Differential diagnosis of calcitonin-secreting neuroendocrine carcinoma of the foregut by pentagastrin stimulation.
OBJECTIVE
This study assessed the suitability of pentagastrin stimulation in hypercalcitoninaemia for differential diagnosis of neuroendocrine carcinoma of the foregut.


METHODS
A prospective institutional study (March 1997-September 1999) was conducted involving all patients admitted to the pneumological and general surgical wards for small cell lung cancer (SCLC) or primary medullary thyroid carcinoma (MTC). Basal and stimulated serum calcitonin levels were measured using an improved immunoradiometrical assay for the monomeric form of calcitonin.


RESULTS
Increased basal calcitonin levels were noted in six non-MTC patients (one mediastinal and one laryngeal neuroendocrine carcinoma, and four SCLCs). Because of chronic renal failure, one SCLC patient had to be excluded. The remaining five non-MTC patients with normal renal function were compared to eight primary MTC patients. In terms of pentagastrin stimulation, an increase in serum calcitonin levels of less than twofold the baseline significantly correlated with both non-MTC (r=0.85; P=0.005) and SCLC (r=0.81; P=0.024). Immunostaining of tissue specimens for calcitonin was positive in the patients with mediastinal and laryngeal neuroendocrine carcinoma and in all eight patients with primary MTC, but was negative in the two SCLC patients with adequate tissue samples.


CONCLUSIONS
Irrespective of the pathophysiological background, pentagastrin stimulation affords a differential diagnosis in neuroendocrine carcinoma of the foregut when chronic renal failure is excluded.
Machens
A
A
Department of General Surgery, Martin Luther University Halle-Wittenberg, Germany. gensurg@medizin.uni-halle.de
Haedecke
J
J
Holzhausen
H J
HJ
Thomusch
O
O
Schneyer
U
U
Dralle
H
H
D000368:Aged; D002116:Calcitonin / Q000378:metabolism*; D018276:Carcinoma, Medullary / Q000175:diagnosis*; D018288:Carcinoma, Small Cell / Q000175:diagnosis*; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged; D010418:Pentagastrin; D011446:Prospective Studies; D013964:Thyroid Neoplasms / Q000175:diagnosis*
D002116:Calcitonin; D010418:Pentagastrin