MRI and Trouillas' grading system of pituitary tumors: the usefulness of T2 signal intensity volumetric values

Clinical and prognostic implications of pituitary macroadenomas (PitNets) grading: a monocentric experience

RATIONALE

Pituitary neuroendocrine tumors (PitNets), also known as pituitary adenomas, are aggressive in 20% of cases, with local invasion, relapse/scarce response to conventional treatment, in the absence of reliable predictive parameters. In 2018, Trouillas et al. proposed a 5-tier clinicopathological classification, not widely validated yet. In the present study we investigated, in a PitNets monocentric series, the correlation between this classification system and features at diagnosis and medium-term clinical and biochemical outcomes.

MATERIALS & METHODS

we retrospectively evaluated 88 consecutive patients (51 M, 50.5±14.7 yrs) with functioning (FPA) or non-functioning pituitary macroadenomas (NFPA), referred to the Endocrine Unit of Messina University Hospital, and operated by the same neurosurgeon in the period 2015-2020. Of each patient we reviewed recorded demographic, clinical, radiological, biochemical data and visual field, both at diagnosis/last follow-up (median 3 ± 1.5 yrs), therapeutical history, and pathological data. Once classified PitNets according to Trouillas et al. grading system, we correlated it to clinico-pathological and hormonal features at diagnosis, and to clinical, biochemical and ophthalmological outcomes at 6 months after surgery and at last follow-up.

RESULTS

According to Trouillas grading system, 38.6% of patients were assigned the 1a grade, 7.9% the 1b, 48.9% and 4.5% the 2a and 2b, respectively. At diagnosis, panhypopituitarism and visual field alterations were more frequent among 2a grade tumors. GH-omas were significantly prevalent among 1a tumors, NFPA among 2a. PitNets with 1a and 2a grade had a better response to single surgery (p < 0.01), while cyberknife stereotactic radiotherapy was needed more frequently in 2a and 2b tumors. Panhypopituitarism/visual field alterations were more frequent among 2a PitNets even after surgery. Ki-67 was positively associated to persistent disease in FPA, while radiological invasion was associated to remnant presence among NFPA.

CONCLUSIONS

Invasive and not-proliferating PitNets (2a) were more frequently associated to impaired pituitary function/visual field before and after surgery. Less proliferating tumors (1a and 2a) were more responsive to surgery. Ki-67 correlated to disease persistence in FPA, while adiuvant radiotherapy was more needed among invasive tumors. Thus, among ≥ 1 cm PitNets, tumor invasion seems to impact on clinico-biochemical outcomes, while Ki-67 proliferation index influences surgical outcomes.

Trouillas's Grading and Post-Surgical Tumor Residue Assessment in Pituitary Adenomas: The Importance of the Multidisciplinary Approach

BACKGROUND

We aim to assess the role of a multidisciplinary approach in pituitary adenomas (PitNETs) classification, evaluate criteria concordance, and compare intraoperative assessments with post-operative MRIs for tumor remnants.

METHODS

Clinical, radiological, histological, and intra- and post-operative data of the treated PitNETs were extracted from prospectively created records. PitNETs were graded according to Trouillas, and the evaluation of the tumor remnants was recorded.

RESULTS

Of 362 PitNETs, 306 underwent surgery, with Trouillas grading assigned to 296. Eight-nine radiologically non-invasive PitNETs progressed to grades 1b (27), 2a (42), or 2b (20) due to proliferative or surgical invasiveness criteria. Twenty-six radiologically invasive tumors were graded 2b due to proliferative criteria. Surgical resection details and post-surgical MRI findings revealed that residual tumors were more common in grades 2a and 2b. During surgery, small tumor remnants were documented in 14 patients which were not visible on post-surgical MRI. Post-surgical MRIs identified remnants in 19 PitNETs not seen during surgery, located in lateral recesses of the sella (4), retrosellar (2), or suprasellar regions (7), along the medial wall of the cavernous sinus (6).

CONCLUSIONS

The Pituitary Board allows for the correct grading of PitNETs to be obtained and an accurate identification of high-risk patients who should undergo closer surveillance due to tumor remnants.