[MEN 1 and 2: the role of diagnostic imaging]

To report the results of a retrospective study on the use of the different imaging methods in the diagnosis of type 1 and type 2 multiple endocrine neoplasias, and to provide an overall evaluation of the diagnostic yield of the various examinations performed correlating the results with the surgical findings.

The study was conducted by reviewing the data of 12 patients, of whom four with MEN1 and eight with MEN2, assessed with different imaging modalities. In the patients with MEN1 the examinations revealed 4 parathyroid hyperplasias, 4 gastro-pancreatic endocrine-secreting lesions, one hypophyseal adenoma, one bronchial carcinoid and two bilateral adrenal hyperplasias. In the patients with MEN2 the examinations revealed 6 medullary thyroid carcinomas (MTC), 4 pheochromocytomas and 3 parathyroid hyperplasias.

In MEN1 the parathyroid hyperplasias were diagnosed by scintigraphy in all four cases, whereas neck ultrasound was positive in only two cases. The gastro-pancreatic endocrine-secreting lesions were demonstrated in all four patients with CT and endoscopic ultrasound (two patients also underwent scintigraphy with octreotide, which was positive). In only one patient with MEN1 did the chest X-ray detect a bronchial carcinoma, confirmed by CT. CT also enabled identification of a single hypophyseal adenoma. The patients with MEN2 were divided into two groups: one consisting of asymptomatic patients undergoing screening following positive genetic testing and one of symptomatic patients. In the first group the imaging examinations diagnosed one MTC and three pheochromocytomas; all patients in the second group had MTC (detected by positive ultrasound and scintigraphy examinations).

Given the rarity of this condition we believe that the only statistically important finding in our series concerns the sensitivity of the imaging examinations performed in that, with adequate clinical and laboratory data, the possible problem of false positive results is exceptional. The role of diagnostic imaging in the management of patients with MEN1 and 2 is twofold: identification of the target organs of lesions suspected on the basis of clinical and laboratory findings to enable adequate medical and/or surgical treatment; staging of malignant lesions to enable correct surgical planning. In particular, our study once again highlights the diagnostic efficacy of CT for the diagnosis of pheochromocytomas and of the combination of biopsy plus ultrasound and ultrasound plus scintigraphy for the diagnosis of MTC in MEN 2. As for MEN1 spiral CT was found to have good sensitivity (66%) in localising endocrine neoplasias of the gastrointestinal tract; endoscopic ultrasound on the other hand revealed good diagnostic efficacy, showing constantly positive findings. Finally, in both pathologies we believe that the assessment of parathyroid conditions to be mainly a matter for nuclear medicine.