<s>[INST] May you please explain to me what this is: Exam: MRI brain and sella with and without contrast History: hyperprolactinemia galactorrhea irregular menses Findings: the pituitary gland is slightly heterogeneous in signal. There may be a tiny, 1mm hypoenhancing lesion in the posterior pituitary gland just right of midline. Microadenoma is a possibility given the history the pituitary gland is otherwise unremarkable there is no parasellar or suprasellar mass lesion the pituitary stalk is midline The ventricles are normal in size and morphology there is no hemorrhage infarction and demyelination there is no midline shift or extra axial collection Mild mucosal thickening is noted in the left maxillary sinus [/INST] Hi, I am Chat Doctor.  I have read your question with care and understand your concerns. Let me try to help you Question : What does mild mucosal thickening in the maxillary sinus mean? Answer : For your Complaints of hyperprolactinemia galactorrhea irregular menses, the mild mucosal thickening in the maxillary sinus does not mean anything. So you need not worry about that However, what is important for you is the "tiny, 1 mm hypo enhancing lesion in the posterior pituitary gland just right of midline" which can well be the cause of galactorrhea and irregular menses. I would suggest that you evaluate this further Hope you found the answer helpful. If you need any clarification / have doubts / have additional questions / have follow-up questions, then please do not hesitate in asking again. I will be happy to answer your questions. Let me know if I can assist you further. Take care ! </s>