Presentation
Secondary amenorrhea, galactorrhea and rising prolactin (last F/U 141, now 160 ng/mL) over one year despite being on treatment. (upper level of normal is ~40 ng/mL).
Patient Data
Abnormal focal contour bulge at the left side of the pituitary gland harboring a well-defined rounded T1 hypointense focal lesion measuring 7 x 7 x 10 mm. It shows isointense signal on T2 and homogeneous hypoenhancement on T1 post-contrast sequence. Deviated pituitary stalk to the right side. There is an eccentric small cystic component with a clear fluid signal.
Left posterior parietal skull osteoma.
The patient went for trans-sphenoid endoscopic resection of the microadenoma.
Osseous tract in sphenoid bone measuring 1 x 2 cm with soft tissue density.
Bone defect at the anterior aspect of the sellar floor measuring 7 mm.
Complete nasal packing.
Left posterior parietal skull osteoma.
Case Discussion
Features are typical of a sizable pituitary microadenoma, identified by its mass effect as focal contour bulge, and deviated pituitary stalk. The most characteristic MRI signal is the post-contrast homogeneous hypoenhancement. Associated cysts are common in pituitary macroadenomas, while rare in microadenomas.