Primary Renal Carcinoid Tumor: Report of Two Cases

Abstract

Introduction: Primary renal carcinoid tumors are a rare subset of neuroendocrine tumors arising in the kidneys. Although carcinoid syndrome has occasionally been described, most patients are asymptomatic at presentation.

Case presentations: We present 2 cases of primary renal carcinoid tumor and describe the workup, immunohistochemical analysis, treatment, and surveillance of each female patient. The first patient was found to have a renal mass on imaging during a workup of chronic abdominal pain and subsequently underwent a robotic radical nephrectomy. The second patient was found to have an incidental renal mass on imaging and subsequently underwent renal biopsy, followed by robot-assisted laparoscopic partial nephrectomy. In both cases, a gallium dotatate Ga 68-enhanced positron emission tomography/computed tomography scan was used to further assess disease burden.

Discussion: This report describes 2 cases of primary renal carcinoid tumor with unique presentations and management in our regional health care system. Because primary renal carcinoid tumors are quite uncommon, there are no clear established guidelines on preoperative imaging or posttreatment surveillance in patients with these tumors. There remains a large amount of variability in the diagnosis, workup, immunohistochemical analysis, treatment, and surveillance of patients with primary renal carcinoid tumors. As we learn more about this disease, we hope to optimize patient outcomes and standardize pretreatment workup and posttreatment surveillance.

Figure 1

Case 1. Series of axial contrast-enhanced computed tomography images of the abdomen, demonstrating an 8-cm, right renal mass as well as regional lymphadenopathy.

Figure 2

Case 2. Series of axial noncontrast and contrast-enhanced computed tomography images of the abdomen, demonstrating a 4.4-cm, enhancing right interpolar renal mass without any regional lymphadenopathy.

Figure 3

Case 2. Slides of histologic analyses with immunohistochemical staining of the partial nephrectomy specimen (×20). A: Hematoxylin-eosin stain. B: Synaptophysin stain. C: Chromogranin stain. D: Ki-67 stain.