A new comprehensive grading for giant pituitary adenomas: SLAP grading

Abstract

Aim

Giant pituitary adenomas are difficult to resect due to multicompartmental extension. We developed a new grading system for giant pituitary adenomas (GPAs) considering possible extension in superior, lateral, anterior, and posterior (SLAP) directions. We also related the degree of resection to the SLAP grading.

Methods

A review of case files and radiological images of patients with the GPAs defined as pituitary adenomas with a size of more than 4 cm in any dimension was done. The extent of the tumour was noted and scored as per the SLAP system. The maximum total score is 10 and represents a large tumour with maximum extensions in all directions. The subtotal resection (STR) was defined as a residual tumour volume of more than 10%. The association between individual and total score on the degree of resection was determined.

Results

A total of 103 cases of GPAs were analyzed. All patients had a suprasellar (S) extension. The lateral (L) extension was seen in 97.3% of cases. The anterior (A) extension was seen in 28 (27.2%) cases. The posterior (P) extension was seen in 45 (43.7%). Forty-eight (46.6%) had a total score of 5 or more. The STR was achieved in 64 (62.2%) cases. On regression analysis, a total score of ≥5 was associated with odds of 5.02 (1.69–14.93), p-value 0.004 for STR.

Conclusion

The SLAP grading is a comprehensive grading system that can be applied easily to the GPAs and gives a complete picture of the extension of the tumour.

Keywords:

• Pituitary adenoma
• giant pituitary adenoma
• invasive pituitary adenoma
• transsphenoidal surgery

Acknowledgements

Dr. Mini Jayan, Biostatistician, NIMHANS, Bangalore for helping with statistical analysis.

Ethics approval

EC Waiver Granted. No. NIMHANSIEC/2020-21.

Disclosure statement

No potential conflict of interest was reported by the authors.