Introduction: 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 determined the predictability of SLAP grading on the extent of resection.
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 tumor was noted, and scored as per the SLAP system. The largest tumor
with maximum extensions in all directions has a maximum total score of 10. The subtotal
resection (STR) was defined as residual tumor volume of more than 10%. The median
score was determined and the association between individual and total score the extent
of resection was determined.
Results: A total of 103 cases of the GPAs were analyzed. All patients had a suprasellar (S)
extension, and most had a lateral 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
extension (P) 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), and p-value was 0.004 for STR.
Conclusion: The SLAP grading is a useful grading system that can be applied easily to GPAs, and
gives a complete picture of the extension of the tumor.
