A case of metastatic renal cell carcinoma to the ovary

Abstract

A 52-year-old woman had a pathological fracture of the right femur. On histopathological examination bone metastasis from renal cell carcinoma was suspected. Abdominal computed tomography showed a heterogeneous mass (9.1 x 7.8 x 6.5 cm) in the left kidney and a cystic multilocular mass (12 x 10 cm) in the pelvis. Bone scintigraphy revealed an abnormal uptake in the left coracoid process, right third rib, and right distal femur and proximal tibia. Clinical diagnosis was left renal cancer with multiple bone metastases (cT2NOM1, stage IV) and a right ovarian tumor. We performed left radical nephrectomy and resection of right ovarian tumor by bilateral adnexectomy. On histopathological examination, the left kidney tumor was diagnosed as renal cell carcinoma (clear cell carcinoma with chromophobe component, G2 > G1). The ovarian tumor consisted of carcinoma of clear cell type (G2) that resembled components of left renal cell carcinoma, confirming the diagnosis of metastatic renal clear cell carcinoma to the ovary. Although she underwent immunotherapy with interferon, she died 10 months after nephrectomy. Metastasis to the ovary from renal clear cell carcinoma is very rare and only 18 cases have been reported in the literature. This rarity may be related to the difficulty of differential diagnosis between metastatic renal cell carcinoma to the ovary and primary ovarian clear cell carcinoma. Elaborate analysis of microscopic features and immunohistochemical profiles may help in the distinction of this metastatic lesion.

患者は52歳、女性。右大腿骨の病的骨折をきたし、骨折片の病理学組織学的検索で腎細胞癌(淡明細胞癌、G2)を疑われた。CT検査で左腎腫瘍(9.1×7.8×6.5cm)および多房嚢胞性の右卵巣腫瘍(12×10cm)を認めた。腎癌cT2N0M1, stageIVと診断し、卵巣腫瘍は悪性腫瘍を強く疑ったが原発性か転移性かの鑑別は困難であった。経腹的根治的左腎摘除、右卵巣腫瘍摘出および両側付属器切除術を施行し、病理組織学的には腎は一部に嫌色素細胞癌を伴う淡明細胞癌(G2>G1)であった。卵巣は腎で認めたG2の淡明細胞癌と類似した組織型であり、大腿骨の転移巣と同じ組織型を呈していたことから、腎癌の卵巣転移と診断した。術後インターフェロンによる後療法を施行したが、10ヵ月後、肺転移の出現と骨転移巣の増大のため死亡した。腎細胞癌の卵巣転移はきわめて稀であり、文献上18例の報告しかない。(著者抄録)