic and pushed to one side of the cytoplasm. Apart from the large clear LCL, other characteristic features of our case were the extensive tightly packed tubular pattern and the diffuse and strong expression of AMACR in both clear cells and eosinophilic cells. The latter feature encouraged us to think this tumor as a variant of PRCC.

Lipocyte-like cells in our case did not represent the heterologous element of the sarcomatoid component because these cells were present in only epithelial part of the tumor, and stained positively with CK7 and AMACR, but did not with S100.

Urothelial carcinomas (UC) very rarely have LCL and are called under the term lipid/lipoid-cell variant. Most of the cases reported with this variant were high-grade carcinomas and died due to tumor progression and metastatic disease. [10]

In conclusion, LCLs might constitute a special type of PRCC or this feature may be an indication of progression in RCCs. Further cases with similar features might reveal a new variant of PRCC. Until then a thorough examination with extensive sampling of the tumor should be done when LCL is encountered in PRCC in order not to miss any sarcomatoid change. Close follow-up might also be necessary for these patients to detect early metastasis and tumor progression.

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