Acute renal hypoperfusion and reversible renal atrophy caused by renal hilar paraganglioma in a child: a case report

Abstract

Background

Paraganglioma (PGL) are rare neuroendocrine tumors arising from extra-adrenal paraganglia. Renal hilar PGLs are exceptionally uncommon in children, and acute renal hypoperfusion with apparent renal atrophy due to extrinsic vascular compression has rarely been reported.

Case presentation

We report a child presenting with episodic hypertension, headache, dizziness, vomiting, and diaphoresis. Serial imaging demonstrated a small renal hilar mass associated with rapidly progressive renal hypoperfusion and acute reduction in left renal size. Renal angiography revealed focal compression of the left renal artery. Biochemical evaluation showed elevated catecholamines with activation of the renin–angiotensin–aldosterone system. Laparoscopic kidney-preserving tumor resection was performed, and histopathology confirmed a sympathetic PGL. Postoperatively, blood pressure normalized, and 6-month follow-up CT demonstrated restoration of left renal perfusion with marked recovery of renal size after complete tumor resection.

Conclusions

Acute renal hypoperfusion and apparent renal atrophy caused by extrinsic vascular compression may be reversible. Early recognition of renovascular compromise and timely kidney-preserving surgical intervention may prevent irreversible nephron loss in children. Genetic counseling, germline mutation screening, and long-term surveillance should also be considered in postoperative management.

Background

Paraganglioma (PGL) are rare neuroendocrine tumors originating from extra-adrenal paraganglia and are part of the pheochromocytoma-PGL spectrum [1, 2]. Pediatric PGL are uncommon and are frequently functional, typically presenting with hypertension and adrenergic symptoms [3, 4]. Renal hilar involvement is exceedingly rare, particularly in children.

Most reported renal hilar PGL are diagnosed because of catecholamine excess rather than local renal effects [5]. Direct mechanical compression of the renal vasculature resulting in acute renal hypoperfusion or rapid renal size reduction has rarely been emphasized [6]. Here, we describe a pediatric renal hilar PGL presenting with acute and reversible renal hypoperfusion and apparent renal atrophy caused by extrinsic vascular compression, highlighting an important and potentially underrecognized nephrological phenomenon.

Case presentation

A 5-year-9-month-old boy presented with newly detected hypertension for 5 days and paroxysmal dizziness accompanied by vomiting and diaphoresis for 1 day. He had been previously healthy, with no family history of hypertension. Five days before admission, blood pressure was 145/95 mmHg. Abdominal CT performed at a local hospital revealed a relatively small left kidney with mildly reduced perfusion compared with the right kidney (Fig. 1A). Two days before admission, repeat imaging demonstrated markedly decreased left renal perfusion with further reduction in renal size (Fig. 1B). Brain MRI showed no diffusion restriction or perfusion abnormality (Fig. 1C).

Fig. 1.

Preoperative imaging and functional evaluation showing a renal hilar mass with rapid progression of left renal hypoperfusion/atrophy. (A) The findings of the abdominal CT scan at the local hospital 5 days before admission. (B) Repeat contrast-enhanced abdominal CT 2 days before admission showing markedly decreased perfusion and further reduction in the size of the left kidney. (C) Brain MRI showing no diffusion restriction or perfusion abnormality. (D) Contrast-enhanced abdominal CT after admission demonstrating a solid mass in the left renal hilar region adjacent to the abdominal aorta, with a clear boundary from the renal parenchyma. (E) Renal angiography revealing focal compression of the left renal artery with poor visualization of the distal branches, suggesting ischemic change/atrophy of the left kidney. (F) Radionuclide renography showing reduced left renal volume with preserved secretory/excretory function; split renal function: left GFR 19.8 mL/min and right GFR 58.6 mL/min

After referral to our center, blood pressure was controlled with oral terazosin and sustained-release nifedipine. Abdominal ultrasonography and contrast-enhanced CT identified a well-defined solid mass in the left renal hilar region, clearly separated from the renal parenchyma (Fig. 1D). Renal angiography demonstrated focal compression of the left renal artery with poor distal visualization (Fig. 1E). Radionuclide renography showed reduced left renal volume with preserved but diminished function (left GFR 19.8 mL/min; right GFR 58.6 mL/min) (Fig. 1F).

Laboratory evaluation revealed normal complete blood count, liver function, and electrolyte levels. Renal function was within the normal range, with normal serum creatinine. Biochemical testing demonstrated markedly elevated catecholamine-related indices, including norepinephrine (NE) 15,258.0 pmol/L, normetanephrine 13.42 nmol/L, and metanephrine 0.15 nmol/L. Components of the renin-angiotensin-aldosterone system were also increased, with plasma renin activity (PRA) 4.20 ng/mL/hr, angiotensin II 190.16 pg/mL, and aldosterone 284.29 pg/mL. Twenty-four-hour urine analysis showed a urine volume of 2.8 L/24 h, vanillylmandelic acid (VMA) 4.48 mg/24 h, metanephrine (MN) 7.0 µg/24 h, and normetanephrine (NMN) 89 µg/24 h, slightly above our institutional upper reference limit (57.1 µg/24 h). Given the marked polyuria, these 24-hour urinary results were interpreted as supportive biochemical evidence and were considered together with plasma catecholamine levels and imaging findings.

Laparoscopic resection of the left renal hilar mass was performed with preservation of the renal artery, vein, and renal pelvis (Fig. 2A-F). Histopathological examination demonstrated a well-circumscribed tumor with classic zellballen architecture and negative margins (Fig. 3A-L), consistent with a sympathetic PGL arising in the renal hilum.

Fig. 2.

Intraoperative findings and key steps of laparoscopic renal hilar tumor resection with kidney preservation. (A) Exposure of the left kidney via opening the peritoneum along the left paracolic gutter. (B) A firm mass (approximately 2.0 × 1.5 × 1.5 cm) located inferior to the left renal vein, with multiple feeding vessels on the surface. (C-D) Venous drainage of tumor vessels into the left renal vein (C) and inferior vena cava (D). (E) Careful dissection and ligation of tumor-feeding/draining vessels. (F) Complete tumor excision with preservation of the left renal artery, vein, renal pelvis, and perihilar renal capsule. (Red arrows indicate the superior and inferior vascular structures associated with the tumor)

Fig. 3.

Gross, histological, and immunohistochemical characteristics of the resected tumor. (A) Gross examination showing a solid yellowish-red cut surface with a moderate texture and a well-defined capsule; adjacent blood vessels are visible. (B) Tumor cells arranged in nests, trabeculae, or organoid (zellballen-like) patterns around blood vessels, surrounded by a thin fibrous capsule (H&E staining, ×200). (C) Sparse tumor stroma with abundant vascular networks within the lesion (H&E staining, ×200). (D) Tumor cells with abundant eosinophilic cytoplasm and oval nuclei of variable size; nucleoli are occasionally visible (H&E staining, ×400). (E) Tumor cells displaying a nested and sheet-like growth pattern (H&E staining, ×100). (F) Tumor cells arranged in coarse trabecular structures, with occasional pathological mitotic figures observed (H&E staining, ×400). (G) Immunohistochemical staining showing diffuse positivity for chromogranin A (CgA) (×100). (H) Tumor cells negative for HMB45 (×100). (I) Ki-67 labeling index of approximately 3%, indicating low proliferative activity (×100). (J) Tumor cells negative for Melan-A (×100). (K) Diffuse cytoplasmic positivity for synaptophysin (Syn) (×100). (L) The sustentacular cells show positive expression of S-100 protein, supporting the diagnosis of PGLs (×100)

At the 6-month follow-up, contrast-enhanced CT demonstrated marked restoration of left renal perfusion after complete tumor resection, with substantial recovery of left renal size, approaching that of the contralateral kidney (Fig. 4A, B). No residual or recurrent mass was identified. Postoperative laboratory evaluation at the 3-month follow-up demonstrated normalization of catecholamine levels and renin-angiotensin-aldosterone system parameters.

Fig. 4.

Preoperative and 6-month postoperative CT comparison demonstrating recovery of left renal perfusion and renal size after kidney-preserving tumor resection. (A) Preoperative contrast-enhanced CT showing markedly decreased perfusion of the left kidney with reduction in renal size compared with the contralateral side. (B) Contrast-enhanced CT obtained 6 months after surgery showing complete tumor removal, marked restoration of left renal perfusion, and substantial recovery of left renal size, with the bilateral kidneys becoming nearly symmetric

Blood pressure remained within the normal range without antihypertensive medications during follow-up. Longer-term monitoring of split renal function and blood pressure is ongoing. We plan to reassess renal function longitudinally, including split renal function where clinically indicated.

Patient perspective

From the parents’ perspective, the sudden onset of hypertension accompanied by dizziness, vomiting, and sweating in a previously healthy child was concerning. Imaging findings indicating a rapid decrease in the size of the left kidney within a short period raised additional concerns about potential permanent renal damage.

The medical team explained that the mass located near the renal hilum could significantly affect renal blood flow and blood pressure regulation, which helped the family understand the need for timely intervention. After discussion of treatment options, the parents agreed to proceed with laparoscopic tumor resection with the goal of preserving renal function.

The perioperative course was uneventful. Postoperatively, the child’s blood pressure normalized, and follow-up imaging demonstrated improvement in renal perfusion and renal size. From the parents’ perspective, early diagnosis and kidney-preserving surgery were important for symptom resolution and protection of long-term renal function.

Discussion

Renal hilar PGLs in children are exceedingly uncommon, and most reported cases present with catecholamine-related symptoms rather than local renal effects [7, 8]. The present case is distinguished by rapid progression from mild renal hypoperfusion to marked perfusion impairment with an acute reduction in renal size documented over only a few days. This pattern strongly suggests a clinically significant mechanical effect of the tumor on the renal vasculature.

Accurate pathological diagnosis is essential when evaluating pediatric renal hilar masses. The absence of blastemal or epithelial differentiation excluded Wilms tumor and pediatric renal cell carcinoma [9]. Perivascular epithelioid cell tumor was considered because of the perihilar location and vascularity but was ruled out by negative melanocytic markers. In contrast, the classic zellballen architecture, sustentacular S-100–positive cells, diffuse neuroendocrine marker expression, and low Ki-67 index supported the diagnosis of PGL [10].

Hypertension in this patient likely reflected a dual mechanism [11]. Catecholamine hypersecretion accounted for the adrenergic symptoms, whereas activation of the renin–angiotensin–aldosterone system suggested renovascular involvement, a recognized secondary mechanism of hypertension in PGLs [12, 13]. Anatomically, the renal hilum is a vulnerable site where even a small tumor may compromise renal arterial inflow. Angiographic evidence of renal artery compression correlated closely with the biochemical abnormalities and imaging-documented hypoperfusion in this case [14].

The most clinically significant aspect of this case is the acute and reversible nature of the renal changes. Acute renal atrophy is typically associated with intrinsic renal disease or primary vascular occlusive processes rather than external compression [15–17]. Postoperative recovery of renal perfusion and near normalization of renal size indicate that the ischemic changes were predominantly functional. This observation highlights a narrow therapeutic window during which prompt surgical decompression may prevent irreversible nephron loss.

This case report has several notable strengths. First, it provides rare, well-documented evidence of acute and reversible renal hypoperfusion with apparent renal atrophy caused by extrinsic vascular compression from a small renal hilar PGL in a child. The rapid temporal evolution of renal perfusion impairment, captured by serial imaging over a short interval, offers a unique perspective on dynamic renovascular compromise rather than chronic parenchymal loss.

Second, the integration of multimodal assessments—including cross-sectional imaging, renal angiography, radionuclide renography, biochemical evaluation, and postoperative follow-up—allowed for coherent clinicopathological correlation and strengthened the causal link between vascular compression, hypertension, and renal dysfunction [18]. Importantly, demonstration of postoperative recovery in renal perfusion and size highlights the potential reversibility of ischemic renal changes when timely, kidney-preserving intervention is undertaken.

Several limitations should also be acknowledged. As a single case report, the findings cannot be generalized to all pediatric renal hilar PGL or to other causes of renal hypoperfusion. The absence of pre-illness baseline renal imaging precludes precise quantification of the degree of acute versus preexisting renal size asymmetry. Although short-term postoperative outcomes were favorable, longer-term follow-up is required to determine the durability of renal functional recovery and to monitor for potential tumor recurrence or late-onset hypertension.

Although vascular ultrasonography and renal angiography provided indirect evidence of renovascular compromise, direct quantitative hemodynamic measurements of renal blood flow were not available. Given the high prevalence of germline alterations in pediatric PGL, genetic counseling and SDHx germline testing are important components of postoperative management. In the present case, testing was recommended but was not performed due to parental preference and financial considerations. A further limitation is the lack of long-term functional follow-up data, including repeat split GFR assessment. Continued surveillance is ongoing to evaluate the durability of renal functional recovery and long-term blood pressure control.

Despite these limitations, this case provides important clinical insight into a potentially reversible form of acute renal hypoperfusion in children and underscores the value of early recognition and nephron-sparing management in selected renovascular presentations.

Conclusions

Pediatric renal hilar PGL may present with acute and reversible renal hypoperfusion and apparent renal atrophy due to mechanical vascular compression. Early recognition of renovascular compromise and timely kidney-preserving surgical intervention are essential to preserve renal function. Genetic counseling, germline mutation screening (e.g., SDHx testing), and long-term surveillance for recurrence as well as blood pressure and renal function are recommended in postoperative management.

Author contributions

All authors contributed to patient management and manuscript preparation. All authors read and approved the final manuscript.

Funding

This study was supported by Science and Technology project of Kunming Municipal Commission of Health and Construction (No. 2024-SW(L)-07, 2025-04-05-015, 2025-SW(T)-01), Kunming Medical Joint Project of Yunnan Science and Technology Department (No. 202001AY070001-271, 202301AY070001-108), Research Project of Yunnan Provincial Clinical Medical Center (No. 2024YNLCYXZX0430, 2024YNLCYXZX0428), Medical reserve talents of Yunnan Province Medical reserve talents of Yunnan Province (No. H-2025004), Scientific research project of Yunnan Clinical Medical Center and Open Research Fund of Clinical Research Center for Children’s Health and Diseases of Yunnan Province. The funding bodies had no role in the study design, data collection, data analysis, data interpretation, or manuscript writing.

Data availability

The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.

Declarations

Ethics approval and consent to participate

This study was approved by the ethical committee of Kunming Children’s Hospital (2025-05-129-K01); This study was conducted in accordance with relevant guidelines and regulations. The data in this study were obtained from this patient and his legal guardian. Written informed consent was obtained from the patient’s parents. Informed consent was obtained from the patient’s parents and/or legal guardians for the publication of identifying information/images in online open access publications.

Consent for publication

Written informed consent has been obtained from the patient’s parents, allowing for the publication of clinical details and/or clinical images.

Competing interests

The authors declare no competing interests.