Carcinoid Tumor of the Kidney with Morphologic and Immunohistochemical Profile of a Hindgut Endocrine Tumor: Report of a Case

Abstract

A 54-year-old man underwent a radical nephrectomy for a presumed renal cell carcinoma. The tumor was large, showed areas of cystic degeneration and calcification, and had completely obliterated the normal renal parenchyma. The light microscopic appearance was atypical for renal cell carcinoma, and when electron microscopy revealed innumerable neurosecretory granules a diagnosis of carcinoid tumor was made. The tumor cells were argentaffin- and argyrophil-negative but were chromogranin-, neuron-specific enolase-, and leu-7-positive. When tested with a battery of antibodies against specific polypeptide hormones, the tumor exhibited diffuse pancreatic polypeptide and focal somatostatin immunoreactivity. Our case represents only the 16th case of carcinoid tumor of the kidney to be reported and the first with demonstrated pancreatic polypeptide immunoreactivity. The predominantly trabecular histology, nonreactivity with silver stains, and immunohistochemical profile of this case are common characteristics of hindgut carcinoids, suggesting that, like rectal carcinoids, renal carcinoids are tumors of hindgut endocrine cells.

Primary carcinoid tumor arising within mature teratoma of the kidney: report of a rare entity and review of the literature

“…Cytologically, the nuclei were uniformly round with "salt-and-pepper" chromatin pattern. Although these histological features are typical of carcinoid tumors and may assist with diagnosis, they give the lesion a pseudopapillary appearance, which may lead to misdiagnosis [20]. In a recent review of renal carcinoid tumors, the histopathological diagnosis was initially mistaken in 14.5% of reported cases [7], probably because of limited awareness about this pathological condition and the absence of carcinoid syndrome clinically.…”

Morphological classification of renal cancer

“…The nuclei of the small cell variants are hyperchromatic and oval with abundant mitoses, whereas the nuclei of the more differentiated tumors are round-shaped with less anaplasia. Alternating broad trabeculae and anastomosing cords embedded in a well-vascularized stroma are the main characteristics of the growth pattern [7].…”

Primary Carcinoid Tumour of the Kidney: A Review of the Literature

“…The cells have a swollen mitochondria with poorly developed rough endoplasmic reticulum and prominent Golgi complexes [34, 40, 41, 53, 55, 69, 72, 74]. …”