AJR 2004; 182:144-146
© American Roentgen Ray Society
MRI Diagnosis of Subpubic Cartilaginous Cyst
Connie E. Kim1 and
H. Scott Beasley
1 Both authors: Department of Radiology, Western Pennsylvania Hospital, 4800
Friendship Ave., Pittsburgh, PA 15224.
Received May 5, 2003;
accepted after revision June 26, 2003.
Address correspondence to C. E. Kim.
Introduction
In 1996, Alguacil-Garcia and Littman
[1] described in the pathology
literature two cases of unusual subpubic cystic masses. Both patients were
multiparous postmenopausal women who presented with vulvar masses. The lesions
were associated with the pubic bone; had defined collagenous capsules; and
contained gelatinous degenerating fibrocartilaginous tissue, acellular debris,
and mucin. The diagnosis for both lesions was subpubic cartilaginous cyst. We
found no other reported cases nor any description of the imaging appearance of
this lesion in the literature. In this report, we describe the MRI appearance
of such a lesion in a 70-year-old woman.
Case Report
A 70-year-old gravida 3, para 3 woman presented to her gynecologist with a
vulvar mass. Physical examination revealed a hard 4 x 4 cm mass that was
subpubic, supraurethral, and fixed at the midline. The lesion was not painful,
and the patient had no history of dysuria, vaginal bleeding, or other related
symptoms. MRI of the pelvis revealed a 3-cm mass immediately caudad to the
symphysis pubis that had a broad margin of contact with the adjacent
symphysis. The lesion was hypointense relative to muscle on T1-weighted
sequences (Fig. 1A) and
heterogeneously hyperintense on T2-weighted sequences (Figs.
1B and
1C). After administration of IV
gadolinium chelate, a thin enhancing wall with no internal enhancement was
seen (Fig. 1D). No signal
abnormality was seen in the adjacent pubic bone marrow or the adjacent
tissues. The clitoris was displaced but not invaded and was clearly separate
from the lesion.
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Fig. 1D. —70-year-old woman with vulvar mass. Gadolinium-enhanced
T1-weighted spoiled gradient-echo image obtained with fat suppression shows
enhancement of wall of cystic lesion (arrow). No internal enhancement
is seen.
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The mass was resected and at gross pathologic examination was found to be a
cystic yellowish tan nodule. Microscopic examination revealed benign
cartilaginous tissue with reactive changes at the periphery
(Fig. 1E) and central cystic
degeneration with amorphous material (Fig.
1F). Surgery confirmed that there was no involvement of the
surrounding tissues.
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Fig. 1E. —70-year-old woman with vulvar mass. Photomicrographs of
histopathologic specimen shows benign cartilaginous tissue with reactive
changes at periphery (E) and central cystic degeneration with amorphous
material (F). (H and E, x100 for E and
x25 for F)
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Fig. 1F. —70-year-old woman with vulvar mass. Photomicrographs of
histopathologic specimen shows benign cartilaginous tissue with reactive
changes at periphery (E) and central cystic degeneration with amorphous
material (F). (H and E, x100 for E and
x25 for F)
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Discussion
The pubic symphysis is a nonsynovial amphiarthrodial joint that is situated
at the confluence of the two pubic bones. The joint is composed of a thick
fibrocartilaginous disk sandwiched between thin layers of hyaline cartilage.
Pathologic processes that affect the pubic symphysis may be infectious,
congenital, metabolic, inflammatory, traumatic, or degenerative
[2]. Few cystic processes have
been described.
Large cysts associated with the pubic symphysis have rarely been reported.
Morita et al. [3] reported the
case of a woman with known rheumatoid arthritis who developed large
pseudosynovial cysts associated with the pubic symphysis, and Verrall et al.
[4] described subchondral cyst
formation in the pubic symphysis in Australian football players. Kier
[5] described the MRI
appearance of several types of nonovarian vulvar cysts: Naboth's cysts,
Bartholin's cysts, Gartner's cysts, and paratubal cysts. None of these lesions
is closely associated with the pubic symphysis, and all are generally
anatomically distinct from the subpubic cyst we described.
As discussed earlier, we know of only two cases of subpubic cartilaginous
cysts that have been reported in the literature
[1], and to our knowledge, the
MRI appearance of these cysts has not been previously described.
Alguacil-Garcia and Littman [1]
hypothesized that subpubic cartilaginous cysts may arise from degenerative
changes because both of their patients were multiparous women. Those
researchers also speculated that the cysts represent cystic, ganglionlike
mucinous degeneration of the arcuate ligament tissues with cartilaginous
metaplasia. In these two previously described patients, there was no evidence
of recurrence after the removal of the lesions.
Our case illustrates the usefulness of MRI for evaluating the female
pelvis. MRI showed that the cyst originated from the pubic symphysis. We
confirmed its cystic nature and excluded such diagnoses as urethral
diverticulum; Bartholin's cyst; or solid neoplasm arising from the clitoris,
urethra, or perineum. The pathologic findings of the lesion were most
consistent with the findings described by Alguacil-Garcia and Littman
[1], and we have reported our
case to further document the existence of this lesion and to illustrate the
MRI characteristics of subpubic cartilaginous cysts.
Acknowledgments
We thank Manju E. Nath of the Department of Pathology, Western Pennsylvania
Hospital, for his contributions.
References
- Alguacil-Garcia A, Littman CD. Subpubic cartilaginous cyst: report
of two cases. Am J Surg Pathol1996; 20:975
–979[Medline]
- Gamble JG, Sheldon CS, Freedman M. The symphysis pubis: anatomic
and pathologic considerations. Clin Orthop1986; 203:261
–272
- Morita M, Yamada H, Terahata S, Tamai S, Shinmei M. Pseudo-synovial
cyst arising at the pubic bone region and forming a large
femoral–inguinal mass. J Rheumatol1997; 24:396
–399[Medline]
- Verrall GM, Slavotinek JP, Fon GT. Incidence of pubic bone marrow
oedema in Australian rules football players: relations to groin pain.
Br J Sports Med2001; 35:28
–33[Abstract/Free Full Text]
- Kier R. Nonovarian gynecologic cysts: MR imaging findings.
AJR 1992;158:1265
–1269[Free Full Text]
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Introduction
Case Report
