Imaging of mucocoele of the appendix with emphasis on the CT findings: a report of 10 cases

AIM: Mucocoele of the appendix denotes an obstructive dilatation of the appendiceal lumen due to abnormal accumulation of mucus. It is sometimes associated with pseudomyxoma peritonei, which predicts a malignant origin. We present the CT findings and additional imaging studies of 10 patients with neoplastic appendiceal mucocoele and discuss the clinical implications. MATERIALS AND METHODS: Abdominal CT findings from 10 patients with appendiceal mucocoele were reviewed. Barium enema, US and MRI were additionally performed in three patients. There were five men and five women aged 45-80 years. Special attention was directed to the shape and nature of the mass, its relation to the caecum and the presence of ascites or peritoneal implants, as well as possible additional ovarian tumours in female patients. RESULTS: The mucocoele was an incidental finding in five patients. They were either spherical or elongated cystic lesions, attached to the wall of the caecum, six of them with mural calcification. Ascites were present in six patients and hypodense large peritoneal implants representing pseudomyxoma peritonei in four. Pathologically the series included five cases of cystadenoma (in one, a malignant pseudomyxoma peritonei subsequently developed), four cases of cystadenocarcinoma and one villous adenoma (this patient later developed pseudomyxoma peritonei). Pseudomyxoma peritonei was found in five cases. Three women had associated ovarian cystic tumour. CONCLUSION: The appearance of an appendiceal mucocoele is quite characteristic and can be diagnosed on CT. CT can also depict additional findings suggesting pseudomyxoma peritonei. In women with an appendiceal mucocoele the ovaries should be examined closely for cystic tumour and vice versa.     

CT in pseudomyxoma peritonei: a review of 17 cases

AIM: To describe the computed tomography (CT) findings in pseudomyxoma peritonei. MATERIALS AND METHOD: Two observers independently and retrospectively reviewed the CT images of 17 consecutive patients (nine women, eight men, mean age 53 years) with histologically proven pseudomyxoma peritonei. RESULTS: Six patients had small volume disease where pseudomyxoma peritonei was present in focal collections in the peritoneal cavity. Eleven had large volume disease that completely, or almost completely, filled the peritoneal cavity. Pseudomyxoma peritonei is characterized by low attenuation mucinous ascites on CT. Areas of high attenuation, septae and calcification are seen more commonly within it as the volume of disease increases. The pattern of accumulation of pseudomyxoma peritonei follows the normal flow of peritoneal fluid. It initially seeds at sites of relative stasis and as large volume disease develops it fills the remaining spaces in the peritoneal cavity and pressure effects dominate imaging. Pseudomyxoma peritonei may extend into hernial orifices or the pleural cavity. CONCLUSION: Pseudomyxoma peritonei is difficult to diagnose clinically. However, the pattern of accumulation of disease is predictable and can be recognized on CT.     

腹膜假性黏液瘤的CT诊断

目的:认识和提高腹膜假性黏液瘤的CT表现及诊断.方法:回顾性分析16例经病理或细胞学检查证实的腹膜假性黏液瘤的CT和临床表现.结果:腹膜假性黏液瘤是以黏液性腹水为特征,临床主要表现为腹胀、腹块等.依据CT表现不同可分为弥漫性和局限性两种类型,主要CT表现包括腹水内密度不均匀8例,肝脾表面黏液样结节10例,多发分隔的囊性病变5例和网膜增厚或"网膜饼"征6例.结论:典型的CT表现可以诊断腹膜假性黏液瘤,CT检查可为临床治疗的选择和改善预后提供有价值的信息.     

Radiologic findings of urachal mucinous cystadenocarcinoma causing pseudomyxoma peritonei

Urachal mucinous cystadenocarcinoma causing pseudomyxoma peritonei is very rare. We report a case of a 59-year-old man with urachal mucinous adenocarcinoma associated with pseudomyxoma peritonei, and our radiologic findings. Ultrasonography revealed a well delineated, large cystic tumor adjacent to the anterior wall of the abdomen. Computed tomography and magnetic resonance imaging revealed a tumor of which the left posterior wall was defective. A large amount of ascites was present in the peritoneal cavity. The ascites caused displacement of the intestinal structures toward the dorsal region. The tumor wall and septa in the ascites were well enhanced on contrast-enhanced images. Radiologically, pseudomyxoma peritonei due to rupture of urachal cystic tumor was considered. The pathologic diagnosis was mucinous adenocarcinoma and pseudomyxoma peritonei.     

腹膜假性黏液瘤CT诊断(附21例报告)

目的:探讨腹膜假性黏液瘤的CT表现,提高对本病的认识.方法:搜集经手术、病理证实的腹膜假性黏液瘤21例,回顾性分析其CT表现.结果:21例中原发瘤恶性8例,其中卵巢黏液囊腺癌3例,阑尾黏液囊腺癌4例,结肠黏液腺癌1例;良性13例,其中阑尾黏液囊腺瘤4例,阑尾黏液囊肿2例,卵巢黏液囊腺瘤6例,胰腺黏液囊腺瘤1例.CT平扫见肝脾等实质脏器边缘扇贝样或结节状压迹,腹腔不规则囊实性肿块,CT值19.9～25.8 HU;脏器周围、网膜间隙、腹腔、盆腔见大量黏液性腹水,CT值10～15 HU;腹膜增厚,厚度1.0～2.0 cm;增强扫描显示囊实性病变仅见囊壁、网膜、腹膜轻度强化,囊内病灶无明显强化.结论:腹膜假性黏液瘤CT表现具有一定的特征,是诊断腹膜假性黏液瘤的重要方法.     

腹膜假粘液瘤的CT表现与病理基础

目的:探讨腹膜假粘液瘤的CT表现及其病理基础。方法:回顾性分析6例经手术病理证实的腹膜假粘液瘤的CT表现,并与手术病理对照分析。结果:6例患者均为腹腔内弥漫性病变,CT表现为粘液样腹水伴有分隔,囊性包块,肝脾表面扇形压迹,肠管受压移位,腹膜外囊性包块。显微镜下可见大粘液池伴血管充血和慢性炎性细胞浸润,粘液中有腺上皮细胞。结论:CT能反映腹膜假粘液瘤的病理学特征。     

Appendiceal mucocele with pseudomyxoma peritonei mimicking ovarian tumor with peritoneal carcinomatosis

Appendiceal mucocele with unprompted pseudomyxoma peritonei is a rare malignant tumor, which is difficult to diagnose before surgery. We present a case of a 62-year-old woman, and subsequently discuss the clinical and imaging presentation of mucoceles. Findings on CT scan suggested 2 diagnoses: appendiceal mucocele with pseudomyxoma peritonei and malignant ovarian tumor with peritoneal carcinosis. MRI suggested the former diagnosis, showing a large tubular mass at the base of appendix with discontinuous wall, and no ovarian abnormality, which was confirmed by mini laparotomy and histological study of peritoneal thickened tissue. Treatment consisted of neoadjuvant chemotherapy, with a good response. This case shows the role of imaging in the preoperative diagnosis of appendicular mucoceles; CT scan and MRI, which are useful tools in identifying undetermined lesions of the appendix.     

Clinical Value of CT-Guided Needle Biopsy for Retroperitoneal Lesions

Objective

The purpose of this study was to investigate retrospectively the clinical procedural performance of CT-guided needle biopsy for retroperitoneal lesions.

Materials and Methods

CT-guided needle biopsy was performed in 74 consecutive patients (M:F = 44:30; mean age, 59.7 years) with retroperitoneal lesions between April 1998 and June 2009. The target lesion ranged from 1.5 to 12.5 cm in size. The biopsy access path ranged from 3.5 to 11.5 cm in depth. A biopsy specimen was obtained using an 18-gauge core needle under a CT or CT-fluoroscopy guidance and with the patient under local anesthesia. The histopathological diagnoses from the biopsies were obtained. The diagnostic confirmation of the subtype of lymphoma was evaluated.

Results

Satisfactory biopsy samples were obtained in 73 (99%) of 74 patients and a pathological diagnosis was made in 70 (95%) of 74 patients. Sixty three lesions were malignant (45 lymphomas, nine primary tumors, nine lymph node metastases) and seven were benign. The subtype of lymphoma was specified in 43 (96%) of 45 patients who were diagnosed with lymphoma. Analysis of the value of CT-guided biopsy in this series indicated 63 true positives, zero false positive, six true negatives and five false negatives. This test had a sensitivity of 93%, a specificity of 100% and an accuracy of 93%. No major complications were seen and minor complications were noted in seven patients (five with local hematomas, two with transient pain at the puncture site).

Conclusion

CT-guided needle biopsy for retroperitoneal lesions is highly practical and useful, and particularly for determining the subtypes in patients with lymphoma.     

腹膜假性粘液瘤的临床病理与影像表现分析

目的:探讨腹膜假性粘液瘤的临床影像学表现及病理组织学特征,提高对本病的鉴别诊断水平。方法:选取13例经手术及病理证实的腹膜假性粘液瘤,全部病例均行腹部CT检查,分析其两种临床病理分型(良性DPAM和恶性PMCA)的影像学表现。结果:两型腹膜假性粘液瘤有部分共同的CT表现,比如凝胶状腹水、肝脾边缘扇贝形压迹、肠系膜的浸润性改变、实质器官内浸润性病灶,以及腹膜粘液团在两型均可见到,不同的征象在于大量粘液蛋白性腹水和粘液团块中的钙化更多见于DPAM,网膜饼、淋巴结病变、网膜种植性团块以及原发病灶的显示更多见于PMCA。DPAM常常没有网膜饼形成,但常可见典型的肝脏边缘压迹。结论:两型腹膜假性粘液瘤的影像学表现各具有一定的特征性,充分认识其CT征象的不同有利于放射诊断医师作出正确诊断。     

Mucocele of the appendix. Retrospective study of 10 cases

PURPOSE: The purpose of our work was to assess the value of abdominal sonography (US) and computed tomography (CT) in the preoperative diagnosis of appendiceal mucocele. MATERIAL: and methods. We retrospectively reviewed 10 cases of mucocele of the appendix, 7 cases without pseudomyxoma peritonei, and 3 cases with pseudomyxoma peritonei. All cases were investigated radiologically by plain film and US, barium enema was performed in 3 cases and CT in 5 cases. RESULTS: Mucoceles of the appendix are rare and their clinical presentation is not specific. US confirms the appendicular involvement, but often poses the differential diagnosis with acute inflammation, abscess or localized appendicular peritonitis. CT appears as a mandatory examination since it allows accurate preoperative diagnosis period. In this series, the diagnosis was made preoperatively in the 5 cases where CT had been performed. CONCLUSION: US is useful to confirm the abnormal pattern of the appendix but does not allow accurate diagnosis of mucocele. CT is more specific and accurate for diagnosis of mucocele of the appendix.     

Localized pseudomyxoma peritonei in the female pelvis simulating ovarian carcinomatous peritonitis

Two cases of localized pseudomyxoma peritonei in the female pelvic cavity associated with a ruptured appendiceal mucocele and ovarian involvement that mimicked ovarian carcinomatous peritonitis were evaluated. Subtle omental irregularity adjacent to the cecum may suggest the hidden appendiceal origin reflecting localized carcinomatous peritonitis caused by the occult rupture of the mucocele. Mucinous fluid-like materials were localized in the pelvic cavity with scalloping of the uterus, which may be the diagnostic finding of pseudomyxoma peritonei.     

Abdominal plexiform neurofibromatosis simulating pseudomyxoma peritonei on computed tomography

We present and discuss an unusual case of extensive abdominal plexiform neurofibromatosis that simulated pseudomyxoma peritonei on CT. Multiple low density subdiaphragmatic masses caused scalloped liver margins and thickening of the mantle, which displaced bowel loops centrally, suggesting the diagnosis of pseudomyxoma peritonei. However, open biopsy revealed plexiform neurofibromatosis.     

Imaging findings of urachal mucinous cystadenocarcinoma associated with pseudomyxoma peritonei

Pseudomyxoma peritonei is an uncommon neoplastic condition in which gelatinous fluid-like materials are observed in the peritoneal cavity caused by the dissemination of mucinous adenocarcinoma. Although ruptured appendiceal mucocele is the most common cause, tumors arising from other organs may also cause pseudomyxoma peritonei. We report the imaging findings of an extremely rare case of urachal mucinous adenocarcinoma associated with pseudomyxoma peritonei on computed tomography and magnetic resonance imaging with histopathologic correlation.     

Peritoneal pseudomyxoma. Diagnostic role of CT and ultrasonics

Pseudomyxoma peritonei is an uncommon disorder, usually the sequelae of mucocele or mucinous adenocarcinoma of the appendix or mucinous cistoadenocarcinoma of the ovary. Two cases of pseudomyxoma peritonei were examined by ultrasound and one case by CT. US revealed, in a case, multiple echogenic small masses scattering on the peritoneal surface or floating in ascites. CT showed, in the second case, a huge mass consisting of a low attenuation material with internal septation. Also a perforation of intestinal loops in the mass was demonstrated. CT and US appearance of pseudomyxoma peritonei in our experience and in previously reported cases are discussed.     

腹膜假粘液瘤影像诊断价值(附25例分析)

目的:探讨腹膜假性粘液瘤的影像表现及对本病的诊断价值。方法:回顾性分析25例经手术及病理证实病例的影像表现。结果:腹膜假性粘液瘤有以下影像表现:①腹腔弥漫积液(25/25),肝、脾边缘病灶CT值明显高于腹盆腔病灶;②肝、脾边缘"扇贝样"压迹(25/25);③腹、盆腔散在点状、不规则索条状钙化灶(18/25);④可肝(2/25)、脾(10/25)转移,脾脏转移多见;⑤腹膜后不受累及(25/25);⑥磁共振T2WI显示病灶内有多发不规则分隔(2/2)。结论:PMP的影像学检查应以CT检查为首选,结合MR表现,应能大部分准确术前诊断,对累及范围也能准确评估,在PMP患者的复发和病情评估中也有重要价值。     

腹膜腔囊性病变的CT表现

目的：探讨腹膜腔囊性病变的CT诊断及应用价值。方法：对照分析57例腹膜腔囊性病变的CT表现和手术、病理结果。结果：21例腹膜腔囊肿或囊腺瘤、囊腺癌CT均表现为边界清晰的囊性或囊实性包块,7例肠系膜囊肿发现囊肿与肠系膜根部相连。5例腹膜腔假性黏液瘤则在肝脏前、后间隙和结肠下间隙见多个有分隔状囊性肿块。3例腹膜腔囊性间皮瘤局限于下腹腔,壁稍厚,有强化。4例腹膜腔淋巴管瘤位于胃脾肾间隙和胃肝间隙,5例腹膜腔血肿均有外伤史,表现为上腹部器管间隙内边缘清晰的囊性包块。12例腹膜腔脓肿均有腹部手术和术后发热史。结论：CT能清晰地显示腹膜腔囊性病变的部位、形态和范围,对临床诊断和治疗有重要价值。     

Angiography of nonneoplastic retroperitoneal masses

Although noninvasive imaging modalities can be used to initially detect retroperitoneal masses, angiography is still desirable for several reasons in those cases in which surgery is contemplated. The latter can forewarn the surgeon as to possible hemorrhagic complications in highly vascular lesions. In some cases it can predict the malignant potential of the lesion. Finally, since these masses may derive blood supply from multiple sources, a vascular “road map” is provided to the surgeon. The angiographic findings of malignant retroperitoneal tumors are well known, but very little has been published dealing with benign nonneoplastic retroperitoneal masses. We have performed angiography in 11 surgically proven nonneoplastic retroperitoneal masses (9 inflammatory lesions, 2 hematomas). Major arterial or renal displacement occurred in 10. The 2 hematomas and 3 inflammatory lesions were totally avascular; 6 of the 9 inflammatory lesions revealed fine neovascularity and 5 of these 6 had an associated capillary blush. Sources of vascular supply included the lumbar, renal capsular, superior mesenteric, and gastroduodenal arteries. Although angiography is helpful in preoperative evaluation of retroperitoneal masses for the aforementioned reasons, it may be difficult or impossible to differentiate benign from malignant lesions based on the angiographic findings alone. Supported in part by USPHS grants HL 20895, GM 18674, and HL 07334     

多层螺旋CT对腹膜假性黏液瘤的诊断价值

目的 探讨腹膜假性黏液瘤的MSCT表现.方法 搜集经手术、病理证实的腹膜假性黏液瘤11例,回顾性分析其CT表现.结果 腹膜假性黏液瘤的MSCT平扫见腹腔不规则囊实性肿块,CT值18.5～27.6 HU;肝脾等实质脏器边缘扇贝样或结节状压迹,脏器周围、网膜间隙、腹腔、盆腔见大量黏液性腹水;腹膜、大小网膜弥漫性不规则增厚;增强扫描显示囊实性病变仅见囊壁、网膜、腹膜轻度强化,囊内病灶无明显强化.结论 MSCT检查对该病的诊断及鉴别诊断具有重要的价值.     

Computed tomography and magnetic resonance of pseudomyxoma peritonei

Computed tomographic and magnetic resonance (MR) findings in a case of pseudomyxoma peritonei arising from a mucoid cystadenoma of the ovary are presented. The possible diagnostic aid of MR is discussed.