上泌尿道腫瘤罕見的鑑別診斷- 分化不良漿細胞瘤案例報告與文獻回顧

黃英哲¹ 、羅浩綸¹

¹高雄長庚紀念醫院外科部泌尿科

Rare differential diagnosis of upper tract urothelial tumor: A case report and review of the anaplastic plasmacytoma

Ying-Che Huang¹、Hao-Lun Luo¹

¹Divisions of Urology, Department of Surgery, Kaohsiung Chang Gung Memorial Hospital

Case description: A 80-year-old male presented to our outpatient department with a chief complaint of impaired renal function for months. The patient’s medical history is significant for 1) Chronic kidney disease stage 4, 2) type 2 diabetes mellitus. Physical examination did not find a palpable kidney, lower extremity edema, or right costovertebral angle tenderness. The computed tomography (CT) favored the left upper ureteral tumor with hydronephrosis and suspicion of lymph node (LN) metastasis. A complete blood count revealed a normal white blood cell count of 6.8 × 103/µl, with a hemoglobin of 11.6 g/dL and platelets 140 × 103/ul. Blood chemistry showed sodium to be 136 mEq/l; potassium, 4.2 mEq/l; serum creatinine, 2.29 mg/dl. Urine examination found pyuria and bacteria, but no hematuria. Under the clinical diagnosis of a left upper ureteral tumor with LN metastasis, the patient was taken for surgery. Intraoperatively, cystoscopy did not find any bladder tumor. However, the left upper ureteral mass with psoas adhesion and obvious peri-hilar LN were noted. Left robotic-assisted nephroureterectomy with lymphadenectomy was performed. On gross examination, there was one solid, soft and whitish tumor over the lower third of the renal pelvis extending to the middle ureter measuring 12.0 x 3.0 x 2.0 cm, and peri-hilar LN measuring up to 3.0 x 1.5 x 0.4 cm. Histology report indicated diffuse infiltration of incohesive round tumor cells separated by delicate fibrous septa in sections of the ureter and renal pelvis. The neoplastic cells bear vesicular chromatin, pleomorphic and enlarged nuclei. Lymph nodes showed intact nodal architecture without malignancy. Immunohistochemical studies showed reactivity with antibodies to CD138, as expected in plasma cells. The postoperative course was uneventful and was discharged in the following days. Currently, the patient receives follow-ups in our Oncology outpatient department for further evaluation and radiation therapy in our hospital.

Discussion: Extramedullary plasmacytoma is rare and only a few cases are recorded in the previous studies^1-3. The diagnosis criteria of extramedullary plasmacytoma include (1) No M-protein in serum and/or urine (2) Extramedullary tumor of clonal plasma cells (3) Normal bone marrow (4) Normal skeletal survey (5) No related organ or tissue impairment⁴. Preoperative image studies (CT scan, excretory urography and arteriography) are not specific and the lesion may mimic renal cell carcinoma (RCC) or urothelial carcinoma (UC). Treatment of extramedullary renal plasmacytoma includes radical nephroureterectomy or/and radiation therapy. Most of the extramedullary renal plasmacytomas have good oncological outcome⁵, however, some rare malignant cases are also reported and require further adjuvant chemotherapy⁶. 

Conclusions: Extramedullary plasmacytoma is a rare neoplasm and may mimic RCC or UC. The diagnosis depends on the histopathology and immunohistochemistry of the tumor. Although most cases behave benignly, malignant transformation does occur in a few cases. Further outpatient follow-up is needed for those patients.