Primary renal small cell carcinoma: A case report

Abstract

Background: Small cell carcinoma (SCC) is a malignant tumour that is frequently accompanied by extensive metastasis. Primary renal SCC has typical characteristics related to SCC and is extremely rare, with no uniform treatment standard. Clinical treatment is mainly based on the literature. Here we report the diagnosis and treatment of an interesting case of primary renal SCC.

Case summary: We report a tortuous course of treatment for a 68-year-old man. Four years before diagnosis, the patient developed continuous gross haematuria, during which he underwent several ureteral biopsies, ureteral stricture relief, and urine exfoliated cell examinations; however, SCC was not confirmed. One month before radical resection of the renal pelvic carcinoma, the severe haematuria recurred. Computed tomography revealed transitional cell carcinoma in the right kidney and right upper ureter. A preoperative examination exluded the possibility of a pulmonary origin of the tumour, and primary renal SCC was diagnosed. The postoperative pathology findings were suggestive of SCC. The patient was treated with combined chemotherapy but died of tumour progression at 7 mo postoperative.

Conclusion: Our patient's disease onset in the context of a succession of regular testing and the fact that it occurred so quickly with perirenal encroachment immediately after diagnosis reveals the cruel and unforgiving side of the disease. Furthermore, patients with poor comprehensive treatment results require new treatment regimens.

Keywords: Case report; Clinical features; Diagnosis; Kidney; Small cell carcinoma; Treatment.

Figure 1

Postoperative pathology in 2016 and 2019. A: After ureteral biopsy in 2016. Carcinoma tissue was suspected. Under the microscope, mucosal tissue was mixed with hemorrhagic necrotic tissue, and the surface of the mucosa was covered with urothelium, which showed papillary or solid nest like inverted growth. The tumor nucleus was oval, the cytoplasm was deep, mitosis was occasionally seen, and the focal area seemed to be a staggered arrangement of solid nestlike cells and proliferative stroma; B: After ureteral bladder replantation. Chronic mucositis and mild atypical hyperplasia was considered. Under the microscope, the urinary tract epithelium covered by the mucosal surface of some areas proliferated, and grew to the lamina propria to form a small nest or glandular tube-like structure, focal squamous metaplasia, partial mucosal surface necrosis, covered with a large amount of red staining without structure, and significant interstitial edema in the lamina propria; C: after ureteral biopsy in 2019. Polypoid change was showed. Under the microscope, part of the surface is lined with hyperplastic urothelial epithelium and lamina propria fibrous interstitial hyperplasia.

Figure 2

There are the results of computed tomography examination before and after operation. There was no obvious occupation of liver, lung and mediastinum before operation, but these sites began to occupy space since December, especially the change was quite rapid between March and April, and tumor metastasis occurred at the operation site. A: Kidney; B: Liver; C: Lung; D: Mediastinum.

Figure 3

Postoperative pathology in 2020. High-grade invasive papillary urothelial carcinoma and small cell carcinoma were suspected. A: Under the microscope, tumor cells were composed of two components: one type of cells was nest-like arrangement, with larger cell volume, abundant cytoplasm, large nuclei, deep staining and obvious atypia; the other type of cells was uniformly distributed in sheets, with medium to small cells, abundant cytoplasm or medium cytoplasm, and round nuclei. And the boundary between the two forms is clear (A1 and A2); B: There was no obvious abnormality at the broken end of the ureter (B1 and B2).