病歷報告：罕見無症狀轉移腎臟鱗狀上皮癌腫瘤
鄭偉權、張殷綸

高雄長庚紀念醫院泌尿科

Squamous Cell Carcinoma of Renal Parenchymal: Silent Presentation with A Rare Malignancy Metastasis

Wei Quen Tee, Yin-Lun Chang

Department of Urology, Chang Gung Memorial Hospital, Kaohsiung Medical Center, Chang Gung University College of Medicine, Kaohsiung, Taiwan.

Case Report

We present a rare case report of renal parenchymal squamous cell carcinoma (SCC) metastasis from esophageal. This 50-year-old man had an underlying disease of middle-thoracic esophageal squamous cell carcinoma, moderately differentiated with mediastinal lymph nodes and left supraclavicular lymph nodes metastasis, cT4bN3M1, stage IVB. He received radiotherapy and chemotherapy with a PF cycle. After regimen treatment, CT showed partial response and the PET scan showed a metabolic complete response. However, the right kidney was accidentally found with an ill-defined poor enhanced hypodense mass lesion about 4cm. He denied flank soreness, dysuria, and hematuria. A renal mass biopsy showed squamous cell carcinoma.

Therefore, this patient received right hand assistant retroperitoneoscopic nephroureterectomy. The final pathologic showed metastatic squamous cell carcinoma and the margin showed negative. Further regular follow-up was suggested.

Discussion

In Taiwan, esophageal cancer is in 2020 the 9^th leading cause of death. The most common sites of metastasis are the liver, lung, bone, and adrenal glands. Metastases of esophageal carcinoma in the kidney are considered to be extremely rare, especially unilateral renal metastasis. Autopsy studies have shown that about 12% of patients dying of cancer have renal metastases, making the kidney a common metastatic site. However, the clinical detection of these tumors is rare. Diagnosis is often difficult due to vague presenting symptoms, despite extensive renal involvement. Hematuria and proteinuria occur in fewer than 20% of patients. Therefore, it is often found accidentally such as in our case.

There are differences in clinical manifestation between primary renal cell carcinoma (RCC) and metastatic carcinoma. Most RCCs are on average larger than metastatic renal tumors. Metastatic renal tumors are frequently observed in subcapsular locations. The typical pattern of renal metastases consists of multiple small nodules and almost all cases are associated with widespread non-renal metastases. Moreover, unilateral, solitary renal metastasis is extremely rare. Despite the rarity of renal metastasis, the differential diagnosis of kidney SCC should be investigated when a renal mass is accompanied by longstanding renal calculi. Factors that enhance the likelihood of SCC are chronic irritation, inflammation, and infection that promote squamous metaplasia. Chronic pyelonephritis or nephrolithiasis is frequently present in the pertinent medical history of SCC.

In our case, since the tumor seemed to be a solitary renal mass metastasis, a nephrectomy was performed. The pathological assessment showed a single metastatic SCC with a margin clear. The present case serves to demonstrate that careful follow-up is needed for esophageal cancer patients with cancer in another organ including rare site metastasis.