Spontaneous retroperitoneal abscess as the first clinical manifestation of a non-functioning retroperitoneal paraganglioma

Abstract

We demonstrate a novel clinical presentation of paraganglioma not described in the literature. The paraganglioma is a catecholamine secretory, or non-secretory, neuroendocrine tumour that derives from chromaffin cells. Its frequency, with regard to pheochromocytoma, is low, and the abdominal region is the most frequent localisation site, followed in importance by the cervical region. We report the case of a 54-year-old woman diagnosed with a retroperitoneal abscess; after drainage of the lesion, samples indicated necrotic paraganglioma cells, so it was decided to conduct a survey to determine catecholamine levels in urine, and carry out a MIBG gammagraphy, which described a non-functioning retroperitoneal paraganglioma that underwent surgical removal. There was no residual disease after 3-month follow-up.

The retroperitoneal paraganglioma is a neuroendocrine tumour that originates in cells of the autonomous nervous system of the extra-adrenal paraganglia that are localised along the paravertebral and para-aortic axis; these tumours are rare, particularly the non-functioning ones,¹ while those that manifest as abscess and sepsis are exceptional.

Case history

We report the case of a 54-year-old woman with no remarkable medical history who presented to the emergency department with pain in the left hypochondrium, a temperature of 37ºC, and general discomfort. During the abdominal inspection, the patient complained of pain in the left hypochondrium, while deep palpation revealed a mass in the region under examination. Blood and urine tests exhibited the following altered parameters: C-reactive protein, 19.65 mg/dl (normal 0–0.8 mg/dl); leukocytes, 17,810/mcl (normal 4800–10,800 mg/dl), with left deviation (88.5% neutrophil); platelets, 948,000/mcl (normal 130–400/mcl; and CA-125, 74.36 U/ml (normal 0–35 U/ml. The other parameters were found to be normal. Abdominal-pelvic CAT revealed a low attenuation area in the retroperitoneal zone; the mass compressed and displaced the left kidney, left suprarenal gland and the tail of the pancreas, while the aetiology remained unclear (Fig. 1). It was decided to draw blood samples in order to prepare a blood culture, establish antibiotic treatment with meropenem, 1 g every 6 h, and to undertake a complete NMR study, which confirmed a retroperitoneal abscess, although the origin was unknown (Fig. 2). It was also decided to conduct explorative lumbotomy and drainage of the abscessed zone, as well as to take samples for culture and shipment of the dried material for histological study. Four days later, cultures yielded positive results for Escherichia coli, sensitive to meropenem, so the initial antibiotic treatment was maintained. On day 5, the histological results reported a paraganglioma that included necrotic areas; immunohistochemical results were positive for vimentin, chromogranin A, synaptophysin and PS100, although negative for AL-AE3, melan-A, HMB-45, CD-34, and AML; the proliferative index determined by Ki67 was lower than 25%. In view of these results and once the infectious phase was over, the residual mass was examined through gammagraphy with the I123 MIBG technique that showed an anomalous increased radiotracer focus on a 40 mm × 45 mm mass localised in the intersection that lies below the inferior side of the tail of the pancreas, the upper pole of left kidney and left supra-renal area, which determined a retroperitoneal paraganglioma (Fig. 3). The study was complemented with two series determining urinary catecholamines, which yielded the following outcomes: adrenaline < 2 mcg/l; noradrenaline, 51.3 mcg/24 h (normal < 80 mcg/24 h); dopamine 163.4 mcg/24 h (normal < 400 mcg/24 h); vanilmandelic acid 5,5 mg/24 h (normal 0–6.7 mg/24 h), normetanephrine, 277.5 mcg/24 h (normal 105–354 mcg/24 h); and metanephrine, 50 mcg/24 h (normal 24–96 mcg/24 h. Removal of the lesion was achieved through anterior surgical approach.

Figure 1.

Abdominal-pelvic CAT: low attenuation area in retroperiton-eal zone; the mass compresses and displaces left kidney, left suprarenal gland and the tail of the pancreas.

Figure 2.

NMR: mass compatible with retroperitoneal abscess.

Figure 3.

Gammagraphy with I123 MIBG: anomalous increased radiotracer focus on a 40 mm × 45 mm mass localised in the intersection that lies below the inferior side of the tail of the pancreas, the upper pole of left kidney and left suprarenal area.

Discussion

Paragangliomas are rare tumours that originate in the extra-adrenal chromaffin tissue and represent 10–18% of tumours related to these tissues, and which have an incidence of 2–8 cases per million people/year;² retroperitoneal localisation and non-functioning tumours are very infrequent, and only around 100 cases have been described in the literature.¹ Most paragangliomas are found intra-abdominally and very close to suprarenal glands (85% of cases); intrathorax localisation is found in around 15% of cases, while cervical localisations represent 1–3% of cases, although these last two cases are not usually secretory and trigger pain by compression.³ However, Erickson et al.² reported a retrospective study of 297 paraganglioma cases localised mainly in the neck region and in the head (69.4% of cases); only in 93 cases were paragangliomas found below the neck region (30.6% of cases). This study also analysed the different presentation forms of such tumours, both in cervical and infracervical locations. The most frequent form of presentation of cervical paragangliomas was a palpable mass in 55% of cases; intracervical paragangliomas were accompanied of headache and palpitations in 20–25% of cases and represented 20–25% of cases.². None of the paragangliomas exhibited abscess and sepsis, as in our case. In 2008, Yau et al.⁴ reported a non-functioning retroperitoneal paraganglioma that presented with a spontaneous rupture and acute abdomen, which required explorative laparoscopy; the subsequent post-surgical study determined a non-functioning, para-aortic paraganglioma, eligible for elective surgery.⁴

In general, these tumours manifest most frequently in males aged 30–45 years. Most authors believe there is a relationship, which may represent 40–50% of cases, between hormone secretion from paraganglioma and the malignancy they exhibit, although other surveys did not report such findings.⁵

The diagnosis of these tumours is multifactorial and requires biochemical trials and imaging techniques. Biochemical diagnosis is aimed at determining catecholamines levels (adrenalin, noradrenalin, and dopamine) as well as their 24-h urine metabolites;⁶ sensitivity was found to be around 90%, although values can be enhanced if tumours are diagnosed together instead of separately.² As for imaging tests, MIBG gammagraphy is beyond doubt the technique that yields the highest specificity values, around 97–10%; sensitivity, though, is quite low when compared with other imaging techniques, such as CAT or NMR.^6,7 CAT techniques allow acquisition of data on the size, localisation and possible metastasis of tumours; therefore, we believe CAT is the chief imaging test of choice for patients with suspected paraganglioma.⁵

Despite the fact that paraganglioma is not a frequent disease, although it is usually a localised one, Hamilton et al.⁸ refer to two cases accompanied by metastasis that exerted compression on the spinal cord, indicating the aggressiveness of this disease and the need for a long follow-up of most patients.

The treatment of choice, after diagnostic certainty, is the complete removal of the lesion through conventional surgery or laparoscopy surgery, once blood pressure has been checked through alpha-blocking agents; the establishment of a biochemical control at 2–6 weeks after surgery is also indicated.⁵

Prognosis for this disease may vary with respect to series, but it is close to 50% at 10 years,^3,5 although it also may vary if exeresis is or is not achieved.