Magnetic resonance characterization of a long-standing pituitary abscess

Abstract

A 56-year-old male patient with panhypopituitarism is presented. Magnetic resonance (MR) examination of the pituitary region revealed a pituitary mass with markedly increased signal intensity on T1-weighted images and low signal intensity on T2-weighted images. At surgery, a large amount of purulent material was removed. At light microscopy, the tissue was demonstrated to be a pituitary abscess occurring in an otherwise normal pituitary gland. The high signal intensity on T1-weighted images does not correspond to the only MR description of a pituitary abscess given until now, reporting a mass isointense to white matter. These signal characteristics could emanate from the presence of small amounts of blood breakdown products in the proteinaceous content of the abscess. MR appearance of a pituitary abscess is possibly aspecific and could depend on the pathological composition of the lesion.

Pituitary Abscess Showing High Uptake of Thallium-201 on Single Photon Emission Computed Tomography. Case Report.

“…1,11,31) MR imaging with gadolinium shows pituitary abscess with thin and smooth rim enhancement. 9,10,15,17) Occasionally, MR imaging demonstrates surrounding brain damage with evidence of encephalitis and meningeal enhancement.…”

Pituitary Abscess with Panhypopituitarism Showing T1 Signal Hyperintensity of the Marginal Pituitary Area: A Non-invasive Differential Diagnosis of Pituitary Abscess and Pituitary Apoplexy

“…In this case, peripheral T1 signal hyperintensity and central T2 signal hyperintensity with ringed enhancement was demonstrated (Fig. 1) (5,6).…”

“…Meanwhile, T1 signal hyperintensity observed in the center of the abscess may correspond to a small amount of blood breakdown products in the proteinaceous purulent contents of the abscess (5). In this case, peripheral T1 signal hyperintensity and central T2 signal hyperintensity with ringed enhancement was demonstrated (Fig.…”

“…On the other hand, pituitary abscess presents a heterogeneous low density lesion on CT imaging, and disappearance of T1 hyperintensity of the pituitary posterior lobe (6,16,17) (24). Diabetes insipidus is also observed in about a half of the patients with pituitary abscess (5,(25)(26)(27) (28,29). In the future, successful treatment of pituitary abscess with conservative treatment may increase due to early diagnosis using our diagnostic approach (Table 5) …”

T1 Hyperintense Cystic Lesion – an Epidermoid or an Abscess?

“…Our case shows that an abscess situated in the same location can have identical signal characteristics. T1 hyperintensity in an abscess has been reported [10][11][12]. The capsule of a brain abscess may be hyperintense due to T1 shortening resulting from the presence of free radicals that accumulate as products of phagocytosis by macrophages [11].…”