A rare case of giant paraganglioma in the first porta hepatis area associated with neurofibromatosis type 1

A 22-year-old male patient was admitted to the surgical outpatient clinic due to a two-month history of progressive upper abdominal pain, palpitations, sweating, and headaches. His baseline blood pressure was approximately 178/120 mmHg, with a heart rate ranging from 115 to 130 beats per minute. Physical examination revealed significant emaciation. The abdomen was soft and non-tender, with no palpable abdominal masses. However, multiple cutaneous café-au-lait spots and subcutaneous nodules were observed (Figure 1A).

Figure 1.

Photograph of the patient’s abdomen and imaging examination before surgery. (A) Photograph of the patient’s abdomen of multiple cutaneous café-au-lait spots and subcutaneous nodules (arrows). (B) Coronal plane abdominal magnetic resonance on T2-weighted imaging (arrow). (C) MRI of thoracic paravertebral tumor (arrow). (D) Abdominal contrast-enhanced CT showed that the tumor had a rich blood supply (arrow). (E) MRI of intracranial abnormal signals (arrow). CT, computed tomography; MRI, magnetic resonance imaging.

Laboratory investigations demonstrated a white blood cell count of 9.24×10⁹/L (normal range, 3.5–9.5 ×10⁹/L), hemoglobin of 147 g/L (normal range, 130–175 g/L), and platelet count of 335 ×10⁹/L (normal range, 125–350 ×10⁹/L). Serum calcium was elevated at 2.77 mmol/L (normal range, 2.11–2.52 mmol/L), while 25-hydroxyvitamin D was low at 17.2 ng/mL (normal range, ≥20.00 ng/mL). Parathyroid hormone (PTH) was markedly elevated at 209.00 pg/mL (normal range, 15.00–65.00 pg/mL). Thyroid function tests were within normal limits. Plasma catecholamine levels (norepinephrine, dopamine, metanephrine, normetanephrine, and 3-methoxytyramine) exceeded the upper limit of detection. The urinary vanillylmandelic acid (VMA) level was elevated at 274.6 µmol/24 h (normal range, 20.00–90.00 µmol/24 h). Magnetic resonance imaging (MRI) revealed a large, well-circumscribed, oval mass in the first porta hepatis area, measuring 9.6 cm × 6.0 cm × 6.2 cm in size (Figure 1B). The mass demonstrated iso- to hyper-intense signal on plain T1-weighted imaging, heterogeneous slightly hyperintense to hypointense signal on T2-weighted imaging, hyperintense to slightly hypointense signal on diffusion-weighted imaging (DWI), and it exhibited marked enhancement post-contrast administration. The mass abutted the main portal vein, right renal vasculature, inferior vena cava, and pancreatic head. A paravertebral mass at the T8/9 level measured approximately 3.0 cm × 2.6 cm × 1.7 cm, showing isointensity on plain T1-weighted imaging and intense homogeneous enhancement post-contrast (Figure 1C). Contrast-enhanced abdominal computed tomography (CT) (Figure 1D) revealed a tumor with abundant blood supply. Multiple intracranial lesions demonstrated low signal intensity on T1-weighted imaging, high signal intensity on T2-weighted and fluid-attenuated inversion recovery (FLAIR) sequences (with areas of heterogeneous slightly hyperintense to hypointense signal), and isointensity on DWI (Figure 1E).

Based on the clinical presentation, these findings suggested that the porta hepatis tumor was distinct from the paravertebral and intracranial lesions, potentially representing a paraganglioma (PGL) associated with neurofibromatosis type 1 (NF1). A comprehensive evaluation and multidisciplinary team (MDT) discussion ruled out thyroid, adrenal, and pituitary disorders, supporting the initial diagnosis. Unfortunately, genetic testing and positron emission tomography (PET)/CT scans, such as ¹⁸F-fluorodeoxyglucose or ⁶⁸Ga-DOTATATE, were not performed preoperatively due to financial constraints. Additionally, these tests could delay urgent management in symptomatic patients. Surgical resection is the main treatment modality. Given the life-threatening size of the tumor, emergency surgical resection is inappropriate; without a confirmed diagnosis, it risks fatal hemodynamic instability from uncontrolled catecholamine release. In addition, biopsy could provoke a catecholamine surge and is contraindicated in suspected PGL. The patient received adequate volume expansion, pharmacologic control of blood pressure and heart rate, and oral alpha-1 adrenergic receptor blockade prior to hepatic hilar mass resection. Ultimately, the giant tumor was successfully excised. Postoperative recovery was uneventful, and the vital signs returned to normal. Plasma catecholamine levels progressively declined to normal, and other abnormal biochemical parameters were normalized. Histopathological examination confirmed the diagnosis of PGL (Figure 2A), with a low Ki-67 proliferation index (1%) (Figure 2B) and positive staining for succinate dehydrogenase subunit B (SDHB) (Figure 2C).

Figure 2.

Photograph of the tumor, H&E and IHC stained images. (A) H&E stained images (4× and 20× magnification). (B) Ki-67 stained images (4× and 20× magnification). (C) SDHB stained images (4× and 20× magnification). (D) Photograph of the tumor after surgery (unit of length: inch). H&E, hematoxylin and eosin; IHC, immunohistochemical.

The blood pressure normalized 7 days after discharge. At the 3-month postoperative follow-up, the patient remained asymptomatic. Follow-up hematological investigations were within the normal range, with the most recent assessment performed on September 1, 2025. All procedures performed in this study were in accordance with the ethical standards of the institutional and/or national research committee(s) and with the Declaration of Helsinki and its subsequent amendments. Written informed consent was obtained from the patient for publication of this article and accompanying images. A copy of the written consent is available for review by the editorial office of this journal.

Discussion

Acute abdomen is very common in surgical outpatient consultations. However, the unusual aspect of this case lies in the fact that the patient not only presented with a critical condition but also required the identification of a rare functional mass and the diagnosis and analysis of a hereditary disease. This case highlights a rare (incidence of 0.2–0.8 per 100,000 population per year) (1) but potentially life-threatening presentation: a functional PGL in a young patient with NF1 manifesting as acute abdomen and persistent hypertension. PGL can cause uncontrolled catecholamine release, leading to stroke, myocardial infarction, or arrhythmias if mismanaged. The prevalence of PGL in patients with NF1 is thought to be 0.1–5.7% (2), significantly higher than that in the general population, due to the autosomal dominant mutation in the NF1 gene, which predisposes patients to develop neuroendocrine tumors. Hypertension should prompt an evaluation for catecholamine-secreting tumors, as undetected PGLs carry a high mortality risk during unrelated procedures (3).

The patient’s presentation of hypertensive emergency with nonspecific abdominal pain necessitated urgent biochemical testing (plasma metanephrines) followed by targeted imaging (CT or MRI). Two critical principles guide the management of this condition. First, any NF1 patient with hypertension requires prompt screening for catecholamine-secreting tumors, with biochemical testing preceding imaging due to its higher sensitivity. Second, large tumors (>5 cm) substantially increase the risks of surgery, as they can release catecholamines at 5- to 10-fold baseline levels (4,5). This patient’s 9.6-cm tumor (Figure 2D) necessitated meticulous preoperative preparation, including at least 14 days of α-adrenergic blockade with aggressive volume expansion, monitored via orthostatic blood pressure to ensure hemodynamic stability.

The endocrinology team managed α- and β-blockade while addressing hypercalcemia to prevent hypocalcemia during tumor resection. The surgery involved tumor dissection with stepwise vessel ligation to minimize catecholamine release. Pathologic examination confirmed PGL with positive SDHB expression, indicating 40–50% metastatic risk, warranting germline SDHx testing and lifelong biennial surveillance (6). The low Ki-67 index suggested a less aggressive tumor, but long-term monitoring remained essential due to NF1’s predisposition to multiple neoplasms.

This case reinforces the need for heightened suspicion of PGL in NF1 patients with hypertension, especially when tumors or endocrine disorders are detected, as delays in diagnosis or inappropriate interventions can precipitate catastrophic outcomes. Clinicians must prioritize biochemical testing, tailored preoperative management, and multidisciplinary collaboration to optimize outcomes in this high-risk population.

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Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. All procedures performed in this study were in accordance with the ethical standards of the institutional and/or national research committee(s) and with the Declaration of Helsinki and its subsequent amendments. Written informed consent was obtained from the patient for publication of this article and accompanying images. A copy of the written consent is available for review by the editorial office of this journal.