G Occhi, G Trivellin, F Ceccato, P De Lazzari, G Giorgi, S Demattè, F Grimaldi, R Castello, M V Davì, G Arnaldi, L Salviati, G Opocher, F Mantero and C Scaroni
Germline mutations in the aryl hydrocarbon receptor-interacting protein (AIP) gene and the p27KIP1 encoding gene CDKN1B have been associated with two well-defined hereditary conditions, familial isolated pituitary adenoma (FIPA) and multiple endocrine neoplasia type 4 (MEN4). Somatotropinomas are present in most AIP mutated FIPA kindreds, as well as in two-thirds of MEN4 patients who carry pituitary tumors.
Germline DNA samples of 131 Italian sporadic acromegalic patients including 38 individuals with multiple tumors, and of six FIPA families (four homogeneous for prolactinomas and two heterogeneous with prolactin/nonfunctioning pituitary adenomas) were collected in a multicentric collaborative study. The prevalence of AIP and CDKN1B gene point mutations and copy number variations were evaluated.
Two novel (IVS3+1G>A and c.871G>A) and one previously described (c.911G>A) AIP mutations were detected in four apparently sporadic cases (3.1%) with relatively high age at diagnosis (49±18, range 30–67). No mutations/rearrangements were detected in FIPA families. The highly conserved c.871G>A substitution was detected in a patient who also carried a MEN1 mutation suggesting that she is a double heterozygote. The possible pathogenic effect on AIP splicing of the silent substitution c.144G>A found in another patient was ruled out using a minigene-based approach. CDKN1B mutations/rearrangements were neither identified in patients with multiple neoplasia nor in FIPA families.
AIP is mutated in about 3% of apparently sporadic acromegalic patients. The relatively high age at diagnosis, as well as its sporadic presentation, suggests that these patients are carriers of mutations with reduced pathogenicity. p27KIP1 is unlikely to represent the common unifying nonendocrine etiology for acromegaly and cancer.
A Veltroni, E Cosaro, F Spada, N Fazio, A Faggiano, A Colao, S Pusceddu, M C Zatelli, D Campana, A Piovesan, A Pia, E M Grossrubatscher, A Filice, A Bianchi, P Razzore, M Toaiari, S Cingarlini, L Landoni, R Micciolo and M V Davì
Management of malignant insulinomas is challenging due to the need to control both hypoglycaemic syndrome and tumor growth. Literature data is limited to small series.
Aim of the study
To analyze clinico-pathological characteristics, treatments and prognosis of patients with malignant insulinoma.
Materials and methods
Multicenter retrospective study on 31 patients (male: 61.3%) diagnosed between 1988 and 2017.
The mean age at diagnosis was 48 years. The mean NET diameter was 41 ± 31 mm, and 70.8% of NETs were G2. Metastases were widespread in 38.7%, hepatic in 41.9% and only lymph nodal in 19.4%. In 16.1% of the cases, the hypoglycaemic syndrome occurred after 46 ± 35 months from the diagnosis of originally non-functioning NET, whereas in 83.9% of the cases it led to the diagnosis of NET, of which 42.3% with a mean diagnostic delay of 32.7 ± 39.8 months. Surgical treatment was performed in 67.7% of the cases. The 5-year survival rate was 62%. Overall survival was significantly higher in patients with Ki-67 ≤10% (P = 0.03), insulin level <60 µU/mL (P = 0.015) and in patients who underwent surgery (P = 0.006). Peptide Receptor Radionuclide Therapy (PRRT) was performed in 45.1%, with syndrome control in 93% of patients.
Our study includes the largest series of patients with malignant insulinoma reported to date. The hypoglycaemic syndrome may occur after years in initially non-functioning NETs or be misunderstood with delayed diagnosis of NETs. Surgical treatment and Ki67 ≤10% are prognostic factors associated with better survival. PPRT proved to be effective in the control of hypoglycaemia in majority of cases.