Mucinous cystadenoma of the spleen Report of a rare case
Chao-Hung Hung, Chi-Sin Changchien, Shue-Shian Chiou,
and Chao-Cheng Hwang1
Division of Gastroenterology, Department of Medicine; 1Department of
Pathology, Chang Gung Memorial Hospital, Kaohsiung Medical Center,
Kaohsiung, Taiwan.
ABSTRACT
A rare case of mucinous cystadenoma of the spleen is reported. The patient
was a 63-year-old female with a cystic mass in the spleen demonstrated by echo
and CT scan. Surgical exploration revealed the tumor was confined in the spleen
with extravasation of mucinous material from a rupture into left subphrenic
space. Microscopically, the cystic space was lined by a single layer of
mucin-producing columnar epithelial cells without malignant change. We
reviewed the literature and found this may be the second case of splenic
mucinous cystadenoma.
Key words: mucinous cystadenoma, spleen INTRODUCTION
Mucinous cystadenomas are relatively uncommon benign cystic tumors. Most
of them are found in the ovary, pancreas, and appendix. However, they have also been
identified in other unusual sites such as retroperitoneum (1), fallopian tube (2), lung
(3), urinary bladder (4), liver (5) and spleen (6). In the English literature, there were
three cases of splenic mucinous cystadenocarcinoma reported previously (7,8,9), and
Miracco reported a case of splenic cyst lined with mucin-secreting epithelium (6).
Herein, we describe a mucinous cystadenoma of the spleen in a 63 year-old woman.
CASE REPORT
A 63 year-old Taiwanese woman had had a mass in her left abdomen for one
year. She had also suffered from cerebrovascular accident one year earlier. Otherwise,
her past history was unremarkable.
Physical examination revealed a palpable mass about two finger-breadths
below her left costal margin. Laboratory data was unremarkable. Abdominal plain
film showed a faint mass shadow in left upper abdomen, about 7 cm in diameter.
Abdominal ultrasonography revealed a cystic lesion in the spleen with multiple
internal septa, some of which had strong echogenicity (Figure 1). Computerized
tomography showed an 8 cm low-density cyst with internal septa and peripheral
calcification in the spleen (Figure 2).
On surgical exploration, splenectomy was done. A multiloculated cystic mass
was confined in the spleen and had a rupture on its upper pole, from which mucinous
material came out and into the left subphrenic space. There was no any
communication between the spleen and the pancreas. Grossly, the tumor was
measured about 9×6×4.5 cm in diameter. The cut surface showed multiloculated
cystic mass with smooth inner surface and profuse insipissated mucus.
Microscopically, papillary structure was found on the inner surface of cystic space ,
which was lined by a single layer of mucin-producing columnar epithelial cells
without malignant change (Figure 3). The splenic tissue was outside the cystic wall.
No pancreatic tissue was found in the specimen. So, mucinous cystadenoma of the
spleen was diagnosed although calcification was even found.
The postoperative course was uneventful. She was discharged one week later,
and abdominal ultrasonography demonstrated no recurrence one year later.
DISCUSSION
Splenic tumors are uncommon neoplasms. In 1985, Morgenstern et al. (10)
classified splenic tumors roughly into four categories: lymphoid, non-lymphoid
tumors, metastatic tumors, and tumor-like lesions, such as cysts and hamartomas. The
most common non-lymphoid tumors are vascular tumors. However, primary splenic
tumors from epithelial origin appear to be extremely rare.
From a few of case reports, splenic mucinous cystic tumors were defined as
cystic spaces lined by mucin-producing columnar cells and ranged from benign
cystadenoma to frankly malignant cystadenocarcinoma. To our knowledge, there were
three cases of mucinous cystadenocarcinoma in the spleen reported previously. Two
of them revealed a mucinous tumor arising in an aberrant intrasplenic pancreas (7,8).
The third case of mucinous cystadenocarcinoma in the spleen arose from undefined
origin (9). The author postulated that the splenic lesion was a delayed metastatic
recurrence of appendiceal carcinoma, either from a developmental misplacement of
endodermal epithelial tissue such as a heterotopic pancreas, or from mesothelium of
the splenic capsule. On the other hand, there was a case of splenic mucinous
cystadenoma according to the description of Miracco (6). So, our case may be the
second case of splenic mucinous cystadenoma.
Clinical presentation of patients with mucinous cystic tumors depends on the
site of the tumor and usually reveals nonspecific findings. In the image diagnosis,
sonography and CT scan may demonstrate a cystic lesion containing internal septum
or not. Peripheral calcification in the tumor may be seen more frequently in
cystadenocarcinoma than in cystadenoma (11), but the rule is not applied to our case.
Anyway, surgical intervention is needed for their definite diagnosis.
The exact histogenetic mechanism of splenic mucinous cystic tumors is
unknown except those arise from heterotopic pancreatic tissues (7,8). Elit et al.
reported a squamous cell carcinoma in an epidermoid cyst of the spleen (12) and
Ough et al. reported a case of mesothelial cyst of the spleen with squamous
metaplasia (13). Epidermoid cysts of the spleen are postulated that epithelial lining
cells of the cysts may originate in an invagination of the splenic capsular mesothelium
that undergoes metaplastic changes (13). Invagination of the capsular mesothelium
may be congenital or traumatic. Our case is a mucinous cystadenoma of the spleen
with a rupture on its upper pole which caused focal “pseudomyxoma peritonei” in the
left subphrenic space. There are no definite heterotopic pancreatic tissues in and
around the splenic lesion. So, we don’t know what is the exact histogenetic
mechanism. By way of Morinaga’s presentation (9), we postulate that the splenic
tumor may originate in the invagination of the splenic capsular mesothelium.
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FIGURE LEGENDS
Fig.1. Abdominal echo shows a cystic lesion in spleen (large arrowhead) with
multiple internal septa. Some of the septa have strong echogenicity
(arrowheads). SP: spleen
Fig.2. A series of abdominal CT of the patient shows an 8-cm low density mass
(small arrowhead) with peripheral calcifications (large arrowhead) and internal
septa in the spleen. SP: spleen; L: liver; G: gallbladder; RK: right kidney;
LK: left kidney; P: pancreas
Fig.3. Right: Cystic structure is found in the splenic tissue. (H & E stain 40x)
Left: The lining epithelium of the cyst is columnar epithelial cells with
prominent goblet cells (arrowheads) in papillary projection configuration
(H & E stain 100x)
