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Neuroendocrine tumours are reported from the alimentary and respiratory tracts. A case of a 57‐year‐old man with an unsuspected histopathological finding of neuroendocrine tumour cells in the wall of a splenic artery aneurysm is reported.
Visceral artery aneurysms are uncommon but clinically important owing to the risk of rupture and of intra‐abdominal bleeding.1 There are several possible aetiologies, atherosclerosis being one, and often the cause is unknown or at least not stated.1 The case of a patient with two visceral artery aneurysms and unsuspected histopathological finding is reported.
A 57‐year‐old man presented with a 24 h history of increasingly severe upper abdominal pain. As an infant, he was operated on for an open Botalli duct. At the age of 20 years, he was conservatively treated for a pyloric ulcer. For the previous 2 years, he had been taking drugs for depression. On admission to hospital, his abdomen was tender with general guarding. A contrast‐enhanced CT scan showed a splenic artery aneurysm and a mass in the pyloric region suspected as a ruptured visceral aneurysm. Both lesions were about 7 cm in diameter. An emergency laparotomy showed free blood in the peritoneal cavity and an upper right retroperitoneal haematoma.
A ruptured aneurysm of the right gastroepiploic artery was resected en bloc with a part of the antrum and colon. Histopathological examination showed atherosclerosis in the wall of the aneurysm and chronic gastritis in the antrum. An elective operation was performed 4 months later and the splenic artery aneurysm repaired by proximal and distal ligation. A representative part of the splenic artery aneurysm was resected and fixed in formalin for histopathological examination.
Blood and urine samples were obtained postoperatively for hormonal and polypeptide evaluation (table 11).). Values for plasma chromogranin A and urinary 5‐hydroxyindoleacetic acid were slightly increased. The increased level of serum gastrin was explained by the patient's chronic gastritis.
Further investigations, including upper gastrointestinal endoscopy, colonoscopy, contrast x ray investigation of the small intestine and MRI (Octrescan)–somatostatin receptor scintigraphy were performed and found to be normal.
A capsule endoscopy showed two polypoid tumours located in the jejunum. A third laparotomy was performed 10 months after the first operation with peroperative endoscopy of the small intestine. The polypoid tumours were benign lymphangiomas. The appendix was normal at inspection.
The histopathological examination of the resected part of the splenic artery aneurysm showed atherosclerosis, fibrosis and chronic inflammation. Furthermore, the microscopical examination showed a discrete finding of some divergent cells in small groups and rows in the muscularis layer of the aneurysm wall, suggesting tumour impression (fig 11).
Immunohistochemical staining of the tumour cells showed positivity for cytokeratin AE1/AE3 (DakoCytomation, Glostrup, Denmark), synaptophysin (DakoCytomation) and chromogranin (Ventana Medical Systems, Arizona, USA, fig 22),), supporting the diagnosis of a neuroendocrine foregut type tumour. Immunohistochemical staining of tumour cells was negative for serotonin (DakoCytomation) and therefore the cells were not classic carcinoid tumour cells.
According to a new classification by the World Health Organization, the term “neuroendocrine tumours” is recommended instead “carcinoid”. Neuroendocrine tumours belong to a heterogeneous group of tumours affecting almost the entire alimentary tract as well as other organs such as the lungs and thymus.2 The traditional term “carcinoid tumour” is restricted to the subtype of serotonin‐producing neuroendocrine tumours. Neuroendocrine tumours are neoplasms that arise from mature endocrine cells or their stem cells. Our patient had neuroendocrine tumour cells identified in the wall of a splenic artery aneurysm. The diagnosis was based on characteristic morphological and immunohistochemical findings. This tumour type is obviously extremely rare, as a MEDLINE search did not reveal any previously published case of neuroendocrine tumour cells in the wall of an artery nor in an artery aneurysm.
Aneurysms of visceral arteries are rare, often of unknown aetiology. In contrast to other intra‐abdominal aneurysms, atherosclerosis is rarely the primary causative factor for splenic artery aneurysm, but considerable evidence exists to implicate hormonal and local haemodynamic factors in the development of these aneurysms.3 An association between carcinoid tumours and thoracoabdominal aneurysm has been reported previously.4
It can only be speculated whether neuroendocrine tumour cells could produce products that initiate local changes in the wall of the artery with subsequent aneurysm development. However, the most likely explanation of the finding in our patient is that the neuroendocrine tumour cells represent a micrometastasis of a still undiagnosed neuroendocrine tumour. The future strategy in this case will be reinvestigation.
Competing interests: None declared.