A variety of entities may mimic drainable abscesses. This can lead to misdiagnosis of these entities, unnecessary percutaneous placement of a pigtail drainage catheter, other complications, and delay in appropriate treatment of the patient. Types of entities that may mimic drainable abscesses include neoplasms (lymphoma, gallbladder cancer, gastrointestinal stromal tumor, ovarian cancer, mesenteric fibromatosis, ruptured mature cystic teratoma, recurrent malignancy in a surgical bed), ischemia/infarction (liquefactive infarction of the spleen, infarcted splenule), diverticula (calyceal, Meckel, and giant colonic diverticula), and congenital variants (obstructed duplicated collecting system). Postoperative changes, including expected anatomy after urinary diversion or Roux-en-Y gastric bypass and small bowel resection, may also pose a diagnostic challenge. Nonpyogenic infections (Mycobacterium tuberculosis, Mycobacterium avium complex, echinococcal cysts) and inflammatory conditions such as xanthogranulomatous pyelonephritis and gossypiboma could also be misinterpreted as drainable fluid collections. Appropriate recognition of these entities is essential for optimal patient care. This article exposes radiologists to a variety of entities for which percutaneous drainage may be requested, but is not indicated, and highlights important imaging findings associated with these entities to facilitate greater diagnostic accuracy and treatment in their practice. ^©RSNA, 2018.

To investigate the clinical presentation, diagnosis, and treatment of giant colonic diverticulum (GCD, by means of a complete and updated literature review). GCD is a rare manifestation of diverticular disease of the colon. Less than 200 studies on GCD were published in the literature, predominantly case reports or small patient series.

A systematic review of the literature was performed using the Embase and PubMed databases to identify all the GCD studies. The following MESH search headings were used: "giant colonic diverticulum"; "giant sigmoid diverticulum". The "related articles" function was used to broaden the search, and all of the abstracts, studies, and citations were reviewed by two authors. The following outcomes were of interest: the disease and patient characteristics, study design, indications for surgery, type of operation, and post-operative outcomes. Additionally, a subgroup analysis of cases treated in the last 5 years was performed to show the current trends in the treatment of GCD. A GCD case in an elderly patient treated in our department by a sigmoidectomy with primary anastomosis and a diverting ileostomy is presented as a typical example of the disease.

In total, 166 GCD cases in 138 studies were identified in the literature. The most common clinical presentation was abdominal pain, which occurred in 69% of the cases. Among the physical signs, an abdominal mass was detected in 48% of the cases, whereas 20% of the patients presented with fever and 14% with abdominal tenderness. Diagnosis is based predominantly on abdominal computed tomography. The most frequent treatment was colic resection with en-bloc resection of the diverticulum, performed in 57.2% of cases, whereas Hartmann's procedure was followed in 11.4% of the cases and a diverticulectomy in 10.2%. An analysis of sixteen cases reported in the last 5 years showed that the majority of patients were treated with sigmoidectomy and en-bloc resection of the diverticulum; the postoperative mortality was null, morbidity was very low (1 patient was hospitalized in the intensive care unit for postoperative hypotension), and the patients were discharged 4-14 d after surgery.

Giant colonic diverticulum is a rare manifestation of diverticular diseases. Surgical treatment, consisting predominantly of colonic resection with en bloc resection of the diverticulum, is the preferred option for GCD and guarantees excellent results.

Formation of a fistula to a digestive organ is an extremely rare phenomenon in cases of ovarian carcinoma. We report a case of ovarian clear-cell carcinoma complicated by formation of a sigmoid colon fistula, and review the related literature. A 61-year-old woman, who had undergone hysterectomy and right salpingo-oophorectomy due to myoma and an ovarian tumor, developed bloody bowel discharge and abdominal distention. Computed tomography revealed a huge pelvic tumor with a thickened wall and internal gas. As the patient also had severe anemia and peritonitis, emergency laparotomy was performed, and intraoperatively it was noted that the tumor was tightly attached to the sigmoid colon, and contained bloody pus. Left salpingo-oophorectomy was performed and pathological examination of the specimen revealed fistula formation between the ovarian tumor and the sigmoid colon. The tumor was diagnosed as left ovarian clear-cell carcinoma, but no diverticulum or direct tumor invasion was evident around the fistula. The patient was given chemotherapy with paclitaxel and carboplatin, and she is now doing well after 9 months with no evidence of tumor recurrence. Although fistulation to the digestive tract is very rare in cases of ovarian cancer, it must be diagnosed and treated promptly because severe inflammation can make it potentially life-threatening.

Giant colonic diverticulum is a rare complication of diverticular disease of the colon and is thought to result, in most cases, from a "ball-valve" effect. The presentation and clinical course can be variable and confusing. The most common symptoms are abdominal pain and a palpable abdominal lump, with many patients presenting acutely with complications such as perforation and peritonitis. Preoperative diagnosis requires a high degree of suspicion and needs to be differentiated from sigmoid volvulus, caecal volvulus, intestinal duplication cyst, pneumatosis cystoidis intestinalis, and similar conditions. A plain x-ray and computed tomography (CT) scan of the abdomen shows a huge air-filled cyst termed "balloon sign" and confirms the diagnosis. The barium enema shows a communication with the bowel in most cases. In view of the high incidence of complications, treatment is advised even in asymptomatic cases and consists of excision of the cyst with resection of the adjacent colon with primary anastomosis. This treatment would, in most cases, be a sigmoid colectomy. Percutaneous drainage and Hartmann's procedure may be appropriate in some cases who present with a well-formed abscess or gross fecal peritonitis, respectively. A case is described, and the literature is reviewed.

Giant diverticula of the small intestine and colon are rare. Four cases treated at our institution in the last year are reported and compared to published cases; specific features and those which differentiate them from abdominal pseudocysts are described. They most commonly present a clinical tableau similar to commonplace diverticular disease. Awareness of this unusual condition and a good CT study are the keys to diagnosis. Giant diverticula may be acquired or congenital. The acquired type is simply a more spectacular version of commonplace diverticulosis while the congenital type, having a muscular wall and myenteric plexus, is more akin to intestinal duplications. Treatment is surgical and, in the case of sigmoid giant diverticula, usually requires a colon resection similar to that required for sigmoid diverticulitis.

Giant diverticulum of the colon is a rare complication of the colonic diverticulosis. It generally involves the sigmoid colon. In the chronic form, without symptoms or with only a few non-specific symptoms, an abdominal mass is frequently palpable. A plain abdominal radiogram, showing a gas-filled cyst, can suggest the diagnosis. If needed, an abdominal CT scan is appropriate and seems to be more accurate than a barium enema. The treatment of choice is a segmental resection of the colon involving the giant diverticulum, followed by a direct anastomosis. Despite the old age of these patients, both postoperative morbidity and mortality are low and justify such a radical approach. The acute clinical presentation (about 20%) is generally due to a peritonitis by perforation of the giant diverticulum and requires an emergency colectomy.

We describe herein an extremely rare case of clear cell type ovarian carcinoma resulting in fistula formation into the colon and intestine. The patient was a 61-year-old woman in whom a large tumor with extravasation from the sigmoid colon was found by barium enema examination. The tumor was preoperatively diagnosed as left ovarian cancer by angiography which showed the tumor feeder arising from the left ovarian and uterine arteries.

The imaging appearances of three patients with a giant sigmoid diverticulum are described. The prominent feature was a large gaseous lucency noted in the lower abdomen on plain radiographs. Computed tomography (CT) was undertaken in two cases and in these a large gas filled collection was identified containing a small quantity of fluid. In the third case the collection was aspirated, contrast medium injected and a communication with the large bowel demonstrated. The condition is uncommon and needs to be distinguished from sigmoid and caecal volvulus.

Giant colonic diverticulum are rare, with 103 reported cases in 95 patients. The experience of any one surgeon is limited. We aimed to retrospectively review our experience and to review the literature on origin, pathology, and management of this rare and unusual problem.

Cases were identified by review of pathologic database and by computerized audit from three hospitals.

Five giant colonic diverticulum were identified in four patients, and the pathology and management were reviewed.

A definition and classification system of giant colonic diverticulum is suggested. Giant colonic diverticulum should be the universal term to cover all colonic diverticulum larger than 4 cm, and we suggest that there are two types based on histology. Literature review reveals 103 reported cases in 95 patients. Type I (87 percent) is a pseudodiverticulum, perhaps related to conventional diverticular disease, whereas Type II (13 percent) is a true diverticulum, which is probably a type of communicating cystic congenital duplication. These lesions tend to occur in the sigmoid colon (93 percent) and present with complications similar to conventional diverticular disease. In the presence of conventional diverticular disease, consideration should be given to anterior resection, and in the absence, diverticulectomy should be considered.

While diverticulosis of the colon is a relatively common disease, a solitary giant diverticulum (GD) of the sigmoid is rare. Although there exist some theories about the formation of a GD, none is really conclusive. Symptoms are similar to diverticular disease, and diagnosis is easy with the aid of radiology. Early surgical treatment is necessary since the complication rate is high (19%).

A case of sigmoid colon fistula complicating ovarian cystadenocarcinoma is reported. The entity demonstrated a large air-filled, thin-walled cystic lesion during barium enema examination. The differential diagnosis of distended air-filled cystic lesions is discussed and expanded to include colonic fistula complicating ovarian neoplasms.

Although most often clinically silent, colonic diverticula are responsible for a large number of gastrointestinal illnesses in our society. Complications of diverticular disease, including perforation and hemorrhage, may occur in 15% to 20% of patients with diverticula during their lifetime, and although often mild and self-limiting diseases, they too frequently cause life-threatening problems that require prompt surgical intervention. Despite a cadre of sophisticated laboratory and radiologic tests that have been developed to aid in the diagnosis of complicated diverticular disease, the diagnosis and treatment of diverticulitis still relies heavily on patient history, physical examination, physician judgment, and the patient's clinical response to treatment. Thus it is important for the managing physician to fully understand the pathogenesis of diverticula, the clinical consequences and modes of presentation of complicated diverticular disease, and the array of interventions available for treatment of these problems. This monograph summarizes our knowledge of diverticular disease to date and tries to give specific guidelines for the treatment of patients with complicated diverticulitis. However, it must be understood that the presentation and severity of these complications vary widely from patient to patient. Thus one cannot take a single approach toward a patient who has diverticulitis or diverticular bleeding. Rather, successful outcomes depend on an individual approach to each patient while maintaining certain generally accepted principles of treatment.