The unusual nested carcinoma of the renal pelvis
A 54-year-old postmenopausal lady presented with pain in the right arm and right upper thigh of three months duration. There was no history of trauma. General physical examination revealed bilateral axillary and inguinal lymphadenopathy. There was mild tenderness on palpation over the right arm and thigh; however, no definite swelling was noted. Rest of the systemic examination was normal. Complete hemogram, liver and renal function tests, and urinalysis were within normal limits.\nThe patient gave history of attending a primary health center where a provisional diagnosis of bone tuberculosis was made considering its high incidence in a developing country like india, and the patient was started on antitubercular therapy (ATT). The patient was referred to a higher center with no signs of improvement on ATT. Radiological investigations demonstrated a mass in the right radius and right iliac bone, and a fine needle aspiration cytology performed from these sites showed features of a metastatic carcinoma.\nFor further evaluation and investigation of the primary site, a whole body PET-CT and 99mTc-MDP bone scan were done. 99mTc-MDP bone scan exhibited abnormal increased tracer concentration in multiple hot spots in calvarium, ribs, right ilium, and right radius; suggestive of skeletal metastases. Whole body PET-CT scan showed metabolically active large lytic destructive lesions in multiple bones and a subtle enhancing soft tissue in midpolar region of left kidney. The patient was referred to our center for further management. Based on the above investigations, a clinical diagnosis of skeletal metastases with a possible primary in the kidney was considered. Three consecutive urine samples were sent for cytology, which was negative for malignant cells.\nWith the possibility of renal primary, the patient was taken up for laparotomy. Peroperatively, both kidneys appeared unremarkable, except that the left renal pelvis and upper one third of left ureter were indurated with adhesions present between them and the surrounding tissue. Rest of the visualized intra-abdominal structures were within normal limits. Hence, a left nephro-ureterectomy was performed.\nGross specimen consisted of left kidney with left adrenal gland and perinephric fat altogether measuring 9 × 6 × 5 cms, enclosed within the gerota's fascia with attached ureter of 11 cm length. On cutting open, a grey-white tumor was identified in the wall of the renal pelvis, which was extending into one of the calyceal walls and into the upper 7 cm of the ureter []. No papillary growth was identified. Rest of the kidney and adjacent adrenal gland appeared uninvolved. Regional lymph nodes were not included in the specimen.\nMicroscopically, a tumor was seen arising from the urothelium with massive infiltration of the lamina propria []. The tumor cells were arranged in the form of irregularly distributed variable-sized organized nests, few of which showed cribriform and microcystic pattern. The cells were medium-sized with mild to moderate anisocytosis, moderate amount of pale eosinophilic cytoplasm, rounded nuclei, granular chromatin with inconspicuous nucleoli in most of the cells. No significant nuclear polymorphism was noted in the majority of the tumor; however, few large tumor cells displaying some atypia were seen in the deeper areas. Mitoticfigure were rare with one mitoticfigure identified per 10 high power fields. Small irregular nests of tumor cells were seen invading in between the deep muscle bundles and also perineurally. Nests of tumor cells were seen invading into the pericalyceal areas of lower half of left kidney. Sections from pelvis and ureter showed tumor cells infiltrating through the wall of the pelvis and the ureter into the peripelvic fat. Renal vessels, resected margin of the ureter, and left adrenal gland were, however, free of tumor.\nThe differential diagnosis included the NVUC and neuroendocrine tumor, for which immunohistochemistry was performed. The tumor cells were diffusely immunoreactive for Pan CK, CK 7, CK 20 [] and were negative for neuroendocrine markers NSE and Chromogranin []. Based on these findings, final diagnosis of nested variant of urothelial carcinoma was made.\nIn view of the widespread metastases, postoperatively, the patient was put on systemic chemotherapy including cisplatin and gemcitabine. Till date, she has received three cycles of chemotherapy, but her clinical condition has not improved in these three months.