AJR 2005; 184:1211-1215
© American Roentgen Ray Society
Cystic Lesions in the Posterosuperior Portion of the Humeral Head on MR Arthrography: Correlations with Gross and Histologic Findings in Cadavers
Wook Jin1,
Kyung Nam Ryu2,
Yong Koo Park3,
Weon Kyu Lee4,
Sung Hye Ko2 and
Dal Mo Yang1
1 Department of Diagnostic Radiology, Gil Medical Center, Gachon Medical School,
Inchoen 405-760, South Korea.
2 Department of Diagnostic Radiology, Kyung Hee University Medical Center, Kyung
Hee University, Hoekidong 1, Dongdaemoon-ku, Seoul 130-702, South Korea.
3 Department of Anatomic Pathology, Kyung Hee University Medical Center, Kyung
Hee University, Seoul 130-702, South Korea.
4 Department of Anatomy, Gachon Medical School, Inchoen 405-760, South
Korea.
Received April 22, 2004;
accepted after revision July 28, 2004.
Address correspondence to K. N. Ryu.
Abstract
OBJECTIVE. The purpose of this study was to describe the appearance
of cysts in the posterosuperior portion of the humeral head on MR arthrography
and to correlate the MRI findings with the gross and histologic findings in
cadavers.
CONCLUSION. Cysts in the posterosuperior portion of the humeral head
(the bare area) were located in the lateral humeral head just posterior to the
greater tuberosity. These cysts were lined with collagen connective tissue and
were connected to the joint spaces. We suggest that these pseudocysts in the
posterosuperior portion of the humeral head may be a normal variant rather
than being an abnormal change or vascular channel.
Introduction
During shoulder MRI for the evaluation of the glenoid labrum,
rotator cuff muscles, or contour of bone structure, we can often observe small
cystic changes in the posterosuperior portion of the humeral head.
Subchondral cysts occur in many articular diseases. For example,
osteoarthritis, rheumatoid arthritis, intraosseous ganglia, neoplastic
processes, posttraumatic processes, and calcium pyrophosphate deposition
disease all may cause subchondral cysts. In addition, the presence of a cystic
area within the humerus and near the rotator cuff insertion is regarded as
supportive evidence of a cuff disorder
[1]. However, cystic changes in
the humeral heads have also been reported in normal shoulders
[2-4].
To our knowledge, no histologically proven report has been issued about these
cystic changes of the humeral head in normal shoulders without a rotator cuff
disorder or articular disease.
The purpose of this study was to describe the appearance of cysts in the
posterosuperior portion of the humeral head on MR arthrography and to
correlate the MRI findings with the gross and histologic findings in
cadavers.
Materials and Methods
MR arthrography of the glenohumeral joint was performed in nine cadaveric
shoulders (five right shoulders and four left shoulders) derived from five
cadavers of subjects who were 37-88 years old at death (mean age, 60 years).
MRI was performed after the fluoroscopically guided intraarticular injection
of 15-20 mL of a solution of diluted gadopentetate dimeglumine (Magnevist,
Schering), which was made by mixing 1 mL of the contrast medium with 250 mL of
normal saline. The shoulder was placed in the supine position. MR images were
obtained by using a 1.5-T scanner (Magnetom Vision, Siemens) with a shoulder
coil. Axial and oblique coronal fat-suppressed T1-weighted spin-echo and
T2-weighted spin-echo images were obtained. The technical parameters were
TR/TE, 500/12 for the fat-suppressed T1-weighted spin-echo images and 3,500/98
for the T2-weighted spin-echo images, with a field of view of 12-16 cm, a
slice thickness of 5 mm, no interslice gap, and a matrix size of 192 x
256 or 256 x 256.
Subsequently, the nine shoulders were dissected under the supervision of
one experienced orthopedic surgeon, who used an anterior approach that was
designed to avoid damage to the posterior and lateral portions of the humeral
head. After detecting cortical dimples in posterosuperior portions of the
humeral heads that were suggestive of cystic lesions on MR images, we selected
five humeral heads with clearly visible cystic lesions in the humeral heads.
We divided the posterosuperior portion of the humeral head including cortical
dimples into five bone segments (an approximately 1-cm3 volume)
each. After fixing the bone segments, we divided each segment into
undecalcified bone sections (10-mm in thickness) with a soft-tissue cutting
machine to avoid damage to soft tissue in or near cysts. Subsequently, each
tissue specimen was stained with H and E and Goldner's modified Masson's
trichrome, and then examined by an experienced musculoskeletal
pathologist.
Results
Nine shoulders of five cadavers were included in this study, but one right
shoulder was excluded because it showed severe degenerative osteoarthritis and
rotator cuff tear on gross inspection and on MR arthrographic images.
Accordingly, four right and four left shoulders were included in this study.
In these eight shoulders, there was no evidence of significant degenerative
change or rotator cuff tear on MR images.
MRI Findings
Between one and three cystic lesions (mean, 2.3) were observed in each
humeral head, and the longest of these cystic lesions was about 2-4 mm (mean,
2.56 mm). All lesions were observed as round or oval high-signal-intensity
lesions on T2-weighted and fat-suppressed T1-weighted MR arthrography images.
Also, shoulder joint spaces were filled with contrast medium of high signal
intensity on fat-suppressed T1-weighted images, which established the presence
of connections between joint spaces and cystic lesions of the humeral heads.
All of these cystic lesions were located in lateral humeral heads just
posterior to the greater tuberosity (Figs.
1A and
1B).
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Fig. 1A. —Pseudocyst of humeral head in cadaver of 61-year-old man.
T2-weighted axial (A) and coronal (B) images show
well-circumscribed high signal intensity (arrow) in posterosuperior
portion of humeral head. There was no evidence of degenerative change or
rotator cuff tear (not shown).
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Fig. 1B. —Pseudocyst of humeral head in cadaver of 61-year-old man.
T2-weighted axial (A) and coronal (B) images show
well-circumscribed high signal intensity (arrow) in posterosuperior
portion of humeral head. There was no evidence of degenerative change or
rotator cuff tear (not shown).
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In the humeral heads, there was no significant evidence of degenerative
changes such as cortical thinning, cartilage thinning or breakage, subchondral
cyst formation, or subchondral bone marrow change on MR images.
Gross Findings
After dissecting the shoulders and opening the joint capsules, we found
small variably sized focal depressions or dimples with round or oval contours
in the posterosuperior portion of the humeral head—the presumed area of
cystic lesion on MRI. These lesions had openings into joint spaces and were
located in the junctions between the humeral heads and the joint capsule
attachments, just posterior to the greater tuberosity. However, the surfaces
of the nearby cartilage in the humeral heads were relatively well preserved
without defect or color change.
Histologic Findings
During histologic examination of five specimens (Figs.
1C and
2), cystic lesions in the
posterolateral portions of humeral heads were found to have connections with
the joint spaces and focal discontinuities of cortical bones with pseudocyst
formations, which had no synovial lining. All cystic lesions were located in
the bare areas of the humeral heads without cartilage coverage. These cystic
lesions had walls of relatively thick collagen fibroconnective tissues and no
inner myxoid content or mucoid material. The inner walls of most lesions
showed no specific cells, except for some cuboidal cells, and there was no
evidence of vascular endothelial cells, macrophages, osteoclasts, or marks due
to hemorrhage. Adjacent to the openings of pseudocysts, no degenerative
changes such as thinning, cracking, or breakage in neighboring cartilage were
observed. The inner trabeculae and the bone marrow also showed normal findings
near pseudocysts.
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Fig. 1C. —Pseudocyst of humeral head in cadaver of 61-year-old man.
Photomicrograph of pseudocyst in undecalcified bone section shows dense
collagenous wall without definite epithelial lining cells. Cortical defect
(arrow) connects with joint space. No hemorrhage or hemosiderin-laden
macrophages are evident. (H and E; original magnification, x12.5)
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Fig. 2. —Photomicrograph of pseudocyst in undecalcified bone section
of humeral head in cadaver of 60-year-old man. Lobulated cystic structure is
shown. Articular cartilage (C) adjacent to pseudocyst has normal appearance
and smoothly fades out at opening of pseudocyst and trabecular bone
surrounding pseudocyst. Adjacent cortex and surrounding trabeculae of
pseudocyst show normal appearance without degenerative change or other
abnormalities. (H and E; original magnification, x12.5)
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MRI-Histologic Findings Correlation
Small cystic lesions filled with contrast medium in the posterosuperior
portions of the humeral heads on the MR arthrographic images corresponded to
pseudocyst formations beneath the cortical bones histologically. These lesions
became connected to the joint spaces, as determined by histologic examination,
just as the contrast medium filled the cystic lesions from the joint spaces as
seen on the MR arthrographic, images. The lesions were not lined with synovium
but rather with collagen fibroconnective tissues. The lesions had focal
cortical defects as their openings, and no degenerative changes were evident
in nearby cortex or cartilage. Overall, the cystic lesions in the
posterosuperior portions of the humeral heads in this study were not
subchondral cysts from degenerative changes, vascular structure, or synovial
cysts.
Discussion
In humeral heads, cystic changes occur because of articular diseases and
tumorous conditions. However, the cystic changes often identified are located
in the epiphysis or metaphysis near the joint spaces, and these commonly
result from articular diseases. In particular, subchondral cysts are common in
many types of osteoarticular diseases. Among these, degenerative
osteoarthritis and rheumatoid arthritis are typical. In addition,
osteonecrosis, calcium pyrophosphate deposition disease, hemophilic arthritis,
trauma, and intraosseous ganglia all may cause subchondral cysts
[5].
Subchondral cysts appear between thickened subchondral trabeculae. Cysts
often are multiple and histologically can contain myxoid and adipose tissue,
occasional cartilage with surrounding fibrous components, and peripheral
sclerotic bone [6]. Resnick et
al. [7] applied the term
"geodes" to subchondral cysts from osteoarthritis, rheumatoid
arthritis, calcium pyrophosphate deposition disease, and osteonecrosis. In
degenerative osteoarthritis, proposed theories of the pathogenesis of cyst
formation include the bone contusion theory and the synovial fluid intrusion
theory. In rheumatoid arthritis, geodes result from inflammatory changes in
the synovial lining of the articular cavity creating pannus that extends
across the cartilaginous surface and eventually destroys cartilage and
bone.
Several studies reported that cystic changes of the greater tuberosity and
of the head of the humerus were observed in 50-80% of shoulders with rotator
cuff tears [3,
4,
8]. However, cystic changes are
also observed in normal shoulders
[2-4].
In our experience, small cystic changes are often detected in the humeral
heads of normal shoulders without rotator cuff tears.
On the basis of a report by Yoon et al.
[9], subchondral cysts in the
posterolateral portion of the humeral head were detected in approximately 72%
of cases. In addition, about 91% of cysts were connected to the joint cavity.
However, in the present study, cystic lesions in the humeral head were
presumed to be subchondral cysts without histologic confirmation. Moreover, no
detailed differential percentage of cystic change in the humeral head was
provided according to abnormal change in the shoulders, such as that due to a
rotator cuff tear.
A study was also made of 140 painful shoulders on MRI to determine the
relationship between cystic changes of the humeral head and the integrity of
the rotator cuff [4]. In that
study, cystic changes were observed in 49 (35%) of 140 shoulders, and the most
common site was the posterior half of the middle facet of the greater
tuberosity. The second most common site was the attachment of the
supraspinatus tendon. It was concluded that there are two distinct types of
cystic changes: one at the attachment of the supraspinatus and subscapularis,
which is closely related to tears of these tendons, and the other in the bare
area, which is related to a degenerative aging process from the lack of
cartilage coverage.
However, except cystic changes related to rotator cuff tear or degenerative
aging process, cystic changes in the humeral heads on MR images can be caused
by vascular channels [10]. In
this study, dorsolateral vascular channels were found within the bare area of
the proximal humerus, and these could be differentiated from cysts seen with
partial tears of the supraspinatus and infraspinatus tendons.
Cystic changes close to the bare area of the humerus are viewed as
consequences of a degenerative aging process
[4], and dorsolateral vascular
channels are reported [10]
resemble the cystic changes in the posterolateral portion of the humeral head
found in our study. However, in our study, these cystic changes showed no
inner vascular structure and no evidence of degenerative changes in nearby
cartilage or bone, such as thinning of cartilage, breakage of cartilage, or
trabecular change. Therefore, these cystic changes were not true cysts but
rather pseudocysts.
In summary, cystic lesions are commonly visible in the posterosuperior
portions of the humeral heads (the bare areas), just posterior to the greater
tuberosity on shoulder MR images. These were found to be focal dimples at
gross examination and pseudocysts lined with collagen fibroconnective tissues
at histologic examination. These cystic lesions were connected with the joint
spaces, and no degenerative change was evident in nearby osteochondral
structures. Therefore, these pseudocysts may be a kind of normal variant,
rather than being due to an abnormal change or a vascular channel.
References
- Zlatkin MB, Chao P. The shoulder. In: Mink JH, Deutsch AL, eds.
MRI of the musculoskeletal system. New York, NY:
Raven, 1990: 19-84
- Mirowitz SA. Normal rotator cuff: MR imaging with conventional and
fat-suppression techniques. Radiology1991; 180:735
-740[Abstract/Free Full Text]
- Needell SD, Zlatkin MB, Sher JS, Murphy BJ, Uribe JW. MR imaging of
the rotator cuff: peritendinous and bone abnormalities in an asymptomatic
population. AJR1996; 166:863
-867[Abstract/Free Full Text]
- Sano A, Itoi E, Konno N, Kido T, Urayama M, Sato K. Cystic changes
of the humeral head on MR imaging. Acta Orthop Scand1998; 69:397
-400[Medline]
- Kaplan PA, Dussault RG, Buchanan PK, Berardo PV, Gizienski TA,
Short JG. Musculoskeletal case of the day: congenital lipoatrophic diabetes.
AJR 1996;167:252
-259[Free Full Text]
- Milgram JW. Morphologic alterations of the subchondral bone in
advanced degenerative arthritis. Clin Orthop1983; 173:293
-312
- Resnick D, Niwayama G, Coutts RD. Subchondral cysts (geodes) in
arthritic disorders: pathologic and radiologic appearance of the hip joint.
AJR 1977;128:799
-806[Abstract]
- Kernwein GA. Roentgenographic diagnosis of shoulder dysfunction.
JAMA 1965;194:1081
-1085
- Yoon YC, Ryu KN, Yoon Y, Rhee YG. Subchondral cysts of the humeral
head: MR imaging findings [in Korean]. J Korean Radiol
Soc 1999;40:329
-332
- Anderson SE, Steinbach LS, Hertel R. Normal variant or degenerative
cyst? Recognizing dorsolateral vascular channels to the proximal humeral
epiphysis. 2000 RSNA. Oak Brook, IL: Radiological
Society of North America, 2000:529
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Abstract
Introduction
