A new comprehensive grading for giant pituitary adenomas: SLAP grading

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.

Automated summary

The study developed a new grading system for giant pituitary adenomas and found that a total score of >= 5 was associated with subtotal resection.