Neuroendocrine tumors producing calcitonin: characteristics, prognosis and potential interest of calcitonin monitoring during follow-up

Abstract

Objectives: Inappropriate calcitonin (CT) release, a major feature of medullary thyroid cancer (MTC), may occur in neuroendocrine tumors (NETs). The aims of this retrospective study were to assess i) the characteristics and prognosis of CT-producing NETs, and ii) the value of CT monitoring during follow-up. Methods: All patients with NETs in whom serum CT was assayed between 2010 and 2012 were included. MTCs were excluded. Clinical, biological, and histological characteristics were studied. Results: Twenty-one (12%) of 176 patients in whom serum CT was systematically assayed had concentrations O100 ng/l, with tumours predominantly of bronchial or pancreatic origin (P!0.0001), and of high grade (PZ0.0006). Poor prognosis was linked to high CT levels, poor differentiation, and grade 3. In a total group of 24 patients with serum CT O100 ng/l, symptoms potentially attributable to CT were recorded in eight, with occasional overlap with the carcinoid syndrome among other secretory syndromes. Immunohistochemistry could be performed in six tumor specimens, CT being detected in five. In 11 patients with five or more successive CT assays, hormone levels were fairly well correlated with clinical courses. Conclusion: Serum CT levels may be raised in some patients with NETs, especially from foregut origin, and of high grade. The suggested value of CT monitoring during follow-up must be confirmed in further studies.

Calcitonin-Secreting Pancreatic Neuroendocrine Tumor in a Patient with Multiple Endocrine Neoplasia Type 1

“…With several pancreatic lesions noted on imaging, this pattern was highly suggestive of ectopic pancreatic calcitonin secretion. lungs, thymus, small intestine, liver, and bladder (8). Despite the abnormal secretion of calcitonin, up to one half of patients with tumors that produce the hormone may be asymptomatic (4,6,7,16,18).…”

“…Despite the abnormal secretion of calcitonin, up to one half of patients with tumors that produce the hormone may be asymptomatic (4,6,7,16,18). Classically, high circulating calcitonin levels are associated with medullary thyroid carcinoma, but may also be elevated in patients with chronic kidney disease, especially those with secondary hyperparathyroidism (6)(7)(8)16). Our patient had previously been operated on and found to have C cell hyperplasia, which can produce watery diarrhea, abdominal pain, and flushing, and is best treated surgically, as he was.…”

“…Higher levels of calcitonin are considered to correlate with the presence of symptoms, but not all patients with high levels of the hormone will have symptoms (6)(7)(8)16,18). When symptoms do occur, the main manifestations of calcitonin-secreting PNETs are watery diarrhea (51.4%), abdominal pain (35.1%), and weight loss (6,7,16).…”

“…Most patients with calcitonin-producing PNETs (59.5 to 90%) are reported to present with metastatic spread at the time of diagnosis (6,8,11,19). Despite knowledge of our patient's MEN1 status, which prompted early monitoring and intervention, our patient was noted to have spread to a peripancreatic node.…”

“…Very rare instances of calcitonin-secreting PNETs have been reported, with those being associated with familial syndromes such as MEN1 being rarer still (6,7). This being such a rare entity, there is a paucity of data on which to base management (1,(8)(9)(10)(11). We present a case of a calcitonin-secreting PNET in a patient with known MEN1, discuss management, and review the scant literature.…”