Thick Infundibular Stalk
Anne G. Osborn, MD, FACR
DIFFERENTIAL DIAGNOSIS
Common
Neurosarcoid
Germinoma
Less Common
Meningitis
Histiocytosis
Lymphocytic Hypophysitis
Rare but Important
Metastasis (to Stalk/Pituitary)
Ectopic Neurohypophysis
Pituicytoma
Lymphoma, Primary CNS
Leukemia
Transected Pituitary Stalk
ESSENTIAL INFORMATION
Key Differential Diagnosis Issues
Know what normal stalk looks like!
Tapers from top (at tuber cinereum) to bottom (pituitary gland)
2 mm or less in diameter
“Thick” stalk
More than 2 mm diameter
Loss of normal “top to bottom” tapering
Patient age extremely important in differential diagnosis of thick stalk
Child = histiocytosis, germinoma
Adult = neurosarcoidosis, hypophysitis, metastasis, lymphoma
Helpful Clues for Common Diagnoses
Neurosarcoid
Isolated stalk lesion uncommon
Adults > > children
Germinoma
May be primary in stalk/hypothalamus
Often presents with diabetes insipidus (DI)
Helpful Clues for Less Common Diagnoses
Meningitis
“Stalkitis” usually part of generalized pia-subarachnoid space infection
Isolated stalk infection rare
Histiocytosis
Calvarium > brain parenchyma, meninges
Infundibulum/hypothalamus = most common CNS site
Children > adults
Absent pituitary “bright spot” common
Stalk thick, hyperintense, enhancing
Lymphocytic Hypophysitis
Thick, enhancing stalk ± pituitary mass
Helpful Clues for Rare Diagnoses
Metastasis, Lymphoma
Look for other lesions, infiltration of adjacent structures
Pituicytoma
Posterior pituitary “bright spot” often absent
Other Essential Information
Pituitary stalk anomaly, transected stalk (traumatic/post-surgical) can make stalk appear “stubby”Related posts:
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