[894] Renal Cell Carcinoma with Syncytial-Type Tumor Multinucleated Giant Cells, a Rare Variant of Clear Cell Renal Cell Carcinoma

Muhammad T Idrees, Theodore W Kieffer, David J Grignon, Jennifer B Kum. Indiana University, Indianapolis, IN

Background: Renal cell carcinoma (RCC) with syncytial-type tumor multinucleated giant cells (SGC) is a recently reported rare variant with only 5 cases reported in the English literature. Clinicopathologic features need to be evaluated in additional cases as it appears from published data that it may be associated with an aggressive clinical course. We report morphologic, immunophenotypic, and ultrastructural features in 5 additional cases.
Design: Five cases of RCC with SGC are identified from our files. All H&E slides are reviewed and immunohistochemical (IHC) studies are performed on representative tumor sections using a standard methods. IHC studies using antibodies against CAM5.2, AE1/3, vimentin, S100 protein, HMB45, SMA, CD10, CD68, EMA, hCG, CK20, CK7, and TFE-3 are performed on 3 cases. Ultrastructural studies are performed on 4 cases.
Results: Clinicopathologic information is available for 5 cases (Table 1); average tumor size is 7.2 cm. Three of 5 patients are male and 4 of 5 tumors are right sided. Two of 5 cases have sarcomatoid areas and 2 have lymph node involvement. One case each showed direct invasion of either the adrenal gland or liver. The adrenal gland is not examined in 2 cases. Microscopically, each tumor displays areas of classic clear cell RCC (CCRCC) and areas of mixed clear cells and SGC. The nuclear grades of SGC correspond to the existing CCRCC. SGC also show prominent emperipolesis and eosinophilic-hyaline globules. Ultrastructurally, the hyaline globules correspond to degenerative debris likely secondary to phagocytic activity. The staining profile of the SGC component is similar to the associated CCRCC and are PAS, vimentin, CD10, EMA, and AE1/3 positive; negative for S100, SMA, HMB45, CD68, TFE-3, hCG, CK20, CK7, mucicarmine, and PAS with diastase treatment.

Table 1. Renal Cell Carcinoma with Syncytial-Type Multinucleated Giant Cells

Case	1	2	3	4	5
Laterality	R	R	R	L	R
Sex	M	M	M	F	F
Age	43	62	57	60	60
Associated Tumor	CCRCC	CCRCC	CCRCC	CCRCC	CCRCC
Size	9.9	5.2	11.2	6	3.5
Stage	T4	T1b	T4	T3a	T1a
Fuhrman Grade	4	3	4	4	3
Sarcomatois Areas	Y	N	Y	N	N
Lymph Node Involvement	Y	Y	N	N	N
Direct Extension	Adrenal Gland	N	Liver	N	N

Conclusions: SGC in CCRCC is a rare but distinctive finding. The syncytial cells have the same immunoprofile as adjacent CCRCC. Additionally, they often show prominent emperipolesis and eosinophilic cytoplasmic globules. These tumors appear to present at higher stage and most likely represent an aggressive variant of RCC. Further studies are needed to document the prognostic differences.
Category: Genitourinary (including renal tumors)

Wednesday, March 21, 2012 9:30 AM

Poster Session V # 90, Wednesday Morning