Multinucleated Giant Cell Reaction Research Articles

A Lymphoepithelioma-Like Intrahepatic Cholangiocarcinoma With Massive Multinucleated Giant Cell Reaction.

Lymphoepithelioma-like intrahepatic cholangiocarcinoma (LEL-ICC) is a rare liver tumor that appears as a hepatic nodule on imaging with a specific pathological pattern, and the definitive diagnosis relies on its pathological histomorphology, immunophenotype, and Epstein-Barr encoding region test. Radical surgical resection is the primary treatment modality, and immunotherapy is expected to be a new adjuvant treatment option. LEL-ICC with massive multinucleated giant cell infiltration has not been reported so far. In this article, we report a patient with LEL-ICC showing massive multinucleated giant cell infiltration, review the relevant literature, and analyze its clinicopathological features and prognosis to accumulate experience for the accurate diagnosis of LEL-ICC.

Giant Cell Tumor: Pathogenesis and Clinical Manifestation

A giant cell tumor of bone (GCTB) as known as a benign bone tumor (neoplasm) is aggressive locally and frequently recurs, and it is characterized by the growth of mononuclear stromal cells and datia cells that resemble osteoclasts. GCTB has varying incidence rates and has been shown to have high mortality. GCTB patients have several treatment options, but the majority of patients still experience recurrence and even metastasis to other organs. This literature review aims to explain more deeply about Giant Cell Tumor (GCT) starting from the definition, etiology, epidemiology, pathogenesis, clinical manifestations and treatment options so that patients get a better prognosis. This literature review was conducted using the keywords "Giant Cell Tumor AND pathogenesis AND clinical manifestation" from PubMed dan Google Scholar. The results of the literature review carried out are that the molecular and biological pathogenesis of GCTB consists of 4 processes, namely tumorigenesis of neoplastic mononuclear stromal cells, generation of reactive multinucleated giant cells, bone resorption/migration, and bone matrix remodeling for angiogenesis, invasiveness, and metastasis. Besides, the histological picture of GCTB contains "reactive" osteoclasts such as multinucleated giant cells (Giant Cells/GC), round cells such as macrophages and spindle stromal cells such as "neoplastic" fibroblasts (mononuclear stromal cells/SC) which are important findings in establishing the diagnosis. In conclusion, staging and management are very important to produce a better prognosis and reduce recurrence rates in GCTB patients.

WEO Newsletter.

WEO Newsletter.

Absence of multinucleated giant cell reaction as an indicator of tumor progression in oral tongue squamous cell carcinoma.

The aim of this study was to evaluate the presence and distribution of multinucleated giant cell (MGC) reactions in 61 cases of OTSCC and to verify the association of this microscopic finding with clinicopathological parameters (gender, age, tumor size/extent, regional lymph node metastasis, distant metastasis, clinical stage, and histopathological grade of malignancy). Clinical data were collected from medical records and the histopathological grade of malignancy of OTSCCs was evaluated using the World Health Organization (WHO) grading system. The presence and distribution of MGC reaction in high power fields (HPFs) were evaluated in hematoxylin-eosin-stained histological sections. In all cases containing MGCs, immunohistochemical analysis for CD68 was performed in order to confirm the histiocytic nature of these cells. Twenty-one (34.4%) cases had MGC reactions, with a higher frequency of the focal distribution pattern (57.1%). All MGCs were immunohistochemically positive for CD68. The absence of MGC reaction was significantly associated with regional lymph node metastasis (PR: 2.75; 95% CI 1.05-7.20; p = 0.027), advanced clinical stage (PR: 3.37; 95% CI 1.28-8.85; p = 0.006), and moderately/poorly differentiated tumors (PR: 3.36; 95% CI 1.51-7.48; p = 0.001). No significant associations were observed between the distribution of MGCs and clinicopathological parameters (p > 0.05). Taken together, the results of this study suggest that the absence of MGC reaction may represent an indicator of tumor progression in OTSCCs.

Clinical application of negative-pressure wound therapy in uncomplicated cardiac pacemaker pocket infection

Objective: To investigate the feasibility of negative-pressure wound therapy (NPWT) in the treatment of uncomplicated cardiac pacemaker pocket infection. Methods: From January 2013 to March 2020, 35 patients with uncomplicated cardiac pacemaker pocket infection were admitted to the Department of Cardiology of Peking University First Hospital, including 21 males and 14 females, aged 27 to 84 years. The retrospective cohort study was conducted. After a complete debridement followed by continuous NPWT (with negative pressure of -16.67 kPa), the pulse-generator was inserted into the new pocket between the musculus pectoralis major and pectoralis minor. Pressure drainage tube was put into the old pocket space. NPWT with the same mode was used again for 5 to 7 days after the wound was closed. The removed pocket tissue of patients was observed with hematoxylin-eosin staining. The wound healing on 10 to 12 days after the operation of pacemaker replacement was observed, and the recurrence of infection was observed during 6 to 42 months follow-up after operation. Results: The fibrous sac wall was observed in pocket tissue of the patients, and the tissue was partially covered with stratified epithelium, with many chronic inflammatory cells infiltration. Multinucleated giant cell reaction was observed in the tissue of some patients. Ten to twelve days after the operation of pacemaker replacement, 35 patients had good wound healing, and sutures were removed. After 6 to 42 months follow-up after operation, 31 patients were cured with no recurrence of infection and the wounds were well-healed; 4 patients who had recurrent infection received whole system of pacemaker removal after the operation. Conclusions: On the premise of complete debridement, NPWT is an alternative treatment for patients with uncomplicated cardiac pacemaker pocket infection.

Dermoid and epidermoid cysts of the oral cavity: a 48-year retrospective study with focus on clinical and morphological features and review of main topics.

Background Dermoid and epidermoid cysts are slow-growing, benign developmental cysts that arise from ectodermal tissue and can occur anywhere in the body. Less than 7% of these cysts involve the head and neck region, with only 1.6% of cases presenting in the oral cavity. To evaluate the clinical and histopathological features of dermoid (DCs) and epidermoid (ECs) cysts stored in the archives of a referred Oral Pathology Service over a 48-year-period, and to review current concepts about these cysts. Material and Methods All DCs and ECs were reviewed, and clinical data were obtained from the patient records. Fourteen cases of DCs and thirteen cases of ECs were re-evaluated microscopically by 2 oral pathologists. Results Among 15.387 cases, 14 (0.09%) had a histopathological diagnosis of DCs and 13 (0.08%) of ECs. For DCs, ten (71.4%) patients were women, with the mean age of 37.2 years. All DCs were lined by a stratified squamous epithelium (100%), with gut and respiratory epithelium observed in 1 (7.1%) and 2 (14.3%) cases, respectively. Chronic inflammatory cells, melanin, multinucleated giant cell reaction, and Pacini bodies were also observed. For ECs, eight (61.5%) cases were in women, and the mean age was 38.2 years. All ECs were lined by a stratified squamous epithelium (100%). Chronic inflammatory cells, melanin pigmentation, and adipose tissue were observed in the fibrous capsule. Conclusions Our results suggest that stratified squamous epithelium is the predominant epithelial lining of these cystic lesions. Also, we may find some unusual findings in DCs, such as Pacini bodies. Key words:Non-odontogenic cysts, epidermoid cysts, dermoid cysts, diagnosis.

Multinucleated Giant Cell Reaction in Well-differentiated Squamous Cell Carcinoma of Oral Cavity

Multinucleated Giant Cell Reaction in Well-differentiated Squamous Cell Carcinoma of Oral Cavity

Application value of vacuum sealing drainage in the wound repair after resection of pilonidal sinus

Objective To explore the application value of vacuum sealing drainage (VSD) in wound repair after resection of pilonidal sinus. Methods The retrospective cross-sectional study were conducted. The clinical data of 11 patients with pilonidal sinus who were admitted to the China-Japan Union Hospital of Jilin University from April 2015 to June 2016 were collected. All the patients received resection of pilonidal sinus after preoperative antibiotic therapy, and then received postoperative VSD and regular treatments of anti-infection and dressing changes. Observation indicators: (1) treatment situations: surgical procedures, operation time, volume of intraoperative blood loss, gross specimens, results of postoperative pathological examination, postoperative treatment (VSD), growth condition of granulation tissue, duration of hospital stay and treatment expenses; (2) follow-up situations: cases with follow-up, follow-up time, wound healing, postoperative complications and disease recurrence. Follow-up using outpatient examination and telephone interview was performed to detect the wound healing, postoperative complications and disease recurrence up to July 2017. Measurement data with normal distribution were represented as ±s. Measurement data with skewed distribution were described as M(range). Results (1) Treatment situations: all the 11 patients underwent successful surgery for pilonidal sinus. The operation time and volume of intraoperative blood loss were respectively (79±19)minutes and (10±4)mL. Observation of gross specimens of 11 patients: hairs were scattered within the resected lesions in 7 patients, and hairs didn't found in 4 patients. Results of postoperative pathological examination of 11 patients: there were acute and chronic inflammation accompanied with granulation tissues in the subepithelial fibrous tissues, and discrete multinucleated giant cell reaction. Of 11 patients undergoing VSD, 9 received VSD material changes for 3 times, 2 received VSD material changes for once, and wounds were not sutured after VSD removal. The new granulation tissues of 11 patients were found at (5.9±1.3)days postoperatively. The duration of hospital stay and treatment expenses were respectively (33.3±8.3)days and (37 790±8 811)yuan. (2) Follow-up situations: 11 patients were followed up for 12-18 months, with a median time of 14 months. The wound healing time was (41.0±9.0)days. Of 11 patients with follow-up, 10 were in the primary healing, 1 who was complicated with wound infection and abscess of wound deep surface underwent sacral wound incision and drainage, gauze packing and routine dressing change, and then wound healed completely. There was no recurrence in 11 patients during the follow-up. Conclusions The VSD has great application value in managing wounds after resection of pilonidal sinus, with a lower incidence of wound infection and smaller scar, and it is worth recommending to patients with wide wounds, high tension and serious infection. Key words: Pilonidal sinus; Infections diseases; Sacrococcygeal region; Surgical procedures, operative; Vacuum sealing drainage

Orthokeratinized odontogenic cyst associated with multinucleated giant cell reaction: report of unusual findings

ABSTRACT Orthokeratinized odontogenic cysts are developmental odontogenic cysts, presenting with low frequency, low rate of recurrence and their ethiopathogenesis is unknown. Radiographically, they show a radiolucent area in the mandibular posterior region. The aim of this report is to describe an unusual case of orthokeratinized odontogenic cysts, radiographically exhibiting radiopaque areas with an aspect of calcifications in the lesion. Based on this, the clinical hypothesis of ameloblastic fibro-odontoma was suggested. After incisional biopsy and microscopic analysis, the conclusive diagnosis was orthokeratinized odontogenic cysts. The radiopaque foci were observed to be associated with a foreign body reaction. The patient was submitted to surgery under local anesthesia, with intraoral access for complete excision of the lesion and to re-establish esthetics. After follow-up of 24 months there were no signs of recurrence. Knowledge of this type of reaction is important because of the risk that the lesion may mimic a potentially more aggressive lesion, affecting the choice of treatment.

Evaluation in vivo of biocompatibility of differents resin-modified cements for bonding orthodontic bands.

The focus of this study was to test the hypothesis that there would be no difference between the biocompatibility of resin-modified glass ionomer cements. Sixty male Wistar rats were selected and divided into four groups: Control Group; Crosslink Group; RMO Group and Transbond Group. The materials were inserted into rat subcutaneous tissue. After time intervals of 7, 15 and 30 days morphological analyses were performed. The histological parameters assessed were: inflammatory infiltrate intensity; reaction of multinucleated giant cells; edema; necrosis; granulation reaction; young fibroblasts and collagenization. The results obtained were statistically analyzed by the Kruskal-Wallis and Dunn test (P<0.05). After 7 days, Groups RMO and Transbond showed intense inflammatory infiltrate (P=0.004), only Group RMO presented greater expression of multinucleated giant cell reaction (P=0.003) compared with the control group. After the time intervals of 15 and 30 days, there was evidence of light/moderate inflammatory infiltrate, lower level of multinucleated giant cell reaction and thicker areas of young fibroblasts in all the groups. The hypothesis was rejected. The Crosslink cement provided good tissue response, since it demonstrated a lower level of inflammatory infiltrate and higher degree of collagenization, while RMO demonstrated the lowest level of biocompatibility.

Multinucleated giant cell reaction in lower lip squamous cell carcinoma: a clinical, morphological, and immunohistochemical study.

Multinucleated giant cell (MGC) reactions have been identified in several malignancies, but their frequency and significance in lower lip squamous cell carcinoma (SCC) are not established. This study evaluated the MGC reactions and their association with clinicopathological parameters in lower lip SCCs. The polarization profile of these cells (M1 or M2 macrophages) was also assessed. The presence and distribution of MGC reactions in high-power fields (400×) were evaluated in hematoxylin/eosin-stained histological sections of 91 lower lip SCCs. The histopathological grade of malignancy was evaluated using two grading systems (World Health Organization [WHO] and Malignancy Grading of the Deep Invasive Margins). The histiocytic nature (CD68) and polarization profile (M1-HLA-DR+ or M2-CD163+) of MGCs were evaluated by immunohistochemistry. Multinucleated giant cell reaction was identified in 36 (39.6%) cases, and its frequency was 3.3 times higher in well/moderately differentiated tumors than in poorly differentiated tumors (WHO grading system) (P = 0.006). For Malignancy Grading of the Deep Invasive Margins, the frequency was 2.03 times higher in highly/moderately keratinized tumors than in tumors with minimal/no keratinization (P = 0.012). No significant associations were observed between the presence/distribution of MGCs and clinical parameters (tumor size, lymph node metastasis, distant metastasis, and clinical stage) (P > 0.05). All MGCs were positive for CD68 and there was a predominance of HLA-DR+ over CD163+ MGCs (P = 0.031). Multinucleated giant cell reactions may not be involved in tumor progression in lower lip SCCs. In this microenvironment, MGCs tend to exhibit a predominantly M1 phenotype and may represent a foreign body reaction to SCC keratin pearls.

Diagnostic pitfalls of infarcted Warthin tumor in frozen section evaluation.

Warthin tumor (WT) is the second most common benign salivary gland neoplasm and has characteristic cytologic and histologic findings. Fine-needle aspiration is a common and useful preoperative diagnostic technique, which sometimes leads to ischemic injury resulting in the infarction of these lesions. Infarcted WT may demonstrate variable gross and histologic alterations that may render the diagnosis challenging, particularly during intraoperative frozen section evaluation. In this study, we collected 11 resection specimens from 9 patients with infarcted WT. Seven patients were men and 2 were women, ranging from 49 to 85 years (mean, 69). All the patients had fine-needle aspiration before the resection. Macroscopically, the tumors were tan-white and contained soft, yellow, exudative material. The histologic findings were variable and included necrosis, ghosts of papillae, squamous metaplasia, cholesterol clefts, foamy macrophages, multinucleated giant cell reaction, necrotizing granulomas, and fibrosis. Each case predominantly demonstrated 1 or 2 of these histomorphologic features. In the permanent sections, additional sampling revealed foci of residual viable WT in 8 cases. Three cases were completely infarcted; however, they all had ghost-like papillae in which the architecture of WT was evident. Infarcted WT may present a diagnostic challenge during intraoperative frozen section evaluation. Associated morphologic alterations may preclude a definitive diagnosis of WT and may mimic malignancy. Awareness of the gross and microscopic features associated with infarcted WT is important, particularly for accurate frozen section evaluation of these salivary gland tumors.

Nontender Mass Over the Right Parotid Area

Aman inhis60spresentedwith a 1-year historyof apalpablepainless mass over the right parotid area. No facial pain, local tenderness, or facial palsy was noted. Physical examination revealed a 2.5 × 2.5-cm, freelymovable, elastic, nontendermassover the right parotid area. A head and neck fat-suppressed, postcontrast T1weighted imagedemonstrateda 1.7-cmmultilocularperipherallyenhancingmass in theanterior superficial lobeof therightparotidgland (Figure,A,arrowhead).Onclinicalandradiologicalgrounds, themost likely diagnosis was thought to be pleomorphic adenoma or Warthin tumor.Right superficial parotidectomywasperformed, and the entire lesion was surgically removedwithout complications. There was no recurrence at the 5-month follow-up. The specimen sent for pathological examination measured 3.6 × 3.0 × 1.5 cmandweighed6.9g.Grossly, therewasagray,wellcircumscribed tumor measuring 1.7 × 1.5 × 1.2 cm within the salivarygland.Onthecutsurface, thereweremultiplecysticspaces filled with light yellow and greasy materials in the tumor. Microscopically, the tumorwascomposedofvarious-sizedcysticepithelialnests of squamoid cells and sebaceous cells, admixedwith some salivary ducts in abackgroundofprominent lymphoid stroma (Figure,Band C).No cell atypia or desmoplastic stromawasnoted.Histiocytic aggregation and multinucleated giant cell reaction were also seen (Figure, D). What is your diagnosis? A B

The Clinical Approach Toward Giant Cell Tumor of Bone

We provide an overview of imaging, histopathology, genetics, and multidisciplinary treatment of giant cell tumor of bone (GCTB), an intermediate, locally aggressive but rarely metastasizing tumor. Overexpression of receptor activator of nuclear factor κB ligand (RANKL) by mononuclear neoplastic stromal cells promotes recruitment of numerous reactive multinucleated giant cells. Conventional radiographs show a typical eccentric lytic lesion, mostly located in the meta-epiphyseal area of long bones. GCTB may also arise in the axial skeleton and very occasionally in the small bones of hands and feet. Magnetic resonance imaging is necessary to evaluate the extent of GCTB within bone and surrounding soft tissues to plan a surgical approach. Curettage with local adjuvants is the preferred treatment. Recurrence rates after curettage with phenol and polymethylmethacrylate (PMMA; 8%-27%) or cryosurgery and PMMA (0%-20%) are comparable. Resection is indicated when joint salvage is not feasible (e.g., intra-articular fracture with soft tissue component). Denosumab (RANKL inhibitor) blocks and bisphosphonates inhibit GCTB-derived osteoclast resorption. With bisphosphonates, stabilization of local and metastatic disease has been reported, although level of evidence was low. Denosumab has been studied to a larger extent and seems to be effective in facilitating intralesional surgery after therapy. Denosumab was recently registered for unresectable disease. Moderate-dose radiotherapy (40-55 Gy) is restricted to rare cases in which surgery would lead to unacceptable morbidity and RANKL inhibitors are contraindicated or unavailable.

The Spectrum of Grossly Visible Pigmented Lesions in the Uterine Cervix

Pigmented lesions of the uterine cervix (UC) have not been systematically studied in the literature. Over an 18-mo period, we prospectively investigated the histologic spectrum of all macroscopically visible pigmented lesions of the UC. The incidence of pigmented UC was 1.6% (33/2118). Histologic examination revealed 32 cases (97%) with a histologic correlate, of which 26 lesions were of melanocytic nature including 25 blue nevi (BNs) (81%) and 1 melanotic macule (3%). The nonmelanocytic lesions included 1 case of focal granulomatous vasculitis (3%), 2 biopsy site-associated reactive changes with hemosiderin-laden macrophages (6.4%), 1 case of hemorrhagic Nabothian cyst (3%), 1 hemangioma (3%), and 1 case of multinucleated giant cell reaction to dark black carbon-like material (3%). Women with UC BN (1.2% incidence) were mostly whites (13/25, 52%) with a mean age of 47.4 yr (range, 31-64 yr). The number and size of BN per UC, all located in the endocervix, varied between 1 to 3 and 0.1 to 2 cm (mean, 0.68 cm). UC BN exhibited 3 distinct morphologic patterns: (1) stromal melanocytic focus composed of fine spindle cells (9/25, 36%); (2) mixed pattern with fine spindle, plump spindle, and epithelioid cells (15/25, 60%); and (3) nevoid stage with epithelioid cells (1/25, 4%). In contrast, cervical melanotic macule was located in the squamous epithelium of the ectocervix and characterized by hyperpigmentation of the basal keratinocytes admixed with scattered slightly enlarged melanocytes. In conclusion, pigmented lesions of the UC are not as uncommon as reported and mostly benign in nature. Several cases may require deeper levels for their detection and to exclude the rare phenomenon of UC melanoma.

Light Chain Renal Amyloidosis With Prominent Giant Cells

Clinical diagnosis of amyloidosis may be very challenging because signs, symptoms, and laboratory study results can be highly variable and may overlap with other disease entities. Amyloid has characteristic features on kidney biopsy, involving glomeruli, vessels, and/or interstitium as typically amorphous waxy material that is periodic acid-Schiff pale and Congo Red birefringent under polarized light. Electron microscopy demonstrates characteristic randomly oriented fibrils. However, in rare cases, amyloid may present with atypical morphologic features on kidney biopsy, closely mimicking other histopathologic diagnoses. We present a case of light chain (AL) κ amyloidosis with an unusual inflammatory infiltrate including prominent multinucleated giant cells in the interstitium and at the glomerular hilus. Amyloid was apparent within giant cells on Congo Red staining, as well as on ultrastructural evaluation. Together with prior studies of tumoral nonrenal amyloid and renal amyloid A, we suggest that the amyloid fibril constituents κ and serum amyloid A have some predilection for inciting the rare multinucleated giant cell reaction.

Lip Augmentation Dermal Filler Reactions, Histopathologic Features

Instances of perioral and labial foreign body reactions to a variety of injectable dermal fillers were selected from the oral and maxillofacial pathology and dermatopathology archives at Pacific Pathology Laboratory of San Diego with the objective being to engender a compilation of histopathologic characteristics that allow the pathologist to identify the inciting materials. All cases of foreign body reactions located in the lips and perioral regions were reviewed by four pathologists, retaining those cases with a history of injection lip augmentation as well as those with histologic features previously documented to represent dermal filler substances. In selected cases, Alcian blue pH 2.5 with and without hyaluronidase pretreatment was performed. Immunohistochemical markers for macrophages (CD 68), adipocytes (S-100) and keratinocytes (AE1/AE2) were undertaken. All instances presented as single or multiple submucosal plaques, nodules or swellings. Natural polymers including collagen, hyaluronate, hydroxyapatite, poly-L-lactate and synthetic polymers including carboxymethyl cellulose, dimethylpolysiloxane, and polyethyl methacrylate induce histologically unique features that allow for their identification. Host histopathologic responses included nodule without foreign body reaction, nodule with chronic inflammation, granuloma with epithelioid histiocytic and multinucleated giant cell reaction. Dermal filler foreign body host reactions in conjunction with the morphology of the foreign materials themselves are unique and can be differentiated from one another microscopically.

FNA diagnosis of osteoclast-like giant cell tumor of the pancreas

Osteoclast-like giant cell tumor of the pancreas is a rare non-endocrine neoplasm composed of reactive multinucleated giant cells admixed with mononuclear stromal cells. We report a case of osteoclast-like giant cell tumor of the pancreas in a 58-year-old female with vague clinical symptoms. Endoscopic ultrasound-guided aspirate from the mass revealed numerous characteristic osteoclast-like giant cells.

Clinicopathological observation of gastric cancer with pathological complete response following neoadjuvant chemotherapy

To observe the clinicopathological characteristics of gastric cancer with pathological complete response(pCR) following neoadjuvant chemotherapy. Data of gastric cancer patients who received neoadjuvant chemotherapy from 2002 to 2008 in the Beijing Cancer Hospital were reviewed. Five cases were found to have pCR. The slides were reviewed by two experienced pathologists independently. Histological structure, morphology of tumor cells, morphology and quantity of stromal cells were evaluated. Structure of the gastric wall was distinguishable in all the 5 cases, while distortion and rupture of muscular layer were found in 2 cases. Exudative inflammatory reaction was present in the whole gastric wall including the serosa layer. Three patients had ulcerative lesions with epithelial layer shedding, and atypical hyperplasia was found around the border of the ulcer, and vascular endothelial cells were swollen. Residual distorted necrotic tumor cells resided in 1 case only and no residual tumor cells was present in the other 4 patients. Significant hyperplasia of fibroblasts was present in 4 cases, large amount of lymphocytes infiltration in 3 cases including concurrent plasma cell infiltration in 1 case, multinucleated giant cell reaction in the muscular layer of 1 case, and foam cells aggregation in 1 case with mucinous adenocarcinoma. In addition, there were 2 cases with pCR had lymph node metastasis. For cases with pCR following neoadjuvant chemotherapy, heterogeneity of stromal cells reaction is found in previous tumor site. Furthermore, the response of primary tumor does not necessarily parallel to that of lymph nodes.

Crohn's disease and enterovesical fistulae: common things are common

A 39-year-old Caucasian male presented with a 5-day history of acute severe left iliac fossa pain (radiating to the umbilicus), vomiting and episodic pneumaturia associated with brown urinary sediment. There had been no reported alteration in bowel habit, anorexia or weight loss. On examination he was apyrexial and haemodynamically stable with only mild tenderness limited to the area of the left lower rectus sheath, inferior to the umbilicus. Four years earlier he had been diagnosed with Crohn's disease at a nearby hospital, following a similar episode of left iliac fossa pain; the diagnosis of Crohn's disease was based on computed tomography findings of a thickened ascending colon despite normal histology at colonoscopy. Since the diagnosis of Crohn's disease he had remained on regular mesalazine, with five episodes of similar pain (and occasional pneumaturia) treated with intravenous steroids for presumed exacerbations of Crohn's disease. Given the history of pneumaturia he was pending an outpatient magnetic resonance imaging scan to establish the presence of an enterovesical fistula. At admission, initial investigations revealed a negative urine dipstick for leucocytes and nitrites and only mildly raised inflammatory markers. A computed tomography scan demonstrated an abnormal sigmoid colon adherent to the bladder and anterior abdominal wall (Figure 1). There was also evidence of fluid within the left rectus abdominal sheath and of a fistulous tract between the bladder and sigmoid colon (Figure 2). Flexible sigmoidoscopy revealed an area of narrowing with tight angulation in the sigmoid colon and an abnormal red spot of uncertain aetiology, but there was no evidence of Crohn's disease macroscopically or histologically. Flexible cystoscopy showed thickening of the anterior dome of the bladder with a likely fistula opening superiorly, with non-specific cystitis on histology. Multidisciplinary team discussions concluded that the findings were more suggestive of a localized perforation of a sigmoid diverticulum 4 years earlier leading to secondary inflammatory erosion with the creation of a persistent enterovesical fistula. He therefore underwent a sigmoid colectomy and bladder wall repair. At operation a mass was found in the left iliac fossa adherent to the bladder and abdominal wall and 5 ml of pus drained from an abscess in the anterior abdominal wall. Histology showed an inflamed and ulcerated diverticulum in the sigmoid and an acute and chronic inflammation with foreign body type multinucleated giant cell reaction in the bladder. The patient made a good recovery postoperatively with an early discharge and his longstanding medication for Crohn's disease was stopped.