Case Report Rare Cystic Mucinous Cystadenoma Presenting as a Scrotal Mass Thomas T. Hoang, Suimin Qiu, and Gabriel Rodriguez Recently, our institution reported on a rare primary retroperitoneal mucinous cystadenocarcinoma which was only the second type of this kind of tumor ever reported in a male patient. To our knowledge, we report the first male case of a primary mucinous cystadenoma presenting as an enlarging scrotal mass. These lesions are extremely rare and represent only 0.3% of all appendiceal specimens. Because the number of these tumors remains limited, proven treatment regimens and the necessary follow-up have yet to be elucidated. We hope to provide further insight in the monitoring and treatment of these tumors. UROLOGY 70: 1223.e3–1223.e5, 2007. © 2007 Elsevier Inc.
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mucocele is an extremely rare entity derived from the appendix. The incidence ranges between 0.2% and 0.3% of all appendiceal specimens. Characterized by a cystic dilation of the lumen that fills with large amounts of mucus, mucoceles are predominantly caused by mucinous cystadenomas or mucinous cystadenocarcinomas. It has been assumed that these changes are caused by proximal obstruction of the lumen. Cheng’s experimental model showed that if the lumen of a rabbit appendix is surgically occluded, dilatation of the distal portion with flattening of the epithelium and accumulation of mucus results. Mucinous cystadenomas are generally benign but can grow to enormous proportions, causing pain and compressive effects on other abdominal structures or, rarely, as in our case, extending into the scrotum. We describe a unique case of the first ever reported mucinous cystadenoma discovered in a gentleman who presented with an enlarging scrotal mass.
CASE REPORT Our patient is a 70-year-old Hispanic man who had a medical history of a left renal cell carcinoma (RCC), pT1aN0M0, which was removed 5 years previous via an open radical nephrectomy in January 2001. The patient was observed by our division of urology for 5 years postoperatively and had no evidence of recurrent disease, confirmed by computed tomography (CT) scans, chest x-rays, lab work, and physical exams. During his initial workup in 2001, a 14-cm appendiceal mucocele was noted. Five years subsequently, his primary care physician evaluated him for sudden right testicular tenderness and scrotal swelling along with right lower extremity paresthesia. He also reported lethargy, shortness of breath, and From the Department of Surgery, Division of Urology, and Department of Pathology, University of Texas Medical Branch, Galveston, Texas Reprint requests: Gabriel Rodriguez, M.D., Department of Surgery, Division of Urology, Route 0540, University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555. E-mail:
[email protected] Submitted: February 2, 2007, accepted (with revisions): September 19, 2007
© 2007 Elsevier Inc. All Rights Reserved
Figure 1. (A, B) Computed tomography scan of the abdomen showing a 26 ⫻ 21 ⫻ 16-cm complex, septated, cystic mass within the retroperitoneum and several cysts within both kidneys. The mass was displacing the abdominal contents to the left and causing moderate right hydronephrosis. Hounsfield units measured to be 11, consistent with a cystic structure.
anorexia despite overall weight gain and increasing abdominal girth. He was referred to our division for urgent evaluation of an enlarging scrotal mass. On physical 0090-4295/07/$32.00 1223.e3 doi:10.1016/j.urology.2007.09.038
Figure 2. Gross (A) and microscopic features (B, C) of the lesion. (A) Large, multicystic lesion with relatively smooth cystic lining attached to the distal portion of the appendix (“A”) with soft tissue adhesions to the proximal portion of the spermatic cord (“S”). No gross abnormality was seen in testicular parenchyma (cut surface, “T”). (B) Cystic lining with single layer of mucinous epithelium with all nuclei located at the base of the cells. (C) Mucinous epithelium at higher magnification showing extracellular mucinous secretion and presence of intracellular mucin component.
examination, we easily identified a large nontender right upper and lower quadrant abdominal mass on inspection and palpation. The scrotal exam revealed a large, firm mass that did not transilluminate. A CT scan of the abdomen and pelvis revealed no evidence of RCC recurrence but an interval development of a massively large, fluid-filled right-sided abdominal mass extending all the way into the scrotum (Fig. 1A, B). The radiologist interpretation was a “coelomic cyst.” Owing to an increase in the abdominal symptoms, the patient underwent an exploratory laparotomy via a large midline incision, with the most unusual intraoperative findings. The large mass was identified and was arising directly from the appendix. The massive lesion was densely adherent to surrounding intra-abdominal organs, right hemidiaphragm, and liver. This mass extended all the way into the scrotum. The mass was carefully dissected in its entirety along with the appendix, right spermatic cord, and testicle. Great care was taken not to puncture or rupture the massive cystic structure. The pathology specimen revealed a mucinousfilled mass grossly 3 kg and 27 ⫻ 15 ⫻ 10 cm in dimensions (Fig. 2A–C). A mucinous cystadenoma arising from the distal tip of the appendix was the final pathology. Upon follow-up 7 months after the surgery, the patient had a CT scan (Fig. 3) showing dramatic resolution of the mass, and reported a dramatic improvement in his pain, discomfort, and weight.
DISCUSSION The English medical literature reports only 28 cases of retroperitoneal mucinous cystic masses, 26 of which are in women.1– 8 We report the 29th case. Our case is especially rare because it is only the third male patient 1223.e4
Figure 3. Follow-up computed tomography scan of the abdomen showing resolution of the mass 7 months after surgery.
with mucinous cystadenoma reported in the literature and the first and only to present with genitourinary complaints. Motoyama et al.9 reported the first male patient in 1994, with little mention of clinical data or follow-up. The second case came from our institution, describing an abnormally large retroperitoneal mucinous cystadenocarcinoma found during exploratory laparotomy for a supposed renal cystic lesion. In our initial case, we were unable to identify a pedicle or the primary organ of attachment, which is a common finding reported in the literature. Cases can become perplexing histologically because they contain areas that appear benign, borderline malignant, or frankly malignant.9 There are primarily four hypotheses for the origin of these rare tumors. The first explanation is that primary retroperUROLOGY 70 (6), 2007
itoneal mucinous cystoadenocarcinomas (PRMCs) arise from teratomatous lesions where the columnar epithelium becomes the predominant cell line.10 The second possibility is that they arise from ectopic ovarian tissue11; yet, no ovarian tissue has ever been found within a retroperitoneal mucinous cystadenocarcinoma.12 The third hypothesis is that the tumors are remnants of the embryonal urogenital apparatus, where the cysts develop from specialized mesothelial cells of the urogenital ridge.12 The final theory, and most widely accepted, is that PRMCs arise from invaginations of the peritoneal epithelium during embryonic growth and subsequently undergo metaplasia.13 The clinical course appears to be indolent. However, these tumors can become locally aggressive. Overall, the prognosis and tumor biology of these tumors is uncertain owing to their rarity and the short follow-up on the patients. The longest reported follow-up is 6 years.14 Mikami and associates3 believe that presence of a mural nodule within the cyst wall portends worse prognosis given that 3 of the 4 patients who died had a mural nodule. Although our recent case shares similar histological features with female patients with PRMC, given the paucity of cases, it is hard to determine whether these tumors have a similar clinical behavior and prognosis in men and women. The reason for this female predominance is unknown. Another apparent distinction between men and women is that the tumors develop earlier in women with a mean age of presentation of 42.4 years (range, 17– 86 years), whereas the two male patients presented at 63 and 83 years. Mucinous cystadenocarcinomas can also arise in the liver, pancreas, and ovary. In our present case, the patient had renal cysts and preoperative evaluation could not exclude benign renal cystic disease as the origin of the cystic retroperitoneal mass. Renal lymphangiomas can also present as slow-growing, flank or abdominal masses that have an indolent clinical course and imaging will reveal large perirenal and peripelvic cysts. These lesions can be confusing in that diagnosis is often made through surgical excision.15 The urologist should be aware and consider cystic mucinous tumors in the differential diagnoses of abdominal and scrotal masses. Differential diagnoses of scrotal masses include hydrocele, testicular cancer, inguinal hernia, varicocele, spermatic cord pathology, infection, and a benign cyst. A large cystic mass arising in the abdomen presenting in the scrotum is very rare and determining the etiology can be difficult. We present this case as the first ever described in the literature to date. These tumors
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typically present with mass effects, have an indolent course, and can become very large before they cause clinical problems. Early diagnosis can be challenging preoperatively, and in most cases exploratory laparotomy is the primary means of diagnosis and treatment. Mucinous cystadenomas and cystadenocarcinomas can display an aggressive clinical course. To date, the appropriate treatment regimen has yet to be discovered. Extirpative surgery appears to be the treatment of choice to obtain a definitive pathologic diagnosis and should be considered the standard of care.
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