Clinical, biochemical and radiologic characterization of somatotroph tumors according to adenoma granulation pattern

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: SUN 88-129-Acromegaly & Prolactinoma
Sunday, June 16, 2013: 1:45 PM-3:45 PM
Expo Halls ABC (Moscone Center)

Poster Board SUN-119
Carmen A Carrasco*1, Pablo Villanueva1, Roger Gejman1, David Rojas Z2, Isidro Huete1, Romina Zunino1, René Diaz3, Claudia Tissera4 and Nelson Wohllk3
1Pontificia Universidad Católica de Chile, Santiago, Chile, 2Universidad de Chile, Instituto de Neurocirugía, Santiago, Chile, 3Universidad de Chile Sede Oriente, Santiago, Chile, 4Instituto de Neurocirugia, Santiago, Chile
Somatotroph adenomas typically manifest as acromegaly and have been structurally classified as densely granulated (DG), sparsely granulated (SG) and intermediate (M) according to intracytoplasmic distribution of citokeratins (CK). Evidence suggests that SG tumors could have more aggressive biological behavior.

OBJECTIVES: To compare the clinical, biochemical, radiological presentation and surgical outcome among different histological subtypes of somatotroph adenomas.

MATERIALS AND METHODS: Cohort of 77 somatotroph adenomas operated between 2005 and 2012. The criteria of remission were normal IGF1 and/or GH nadir < 0.4 ng/ml at 3-6 months. RIGF1 was defined as the relation between IGF1 of patient and upper normal value. Two independent radiologists evaluated tumor size and cavernous sinus invasion. Tumor was considered invasive if Knosp grade was >3. We performed a tissue microarray and immunohistochemistry for GH and CK, classifying tumors as DG, SG or M by a blinded pathologist. Continuous variables are expressed as median [range]. The c2test was used to compare qualitative variables and Mann−Whitney test to compare quantitative variables.

RESULTS: Fifty nine % of patients were female with an average of 43 years old [range 6-71], 64% were macroadenomas and 43% invasive. Remission was observed in 46% of patients. We found that 73% of adenomas were DG, 17% SG and 10% M. No differences were found between DG and M in clinical, biochemical, radiological presentation or outcome and they were grouped as non-sparsely granulated adenomas (non-SG). Clinically, there were no significant differences between SG and non-SG in age and gender. Biochemically, there were no differences in basal GH (9.29 ng / mL [0.56-40] v/s 16.55 ng/mL [1.9-180], p = 0.3), nadir GH (5.7 ng/ml [0.4-40] v / s 11.4 ng / mL [1.61-138], p = 0.1) or rIGF1 (2.09 ng/ml [1.06 -7.08] v/s 2.47 [1.04-5.97, p = 0.5). Radiologically, SG were more frequently macroadenomas (100% v/s 56%, p = 0.010) and invasive (84.6% v/s 34%, p = 0.004). Concerning surgical outcome, size (p 0.01) and invasion (p 0.01) were associated to persistence of disease and no differences were found between SG and non-SG tumors (36% were cured by surgery v / s 47%, p = 0.3). CONCLUSIONS: These findings support that SG-type adenoma is a distinct section of somatotroph tumors, especially with more aggressive radiological presentation. Long term following will inform about implications in recurrence of acromegaly and prognosis.

Nothing to Disclose: CAC, PV, RG, DR, IH, RZ, RD, CT, NW

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