Spontaneous regression of renal cell carcinoma: Reality or myth?

Primary Retroperitoneal Carcinomas: New Insights into Pathogenesis and Clinical Management in Comparison with Ovarian Carcinomas and Carcinoma of Unknown Primary

Primary retroperitoneal carcinomas are very rare tumors. Their pathogenesis remains unknown but may be associated with that of ovarian carcinomas, considering the similarity in morphology and gender preference. Although metaplasia of coelomic epithelium is the most widely accepted theory, the pathogenesis of retroperitoneal carcinomas may differ by histologic subtype, like ovarian carcinomas. Mucinous carcinoma, which develops in both women and men, may originate in both primordial germ cells and Walthard cell nests that may be derived from the fallopian tube. Serous carcinomas may be associated with endosalpingiosis, the presence of fallopian tube-like epithelium outside the fallopian tube, and a remnant Müllerian tract. Endometrioid and clear cell carcinomas appear to be associated with extraovarian endometriosis. Additionally, both carcinomas in the retroperitoneal lymph nodes may be metastatic diseases from endometrial and/or renal cell cancer that regress spontaneously (carcinoma of unknown primary). Retroperitoneal carcinomas are difficult to diagnose, as they have no characteristic symptoms and signs. Surgery is the cornerstone of treatment, but the necessity of chemotherapy may depend on histological subtype. Further studies are necessary, in particular studies on endosalpingiosis, as endosalpingiosis is a poorly understood condition, although it is associated with the development of both serous and mucinous carcinomas.

Complete spontaneous regression of a primary renal cell carcinoma. Report of a pathological proven case and review of the literature

Regression of primary renal cell carcinoma (RCC) is a rare phenomenon and for several reasons many of the reported cases have been questioned. We present a case that can be considered a true spontaneous and complete regression of a primary RCC. A 79-year-old female underwent nephrectomy because a renal tumor. At the time of surgery image studies showed a small para-aortic lymph node. The tumor measured 3cm and was analyzed completely. Histology showed a fibro-inflammatory lesion with necrosis, foamy macrophages and inflammatory cells. No neoplastic cells were observed and the lesion was interpreted as a localized type of xanthogranulomatous pyelonephritis. One year later a CT control scan, showed that the para-aortic lymph node had increased in size to 4cm. Fine needle aspiration revealed features of clear RCC. Metastatic dissemination was limited so surgical removal of the para-aortic lymph node was performed and the cytologic diagnosis confirmed.

Beyond conventional immune-checkpoint inhibition - novel immunotherapies for renal cell carcinoma

The management of advanced-stage renal cell carcinoma (RCC) has been transformed by the development of immune-checkpoint inhibitors (ICIs). Nonetheless, most patients do not derive durable clinical benefit from these agents. Importantly, unlike other immunotherapy-responsive solid tumours, most RCCs have only a moderate mutational burden, and paradoxically, high levels of tumour CD8+ T cell infiltration are associated with a worse prognosis in patients with this disease. Building on the successes of antibodies targeting the PD-1 and CTLA4 immune checkpoints, multiple innovative immunotherapies are now in clinical development for the treatment of patients with RCC, including ICIs with novel targets, co-stimulatory pathway agonists, modified cytokines, metabolic pathway modulators, cell therapies and therapeutic vaccines. However, the successful development of such novel immune-based treatments and of immunotherapy-based combinations will require a disease-specific framework that incorporates a deep understanding of RCC immunobiology. In this Review, using the structure provided by the well-described cancer-immunity cycle, we outline the key steps required for a successful antitumour immune response in the context of RCC, and describe the development of promising new immunotherapies within the context of this framework. With this approach, we summarize and analyse the most encouraging targets of novel immune-based therapies within the RCC microenvironment, and review the landscape of emerging antigen-directed therapies for this disease.

Spontaneous Regression of Delayed Pulmonary and Mediastinal Metastases from Clear Cell Renal Cell Carcinoma

Renal cell carcinoma (RCC) is often metastatic at diagnosis. Conventional therapies such as chemotherapy, radiotherapy, and hormonal therapy have generally proven ineffective in the treatment of RCC. The abscopal effect, specifically, the ability of localized radiation to trigger systemic antitumor effects, has been reported to lead to regression of non-irradiated distant tumor lesions. Herein, we report 3 patients with non-metastatic clear cell RCC (CCRCC) who underwent a nephrectomy and experienced metachronous pulmonary/mediastinal metastases confirmed as CCRCC. No patients underwent radiation post-nephrectomy or pulmonary metastasectomy. The mean duration was 7.24 weeks from the last negative chest CT prior to the nephrectomy and 96.2 weeks post-nephrectomy. All patients achieved durable complete response by RECIST criteria, with a mean follow-up duration of 115 months. Our case series represents the largest in the literature of patients who underwent a nephrectomy for CCRCC with no pre-existing pulmonary/mediastinal metastatic disease confirmed by chest CT, did not undergo radiotherapy, and developed significantly delayed CCRCC pulmonary/mediastinal metastases. We highlight the spontaneous regression of delayed metastatic disease and the role of immune responses in curtailing the growth of pulmonary metastasis in CCRCC.

Metastatic clear cell renal cell carcinoma in isolated retroperitoneal lymph node without evidence of primary tumor in kidneys: A case report

BACKGROUND

Retroperitoneal lymph node dissection (RPLND) plays a diagnostic, therapeutic, and prognostic role in myriad urologic malignancies, including testicular carcinoma, renal cell carcinoma (RCC), and upper urinary tract urothelial carcinoma. RCC represents 2% of all cancers with approximately 25% of patients presenting with advanced disease. Clear cell RCC (CCRCC) is the most common RCC, accounting for 75%-80% of all RCC.

CASE SUMMARY

A 71-year-old man presented with a history of benign prostatic hypertrophy. He was asymptomatic without any hematuria, pain, or other urinary symptoms. A computed tomography (CT) scan of the abdomen and pelvis showed a 1.8 cm left retroperitoneal lymph node. There was no evidence of renal pathology. A core biopsy was performed of the left para-aortic lymph node. Although the primary tumor site was unknown, the morphological and immunohistochemical features were most consistent with CCRCC. A RPLND was performed which revealed a single mass 5.5 cm in greatest dimension with extensive necrosis. The retroperitoneal lymph node was most compatible with CCRCC. A nephrectomy was not conducted as a renal mass had not been detected on any prior imaging studies. The patient did not receive any type of adjuvant therapy. The patient underwent surveillance with serial CT scans with contrast of the chest, abdomen, and pelvis for the next 5 years, all of which demonstrated no recurrent or metastatic disease and no evidence of retroperitoneal adenopathy.

CONCLUSION

Our unique case emphasizes the therapeutic role of metastasectomy in metastatic CCRCC even in the absence of primary tumor in the kidneys.