A 33-year-old male presented with a chief complaint of right hypochondrium pain, which began as episodic pain one year prior. The pain was described as sharp and radiated to the right flank, exacerbated by movement, lying on the right side, and consuming large meals. The patient denied any associated symptoms such as vomiting, diarrhea, nausea, or other gastrointestinal complaints. His past medical history was notable for mild Irritable Bowel Syndrome (IBS), with episodes typically triggered by the consumption of legumes and large quantities of bread. The patient had a surgical history of splenectomy at age seven following a traumatic accident. He was a daily waterpipe smoker for five years but had no history of alcohol use, drug use, allergies, or family history of significant medical conditions. His weight and appetite were within normal limits.

On admission, the patient’s vital signs were as follows: pulse rate of 80 beats per minute, blood pressure of 130/80 mmHg, body temperature of 37.6 °C, and blood oxygen saturation (SpO2) of 98%. Clinical examination revealed a midline abdominal scar consistent with previous surgery, along with tenderness in the right upper quadrant and right flank, without rebound tenderness. The rest of the physical examination was unremarkable.

Laboratory investigations showed hemoglobin)Hgb( 15.5 g/dL, white blood cell count) WBC( 6.12 × 10⁹/L, granulocytes percentage) Gran%( 62.4%, platelet count) Plt( 331 × 10⁹/L, sodium)Na( 137 mmol/L, potassium (K( 4.3 mmol/L, Glucose 98 mg/dL, Urea 24 mg/dL, Creatinine 0.8 mg/dL, prothrombin time (PT) 13.7 s, activity 96%, and international normalized ratio (INR) 1.02 (see Table 1).

An ultrasound of the abdomen and pelvis was performed, which revealed lobulated mass at the anatomical location of the right adrenal gland, measuring 4.5 × 5 cm, with an isoechoic to hypoechoic texture. Doppler ultrasound was inconclusive for vascular assessment of the mass. Additionally, a similar 2 cm mass was identified near the porta hepatis, though its precise nature could not be determined. Several oval-shaped lymph nodes were detected, with the largest on the left side measuring 3 × 8.5 mm and on the right side measuring 6.5 × 16 mm. Lymph nodes with a fatty core were also observed around the femoral vessels, the largest on the right measuring 19 × 9 mm and on the left 12.5 × 7 mm. Importantly, there was no significant enlargement of lymph nodes around the iliac or axillary vessels.

Given these findings, the patient was prepared for further evaluation, a multi-slice computed tomography (MSCT) scan with contrast injection was performed, revealing multiple nodules in the right adrenal gland. These nodules were defined, regular in shape, and appeared to exert a compressive mass effect on the adrenal gland, possibly representing lymph node aggregation or metastasis. Additionally, significant lymphadenopathy was noted around the abdominal aorta (see Fig. 1).

Abdominal and Pelvic MsCT revealed tissue nodules in the anatomical area of the spleen. These nodules exhibit clear equivalent density, regular borders, and overlapping. The largest nodule measures 3.5 cm and appears to represent a lymph node as an additional splenic differential diagnosis. Additionally, on the right adrenal, several tissue nodules are tangential to the lateral peduncle, isolated from the medial peduncle, exerting a compressive mass effect. Lymphadenopathy is also observed around the abdominal aorta

Based on these imaging findings, the patient was referred to an endocrinologist before any surgical intervention. Urinary catecholamine metabolite levels were measured, showing metanephrine levels of 247.5 µg/24 h (normal range: < 350 µg/24 h) and significantly elevated normetanephrine levels of 1158 µg/24 h (normal range: < 600 µg/24 h), raising suspicion of an extra-adrenal pheochromocytoma. Other differential diagnoses included benign neoplastic lesion and adrenal cancer.

Consequently, the decision was made to proceed with laparoscopic surgery for biopsy and adrenalectomy, along with excision of the surrounding mass (see Supplementary Video 1). Informed written consent was obtained from the patient, who remained hemodynamically stable throughout the preoperative period without hypertensive episodes. The surgical procedure was uneventful, with intraoperative blood pressures averaging 110/80 mmHg, and no arrhythmias were observed. The resected specimens were sent for histopathological examination, which revealed the presence of three accessory spleens exhibiting signs of congestion. Additionally, the excisional biopsy of the abdominal mass confirmed normal right adrenal gland tissue, which was surrounded by abundant adipose tissue. A reactive lymph node was also identified, with no evidence of malignancy (see Fig. 2).

Anterior and posterior views of the resected specimen showing multiple masses excised en bloc from the peritoneum. The anterior view displays masses identified as accessory spleens located in front of the kidney, while the posterior view highlights the excised adrenal gland along with surrounding adipose tissue, attached to the peritoneum

Postoperatively, the patient was monitored in the intensive care unit and remained stable, with the chest tube being removed prior to discharge. During a week-long hospital stay, the patient exhibited stable vital signs without any notable complications. The final diagnosis was three accessory spleens. He was discharged after one week with follow-up scheduled.