腎黏液性管狀细胞癌和梭形细胞癌－罕見病例報告與文獻回顧

吳冠賢^1,2, 李經家^1,2,3*

¹高雄醫學大學附設中和醫院 泌尿部、²高雄醫學大學 臨床醫學研究所、^３高雄醫學大學醫學系 泌尿學科

Renal mucinous tubular and spindle cell carcinoma: A case report and review of literature

Kuan-Hsien Wu^1,2, Ching-Chia Li^1,2,3*

¹ Department of Urology, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan

² Graduate Institute of Clinical Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan

³ Department of Urology, School of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan

Introduction: Mucinous tubular and spindle cell carcinoma (MTSCC) represents a rare subtype of low-grade renal cell carcinoma (RCC). It was incorporated as a distinct entity in the latest 2004 WHO classification of kidney tumors, although it is susceptible to misdiagnosis as other highly malignant tumors. This tumor typically carries a relatively favorable prognosis compared to other malignant renal tumors. Through this clinical case, we explore a comprehensive understanding of MTSCC through different aspects.

Case report: A 73-year-old woman has underlying disease of hypertension, dyslipidemia, chronic viral hepatitis C. Left renal mass was incidentally found during health examination. She denied having fever, other urinary or gastrointestinal symptoms, and any contact history. A contrast computed tomography (CT) scan of the abdomen depicted a well-circumscribed 4.2 cm heterogeneous enhanced mass at the left kidney. There was neither regional metastatic lymphadenopathy nor distant metastasis. We arranged left laparoscopic radical nephrectomy. The patient recovered well after the surgery. Microscopically, a well-circumscribed renal tumor composed of tightly packed, elongated, and anastomosing tubules lined by low-grade cuboidal cells merging with bland spindle cells. Focal stromal mucin shows prominent vacuolization. Immunohistochemical analysis revealed that the tumor cells were diffusely positive for PAX8, CK7, and alphamethylacyl-CoA racemase (AMACR). Repeated CT after 6 months follow up disclosed no definite evidence of local recurrence or distant metastasis. The patient was alive with no evidence of disease.

Conclusion: MTSCC of the kidney is a rare renal epithelial neoplasm. Patients are often diagnosed accidentally due to the indolent clinical behavior. The diagnosis of MTSCC primarily relies on pathological examinations, including cytogenetic and immunohistochemical studies, which display a unique histological profile. Surgical resection is vital to long-term survival. Through this clinical case and literature review, we aim to enhance understanding of the diagnosis and treatment of this tumor.