Secondary malignancies diagnosed using kidney needle core biopsies: a clinical and pathological study of 75 cases

Secondary Tumors of the Kidney: A Comprehensive Clinicopathologic Analysis

Metastases to the kidney are rare and were historically described in autopsy series, and the incidence ranged between 2.36% and 12.6%. However, in the contemporary literature with the improvements in imaging modalities (computed tomography scan and magnetic resonance imaging) and other health care screening services, metastatic tumors to the kidney are being diagnosed more frequently in surgical specimens. The utility of needle core biopsies in the primary evaluation of renal masses has also increased the number of sampled metastases, and as a result, only limited histologic material is available for evaluation in some cases and may potentially lead to diagnostic pitfalls. In the last decade, a few large clinical series have been published. In these series, the majority of metastatic tumors to the kidney are carcinomas, with the lung being the most common primary site. A significant number of the various tumor types with metastasis to the kidney are also associated with widespread metastases to other organs, and the renal metastasis may present several years after diagnosis of the primary tumor. The majority of secondary tumors of the kidney are asymptomatic, incidentally discovered, and solitary. There should be a high index of suspicion of metastasis to the kidney in patients with an associated enlarging renal lesion with minimal to no enhancement on imaging and tumor progression of a known high-grade nonrenal malignancy. Secondary tumors of the kidney can be accurately diagnosed by correlating histopathologic features with clinical and radiographic findings and the judicious use of ancillary studies.

Lung adenocarcinoma diagnosed incidentally after renal biopsy for suspected right renal cancer

We present a case of lung adenocarcinoma metastasizing to the right clear cell renal cell carcinoma diagnosed by computed tomography (CT)-guided renal biopsy and immunohistochemistry. A 72-year-old male patient had right lower abdominal pain for 3 days, followed by right loin pain for 10 days. On CT scan, renal cell cancer was suspected with multiple metastases. Renal cell cancer with metastatic lung adenocarcinoma was diagnosed on CT-guided renal biopsy with positive immunohistochemical markers. The patient, unfortunately, expired after few days of diagnosis. Tumor-to-tumor metastasis is an unusual disease, and its tumors are aggressive. A definite diagnosis of tumor-to-tumor metastasis is a clinical challenge. Immunohistochemistry helped us in the diagnosis without the primary lesion biopsy.

Urologic Diseases Germane to the Medical Renal Biopsy: Review of a Large Diagnostic Experience in the Context of the Renal Architecture and Its Environs

The kidney is one of the most complicated organs in development and is susceptible to more types of diseases than other organs. The disease spectrum includes developmental and cystic diseases, involvement by systemic diseases, iatrogenic complications, ascending infections and urinary tract obstruction, and neoplastic diseases. The diagnosis of kidney disease is unique involving 2 subspecialties, urologic pathology and renal pathology. Both renal and urologic pathologists employ the renal biopsy as a diagnostic modality. However, urologic pathologists commonly have a generous specimen in the form of a nephrectomy or partial nephrectomy while a renal pathologist requires ancillary modalities of immunofluorescence and electron microscopy. The 2 subspecialties differ in the disease spectrum they diagnose. This separation is not absolute as diseases of one subspecialty not infrequently appear in the diagnostic materials of the other. The presence of medical renal diseases in a nephrectomy specimen is well described and recommendations for reporting these findings have been formalized. However, urologic diseases appearing in a medical renal biopsy have received less attention. This review attempts to fill that gap by first reviewing the perirenal anatomy to illustrate why inadvertent biopsy of adjacent organs occurs and determine its incidence in renal biopsies followed by a discussion of gross anatomic features relevant to the microscopic domain of the medical renal biopsy. Unsuspected neoplasms and renal cysts and cystic kidney diseases will then be discussed as they create a diagnostic challenge for the renal pathologist who often has limited training and experience in these diseases.

Left renal mass presenting uncommon pattern of extension in a patient with intestinal malrotation

A 41-year-old man who had intestinal malrotation was presented with left renal tumor. The tumor extended venous thrombus up to hepatic portion and showed invasion in vessels and lymph nodes of mesocolon, which extended to porta hepatis. Needle biopsy of the renal tumor showed glandular adenocarcinoma. While colon cancer metastasis was possible, adenocarcinoma or glandular differentiation of urothelial carcinoma of the renal pelvis was also likely. The disease progressed rapidly and the patient died in a few months after the initial hospital visit. The very uncommon pattern of disease progression in this case was considered to be associated with intestinal malrotation, which is characterized by unfixed short mesenterium, abnormal alignment of mid- and hind-guts, and the lack of normal anatomical structures between peritoneum and retroperitoneum including the ligament of Treiz. This case provides an important implication of intestinal malrotation in disease progression, which may affect clinical decision-making in the extent of surgical resection including lymph node dissection.