Chih-chun Wu, MD

Case History: A 55-year-old female presented with a one-month history of excessive thirst and polyuria. She had received an operation for adenocarcinoma of the lung about 21 months ago, with the final pathological staging being T2N0M0.

Findings: Her cranial MRI for newly developed symptoms disclosed a 1.2 x 1.2 x 2.2 cm sellar and suprasellar mass which extended and involved infundibulum. The tumor was isointense on both T1-weighted (T1WI) and T2-weighted (T2WI) images with small foci of hyperintensities.

After Gd-DTPA administration, contrast MRI revealed well but slightly heterogenous enhancement and findings in the rest of the brain were unremarkable. Adjacent clivus, cavernous sinus, and optic chiasm were intact.

Diagnosis: Metastatic adenocarcinoma of pituitary gland.

Discussion: Metastases to the sellar region account for approximately 1 percent of sellar masses on which a biopsy was performed, and by far most commonly arise from breast and lung adenocarcinomas. Pituitary metastases were reported to occur in 3 percent to 23 percent  of cancer patients in an autopsy series. Solitary pituitary metastasis is uncommon and was reported to occur in about 3.1 percent sellar and juxtasellar abnormalities by MRI.

Apparent symptoms from metastasis to pituitary gland are uncommon because widespread metastatic disease or overwhelming systemic complications of original malignancy might mask symptoms of hypopituitarism. The most common presenting symptoms: diabetes insipidus, anterior hypopituitarism, headache, visual defects, and ophthalmoplegia. The prognosis of patients with pituitary metastasis is poor, and the mean survival length is six to seven months in previous clinical series. It is not because of the location per se but because of the extent of systemic disease.

Differential diagnosis: There are more than 15 diseases for a sellar/suprasellar mass. The most common five account for more than 75 percent of all suprasellar masses in adults, and most other lesions stand for less than 1 percent to 2 percent each, including pituitary adenoma which is the most common one, meningioma, craniopharyngiomas, hypothalamic/chiasmatic glioma, and aneurysm.

Diagnostic clues: Imaging findings prefer the diagnosis of metastasis for a sellar/suprasellar mass:
Loss of posterior bright spot of normal pituitary gland
Infiltration of stalk causing thick stalk
Isointensity on both T1- and T2-weighted MR images 
Respect the diaphragm” early in the disease: Metastatic tumor usually had rapid growing and does not have enough time length to expand the diaphragm sellae, as contrast to the enlarged diaphragm in pituitary adenoma 
Invasion of juxtasellar structures such as cavernous sinus, sphenoid sinus or clivus 
Usually suprasellar or combined intrasellar and suprasellar in position: probably due to lack of blood-brain-barrier in these suprasellar structures.


References:
(1) Johnsen DE, Woodruff WW, Allen IS, et al. MR imaging of the sellar and juxtasellar regions. Radiographics 1991;11(5): 727-58
(2) Evanson J. Imaging the pituitary gland. Imaging 2002;14(2):93-102 
(3) Morita A, Meyer FB, Laws ER Jr. Symptomatic pituitary metastases. J Neurosurg 1998;89(1): 69-73

Chih-Chun Wu, MD, radiologist in Medical Imaging Department, Cheng Hsin General Hospital, Taipei, Taiwan

Articles

A 55-year-old female presented with a one-month history of excessive thirst and polyuria. She had an operation for adenocarcinoma of the lung about 21 months ago.

Metastatic Adenocarcinoma of Pituitary Gland

Clinical history: A 55-year-old female found to have a cardiac mass during evaluation of dizziness.

Figure 4: Oblique gradient-echo cine image

Findings: Her cardiac CT showed one space-taking lesion of soft tissue density confined in right atrium, without extension into adjacent organ. Cardiac MRI showed one well-defined intra-cardiac mass in right atrium attaching to myocardium. The tumor showed intermediate to bright on T1- and T2-weighted images and enhancement after Gd-DTPA administration.

Discussion: The most frequent mass within a cardiac chamber is thrombus. The overall frequency of cardiac tumor is 0.15 percent in echocardiographic series. Of all cardiac tumors, primary tumors are rare, while secondary tumors are about 40 times more frequent than primary cardiac tumors.

Cardiac hemangiomas are composed of endothelial cells that line interconnecting vascular channels. They are usually asymptomatic when diagnosed after infancy, and the commonest presentation is dyspnea on exertion if symptomatic.

Imaging findings: Cardiac hemangiomas may involve the endocardium, myocardium, or epicardium. They can arise from all chambers and also pericardium. On T1-weighted images, hemangiomas are intermediate to hyperintense. On T2-weighted images, they are hyperintense to myocardium. After Gd-DTPA administration, they usually have rapid enhancement during first-pass Gd contrast infusion because of their high vascularity, and usually show intense but inhomogeneous enhancement

Differential diagnosis: There are some methods to differentiate between thrombus and tumor on medical images. A thrombus shows low signal intensity on gradient-echo images, while tumors are hyperintense to myocardium. However, exceptions to this generalization are fresh blood clot can have high signal intensity, and some myxomas containing iron produce low signal and mimic thrombus. Besides, thrombus does not enhance after the administration of Gd-DTPA, whereas tumors show enhancement.

About 80 percent of primary cardiac tumors are benign, including myxoma, lipoma, papillary fibroelastoma, rhabdomyoma, and hemangioma. Cardiac pheochromocytoma is also reported and is very rare. Myxoma is the most common benign cardiac tumor. Myxoma is dumbbell shape, and is usually mobile with its shape varied during cardiac cycle.

One-fourth of primary cardiac tumors are malignant, with sarcomas being the most common, followed by primary cardiac lymphomas. There are features indicating malignancy of a primary cardiac tumor on medical images, including involvement of more than 1 cardiac chamber, wide point of attachment to the wall, necrosis within the tumor, extension outside the heart, and hemorrhagic pericardial effusion. Other signs of malignancy include intramural and intracavitary location, extension into the mediastinum, and rapid growth.

Conclusion: Cardiac hemangioma is a rare benign tumor of the heart. The differentiation of this benign tumor from the malignant types is essential in planning subsequent management. Cardiac MRI is a valuable tool to differentiate this tumor from other benign and malignant tumors.

References: 
1. Sutsch G, et al: echocardiographies. Schweiz Med Wochenschr 1991;121:621-62
2. Markel ML, Waller BF, Armstrong WF. Cardiac myxoma: a review. Medicine (Baltimore) 1987;66:114-25.
3. Oshima H. et al: J Thorac Imaging 2003;18:204-6.
4. Stephane Moniotte, et al: Cardiac hemangioma. Circulation 2005, 112:e103-e104
5. Ahmed Alsaileek, et al: Diagnostic features of cardiac hemangioma on cardiovascular magnetic resonance, a case report. The International Journal of Cardiovascular Imaging 2006: 699-702.
 

A 55-year-old female found to have a cardiac mass during evaluation of dizziness. Cardiac CT showed lesion of soft tissue density confined in right atrium.

Cardiac Hemangioma

Clinical history: A 49-year-old male suffered from mild right hand numbness for several months.

Findings: The cervical MRI showed one well-defined lesion lobular lesion in right side posterior epidural space of C5-6. It was homogenously marked hyperintense on T2-weighted image (T2-WI) and fat-suppression T2WI, hypointense on T1-weighted image (T1-WI), and marginal enhancement post Gadolinium administration.

Diagnosis: An epidural hemangioma (proven by operation and pathology).

Discussion: Cavernous hemangiomas are vascular malformations that constitute 5 percent to 12 percent of spinal vascular lesions. In the spine, hemangiomas located in the epidural space are rare, and most are cavernous. They constitute approximately 4 percent of all epidural tumors and 12 percent of all intraspinal hemangiomas.

Clinically, due to the slow growth of this lesion, the most common symptoms are chronic pain, myelopathy, and radiculopathy. But acute onset sensory deficit cause by hemorrhage was also been reported.

MR findings: The most common MR features solid hypervascular masses with lobular contour. A rim of low T2 signal intensity is relatively common; high signal intensity on T2-WI (cystic like).
J.W. Lee, et. al., categorized the MR imaging patterns of spinal hemangiomas into four types: type A for a cyst like mass with T1 hyperintensity, type B for a cyst like mass with T1 isointensity, type C for a solid hypervascular mass, and type D for an epidural hematoma. The anterior epidural space of the lumbar spine was a common location of types A and B, whereas the posterior epidural space of the thoracic or cervical spine were common in types C and D. Types A and B showed almost single-segment spinal involvement, while all cases from types C and D showed multisegmental spinal involvement.

Differential diagnosis: herniated disks, synovial cysts, granulomatous infections, neurogenic tumors, lymphomas, meningiomas, angiolipoma, pure epidural hematoma, and epidural extramedullary hematopoiesis depending on the MR types.

Diagnostic clues: Herniated disks or granulomatous infections frequently have a thick and irregular rim, while hemangioma usually has a smooth and relatively thin rim. A rim of low signal intensity may also favor an epidural hemangioma to a neurogenic tumor. Neural foraminal widening was reported to in cases of hemangiomas, and was probably a less helpful feature in the differential diagnosis with neurogenic tumors. Spinal angiolipoma is a rare form of epidural tumor showed T1 hyperintensity while solid type hemagnioma usually does not. Lymphomas or meningiomas frequently show isointense signal intensity on T2-WI, while spinal epidural hemangiomas usually reveal high signal intensity on T2-WI.

References: 
1. J.W. Lee, E.Y. Choc, S.H. Honge, H.W. Chung et al, Spinal Epidural Hemangiomas: Various Types of MR Imaging Features with Histopathologic Correlation, AJNR Am. J. Neuroradiol., 2007; 28:1242-8.
2. D.B. Orbach and J.B. Mulliken, Spinal Epidural Hemangiomas: Various Types of MR Imaging Features With Histopathologic Correlation, AJNR Am. J. Neuroradiol., 2008; 29(5): e31 - e31.
3. Jo BJ, Lee SH, Chung SE, Paeng SS, Kim HS, Yoon SW, et al.Pure Epidural Cavernous Hemangioma of the Cervical Spine that Presented with an Acute Sensory Deficit Caused by Hemorrhage, Yonsei Med J. 2006; 47(6): 877–80.

A 49-year-old male suffered from mild right hand numbness for several months. The cervical MRI showed one well-defined lesion lobular lesion in right side posterior epidural space of C5-6.