T2-weighted MRI signal intensity of a somatotroph PitNETs-assessed with quantitative and qualitative methods- how our predictions are verified in the histopathological examination?

Magdalena Godlewska; Anna Grochowska; Anna Bogusławska; Grzegorz Zielinski; Dariusz Adamek; Maria Maksymowicz; Alicja Hubalewska-Dydejczyk; Aleksandra Gilis-Januszewska

doi:10.1530/endoabs.99.P339

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Endocrine Abstracts (2024) 99 P339 | DOI: 10.1530/endoabs.99.P339

ECE2024 Poster Presentations Pituitary and Neuroendocrinology (120 abstracts)

T2-weighted MRI signal intensity of a somatotroph PitNETs-assessed with quantitative and qualitative methods- how our predictions are verified in the histopathological examination?

Magdalena Godlewska ¹ , Anna Grochowska ² , Anna Bogusławska ¹ , Grzegorz Zielinski ³ , Dariusz Adamek ⁴ , Maria Maksymowicz ⁵ , Alicja Hubalewska-Dydejczyk ¹ & Aleksandra Gilis-Januszewska ¹

Err

Author affiliations

¹Jagiellonian University Medical College, Department of Endocrinology, Cracow, Poland; ²Jagiellonian Uniersity Medical College, Department of Radiology, Cracow, Poland; ³Military Institute of Medicine, Department of Neurosurgery, Warsaw, Poland; ⁴Jagiellonian University Medical College, Department of Pathomorphology, Cracow, Poland; ⁵Maria Sklodowska-Curie National Research Institute of Oncology, Department of Cancer Pathomorphology, Warsaw, Poland

Aim: To investigate T2-signal intensity (SI) and histopathological characteristics of the somatotroph PitNETs (S-PitNET).

Methods: 41 out of 109 consecutive patients with newly diagnosed acromegaly and available histopathological results were included. 36 results contained the electron microscope examination. Tumors were divided into 3 SI groups: hyperintensive (HyPER), isointensive (ISO) and hypointensive (HyPO). SI was assessed qualitatively using Visual Method (visual comparison between S-PitNET and white and grey matter of the temporal lobe (WM and GM, respectively) and quantitatively by measurement of SI within the Region of Interest in the solid part of S-PitNET and in the WM and GM. Relative Signal Intensity (rSI, calculated ratio of S-PitNET’s SI and the SI of GM) ≤0.8 classified S-PitNET as HyPO, >0.8 but <1.2 as ISO, ≥ 1.2 as HyPER. Three Tissue Method classified tumors with SI equal or lower to WM as HyPO, with SI equal or higher than GM as HyPER, while the remaining tumors were classified as ISO.

Results: 31.7% of tumors expressed only GH, 17.1% co-expressed GH and PRL, other S-PitNETs expressed GH and at least one hormone other than PRL (the most frequent combination: GH, PRL, alpha subunit). We found no differences between HyPER, ISO and HyPO in hormone expression. In electron microscope 58.3% of tumors were classified as densely granulated, 27.8% as sparsely granulated and 13.9% as bihormonal. According to Visual Method and rSI HyPER and ISO had both dense and sparse granulation. Bihormonal tumors presented as HyPO (60-80%) and ISO (20- 40%). According to Three Tissue Method, no HyPO specimens had sparse granulation. Ki-67<1% was the most frequent diagnosis among all tumors. None of the HyPO had Ki-67 ≥3%. Detailed results are depicted in Table 1.

Table 1 Results of electron microscope verification
Tumor type	Densely granulated	Sparsely granulated	Bihormonal
Visual Method
HyPER	72.7%	27.3%	0%	P=0.159
ISO	50%	41.7%	8.3%
HyPO	53.8%	15.4%	30.8%
rSI
HyPER	71.4%	28.6%	0%	P=0.514
ISO	52.9%	35.3%	11.8%
HyPO (n=12)	58.3%	16.7%	25%
Three Tissue Method
HyPER	64.7%	29.4%	5.9%	P=0.056
ISO	53.8%	38.5%	7.7%
HyPO	50%	0%	50%

Conclusion: Tumors manifesting as HyPER or ISO are verified in histopathological examination as both densely and sparsely granulated, regardless of SI assessment method. No HyPO tumor had sparse granulation. Interestingly, no bihormonal tumor presented as HyPER.