Renal Oncocytoma With Both Lymphovascular Invasion and Prominent Intracytoplasmic Vacuole-Like Spaces: A Case Report and Review of the Literature

Here we report a case of renal oncocytoma in a 68 year-old male. The diagnosis was initially made on a needle biopsy 6 years prior to the partial nephrectomy. The case is unique that in addition to the gross and microscopic features commonly seen in renal oncocytomas, both lymphovascular invasion and prominent intracytoplasmic vacuole-like spaces are also present in this tumor. Although vascular invasion is increasingly recognized as compatible with renal oncocytoma, intracytoplasmic vacuoles are a rare and unusual finding that may lead to diagnostic difficulty. The diagnosis of renal oncocytoma was confirmed after immunohistochemistry was performed to argue against succinate dehydrogenase deficient renal cell carcinoma (RCC) and chromophobe RCC. This case highlights the importance for practicing pathologists to recognize the rare co-occurrence of lymphovascular invasion and large intracytoplasmic vacuole-like spaces in renal oncocytoma. Other differential diagnoses may include emerging renal tumor entities, such as the recently-proposed eosinophilic vacuolated tumor.

Active surveillance for bilateral renal oncocytomas already resected on one side: a case report

Introduction: To report our experience of active surveillance of new bilateral masses after left laparoscopic partial nephrectomy for oncocytoma. Method: A 67-year old man underwent left laparoscopic partial nephrectomy for a renal mass and histology confirmed oncocytoma. At follow-up magnetic resonance imaging (MRI) showed new renal bilateral masses: hence, sonogram-guided percutaneous core renal biopsies were performed confirming the presence of oncocytoma in both kidneys. A re-biopsy was required because of an increasing of the left mass while a histological was also consistent with oncocytoma. Result: At follow of 8 years the patient is well and shows a normal renal function. Conclusion: Oncocytomas show minimal growth rate or progression. MRI has an important role in the appropriate follow-up of renal oncocytomas. Patients with biopsy proven oncocytoma may be managed conservatively by active surveillance (AS).

Tissue-Based Immunohistochemical Markers for Diagnosis and Classification of Renal Cell Carcinoma

The development and description of renal cell carcinoma (RCC) subtypes has led to an increase in demand for tissue biomarkers. This has implications not only in informing diagnosis, but also in guiding treatment selection and in prognostication. Although historically, many immunohistochemical (IHC) stains have been widely characterized for RCC subtypes, challenges may arise in interpreting these results. These may include variations in tumor classification, specimen collection and processing, and IHC techniques. In light of the reclassification of RCC subtypes in 2016, there remains a requirement for a comprehensive outline of tissue biomarkers that may be used to differentiate between RCC subtypes and distinguish these from other non-renal neoplasms. In this review, concise summaries of the commonest RCC subtypes, including clear cell, papillary, and chromophobe RCC, have been provided. Important differences have been highlighted between chromophobe RCC and renal oncocytomas. An overview of the current landscape of tissue biomarkers in other RCC subtypes has also been explored, revealing the variable staining results reported for some markers, whilst highlighting the essential markers for diagnosis in other subtypes.

Renal Oncocytoma: Report of Two Cases and Review of the Literature

Introduction: Renal oncocytomas are benign tumours arising from the intercalated cells of the collecting ducts and account for 3% to 7% of primary renal tumours. It was first described by Zippel in 1942. Oncocytomas are mostly asymptomatic and often discovered incidentally. They are often diagnosed postoperatively due to clinical and radiographic challenges in differentiating them from renal cell carcinoma. Presentation of Case: The present study reports two cases of renal oncocytoma in a 61‑year‑old man who was asymptomatic and a 73‑year‑old woman who was symptomatic. Relevant clinical and imaging data on the two patients were reviewed. Both patients underwent nephrectomy via flank incisions. Discussion: The typical morphologic features of oncocytoma were observed on histological examination of the excised kidney speci­mens. The postoperative course of each patient was uneventful and they were discharged 14 and 6-days post‑surgery, respec­tively. In addition, the present study reviews the literature regarding the clinical, radiological and pathological characteristics of renal oncocytoma. Conclusion: Renal oncocytoma though is benign and has an excellent prognosis, the preoperative diagnostic challenges invariable warranted radical nephrectomy.