Rathke's cleft cyst
Visual field defect.
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The pituitary gland is enlarged by a non-enhancing well circumscribed lesion which extends above the diaphragma sella and impinges upon the optic chiasm.
Note: On fat sat T1 C+ images it is difficult to distinguish intrinsic T1 from enhancement. Looking at the non fat sat T1 C+ coronals confirms lack of enhancement.
Features therefore suggest the diagnosis of a Rathke's cleft cyst or adamantinomatous craniopharyngioma although the absence of calcification and age make this less likely. A necrotic adenoma is another possibility.
The patient went on to have surgery which confirmed the diagnosis of a non-tumour cyst, presumably a Rathke's cleft cyst.
MACROSCOPIC DESCRIPTION: "Cyst wall": A small fragment.
MICROSCOPIC DESCRIPTION: The sections show extremely small fragments of anterior pituitary tissue in each of the two specimens submitted. These show infiltration by small lymphocytes and monocyte-macrophages. No evidence of tumour is seen in either specimen.
FINAL DIAGNOSIS: Cyst wall & contents: Small fragments of unremarkable anterior pituitary tissue; no evidence of tumour seen.
The patient has been followed up for a number of years without recurrence.
This case also highlights the difficulty in correctly identifying presence of enhancement, particularly on fat sat T1 C+ Images; they are great for delineating the extent of enhancement, but can suggest enhancement is present when in fact none is. Read a more complete discussion here.