Pancreatic carcinoid: an unusual tumour in an uncommon location.
S Prasad, T Patankar, A Joshi, H Deshmukh
Department of Radiology, Seth G. S. Medical College, Mumbai, India., India
Department of Radiology, Seth G. S. Medical College, Mumbai, India.
Primary pancreatic carcinoid is an extremely rare pancreatic neoplasm. It differs from other primary pancreatic tumours in cytoarchitecture, immunocytochemistry and biologic behaviour. Recognition of this rare entity is of vital importance having considerable therapeutic and prognostic implications. We report a case of an exophytic, pancreatic body carcinoid tumour in a man who presented with abdominal pain. The diagnosis was established by histopathological examination of the core biopsy specimen. A surgical resection of the lesion was done successfully and the patient made a satisfactory recovery from the operation.
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Prasad S, Patankar T, Joshi A, Deshmukh H. Pancreatic carcinoid: an unusual tumour in an uncommon location. J Postgrad Med 1998;44:97-8
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Prasad S, Patankar T, Joshi A, Deshmukh H. Pancreatic carcinoid: an unusual tumour in an uncommon location. J Postgrad Med [serial online] 1998 [cited 2022 Jun 30 ];44:97-8
Available from: https://www.jpgmonline.com/text.asp?1998/44/4/97/365
Most of the pancreatic carcinomas (95%) originate in the exocrine portion; ductal adenocarcinomas account for 85% of all pancreatic cancers. Pancreatic endocrine neoplasms constitute a minority of primary pancreatic neoplasms. Pancreatic carcinoid is an extremely rare, neuroendocrine tumour arising from Kultschitsky’s (serotonin secreting) cells normally present in association with the exocrine ducts. Only few isolated reports documenting primary pancreatic carcinoid tumours exists,. Pancreatic carcinoid is indistinguishable from epithelial neoplasms clinically and on imaging studies. Biopsy is essential to establish the diagnosis.
A 35-year-old male presented with history of dull, epigastric pain for two months. The clinical examination was unremarkable. The laboratory investigations were normal. Carcinoembryonic antigen level was normal. An ultrasonography of the abdomen showed an exophytic mass lesion (isoechoic to pancreas) in the pancreatic body. Plain and contrast enhanced computerized tomographic (CT) scan of the abdomen showed a well circumscribed, exophytic mass in the pancreatic body [Figure:1]. The mass showed relatively homogeneous contrast enhancement with central hypodensity. There was no calcification. Rest of the pancreas was normal. There was no abdominal lymphadenopathy. Liver, spleen, kidneys, adrenals were normal. Histologic examination of the specimen obtained by core biopsy revealed islands of round cells with eosinophilic cytoplasm and prominent nuclei. Some of the tumour cells conformed to the glandular pattern of arrangement. Psammoma bodies were also recognized [Figure:2]. Serotonin secretory granules were identified within the cells suggestive of carcinoid tumour. Complete surgical resection of the exophytic mass was done. The patient made an uneventful recovery from the operation and was discharged in a stable condition.
Although pancreas is an uncommon location for a carcinoid tumour, the complex cell population of the pancreas may give rise to a large group of endocrine tumours with pluripotential secretory capabilities. Pancreatic body and tail constitute common sites of pancreatic endocrine tumours correlating with greater islet cell concentration in these locations. Pancreatic carcinoid is a rare neuroendocrine tumour originating in the enterochromaffin cells and excreting serotonin derivatives. Immunohistochemically, tumours are positive for panendocrine markers like neuron specific enolase, synaptophysin, chromogranin and specific markers like serotonin and its metabolites.
Carcinoid tumours most commonly arise in the midgut organs, less commonly in hindgut organs and rarely in organs derived from embryonic foregut. The location of the carcinoid and the tumour size represent two important factors determining the metastazing potential of the carcinoid tumours. Though carcinoid tumours are slow growing, foregut carcinoids are considered biologically more aggressive. While tumours less than 1 cm metastazises in less than 2% of cases, tumours more than 2 cm present with metastases in over 80% of cases. The colonic carcinoids exhibit the maximum potential to metastasize with mete stases occurring in 6070% of tumours. In contrast, though the appendix constitutes the commonest site of carcinoids, only 23% of the appendicular carcinoids have metastases at presentations. Carcinoid tumours commonly metastasize to regional lymph nodes and liver. Uncommonly widespread metastases to the brain, breast and bone can occur.
Pancreatic carcinoids usually present with carcinoid syndrome. Carcinoid syndrome occurs in a majority of patients with liver metastases and consists of the classic triad of cutaneous flushing, diarrhoea and valvular heart disease. However the absence of the characteristic carcinoid syndrome does not exclude the diagnosis of carcinoid tumour even in patients with liver metastases. Hiller et al described two patients with liver metastases in patients with pancreatic carcinoids who did not have carcinoid syndrome. Some tumours cause subacute ductal obstruction leading to chronic, recurrent pancreatitis. Gettenberg et al described a young woman with a pancreatic carcinoid tumour who presented with chronic pancreatitis associated with pseudocyst formation. The variegated imaging findings of pancreatic carcinoids are non-specific and reflects tissue heterogeneity. Usually they appear as well circumscribed, homogenous tumours occurring in the pancreatic body or tail. Large tumours are heterogenous with areas of necrosis.
Calcification in these tumours is unusual. Primarily cystic carcinoids are exceptionally seen. The radiologic findings are not pathognomonic and hence biopsy and histological examination is essential to establish the definitive diagnosis. In conclusion, the diagnosis of pancreatic carcinoid has to be considered in the differential diagnoses of pancreatic neoplasms. Recognition of this entity is important as it has better prognosis than the adenocarcinomas if detected early and effective treatment is available to combat the distressing symptoms due to carcinoid syndrome.
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